REFEMNCE COPY Do Not Remove from the Library

U S Fish and Wildlife Service National Wetlands Research Center

Biological Report 82 (11 112) un ime ooutevara TR EL-82-4

~ugust 1989 Lafayette Louisiana 70506

Species Profiles Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Mid-Atlantic)

SUMMER AND WINTER FLOUNDER

Fish and Wildlife Service Coastal Ecology Group

Waterways Experiment Station

US Department of the Interior US Army Corps of Engineers

B i o l o g i c a l R e p o r t 8 2 ( 1 1 1 1 2 ) TR EL-82-4 August 1989

S ~ e c i e s P r o f i l e s L i f e H i s t o r i e s and E n v i r o n m e n t a l R e q u i r e m e n t s o f C o a s t a l F i s h e s and I n v e r t e b r a t e s ( h i d - A t l a n t i c j

SllF~lvlER AND WINTER FLOUNDER

B a r b a r a H Gr imes M e l v i n T H u i s h and J Howard k e r b y J3 F i s h 2nd W i l d l i f e S e r v i c e

N o r t h C a r o l i n a C o o p e r a t i v e F i s h e r y 9 e s e a r c h U n i t D e ~ a r t m e n t o f Zoo1 o g y

r i o r t h C a r o l i n a S t a t e U n i v e r s i t y R a l e i g h NC 27695

and

D a v i d K o r a n US F i s h and W i l a l i f e S e r v i c e

N a t i o n a l Wet l ands R e s e a r c h C e n t e r 1 0 1 0 Gause B o u l e v a r d

S l i d e l l LA 70458

P r o j e c t Manager Edward P e n d l e t o n

US F i s h and W i l d l i f e S e r v i c e N a t i o n a l Wet l ands R e s e a r c h C e n t e r

1 0 1 0 Gause B o u l e v a r d S l i d e l l LA 70458

P e r f o r m e d f o r

C o a s t a l E c o l o g y Group Waterways E x p e r i m e n t S t a t i o n US Army C o r p s o f E n g i n e e r s

V i c k s b u r g MS 39180

and

USDepar tment o f t h e I n t e r i o r F i s h and W i l d l i f e S e r v i c e R e s e a r c h and Deve lopment

N a t i o n a l W e t l ands R e s e a r c h C e n t e r W a s h i n g t o n DC 20240

T h i s s e r i e s s h o u l d be r e f e r e n c e d as f o l l o w s

US F i s h an3 W i l d l i f e S e r v i c e 1983-1988 Spec ies p r o f i l e s l i f e h i s t o r i e s and env i ronrner i ta l r e q u i r e m e n t s o f c o a s t a l f i s h e s dnd i n v e r t e b r a t e s J S F i s h Wild1 Serv B io l Rep 82 (11) US Army Corps o f Engineers TR EL-82-4

T h i s p r o f i l e s h o u l d b e c i t e d as f o l i o w s

Grimes BH MT Hu ish JH Kerby and D Poran 1989 Spec ies p r o f i l e s l i f e h i s t o r i e s and e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s (M id -A t1 ant ic ) - -summer and w i n t e r f l o u n d e r US F i s h 4 i l d l Serv B i o l Rep 82(11112) US Army Corps o f Eng ineers TR EL-82-4 18 pp

PREFACE

T h i s spec ies p r o f i l e i s one o f a s e r i e s on c o a s t a l a q u a t i c organisms p r i n c i p a l l y f i s h o f s p o r t commercial o r e c o l o g i c a l importance The p r o f i l e s a r e designed t o p r o v i d e c o a s t a l managers eng ineers and b i o l o g i s t s w i t h a b r i e f comprehensive ske t ch o f t h e b i o l o g i c a l c h a r a c t e r i s t i c s and env i ronmenta l requi rements o f t h e spec ies and t o desc r i be how popu la t i ons o f t h e spec ies may be expected t o r e a c t t o env i ronmenta l changes caused by c o a s t a l development Each p r o f i l e has s e c t i o n s on taxonomy 1 i f e h i s t o r y e c o l o g i c a l r o l e env i ronmenta l r e q u i rements and economic impor tance i f app l i c a b l e A t h r e e - r i ng b i n d e r i s used f o r t h i s s e r i e s so t h a t new p r o f i l e s can be added as t hey a r e prepared T h i s p r o j e c t i s j o i n t l y p lanned and f inanced by t h e US Army Corps o f Engineers and t h e US F i s h and W i l d l i f e Serv ice

Suggest ions o r ques t i ons r e g a r d i n g t h i s r e p o r t shou ld be d i r e c t e d t o one of t h e f o l l o w i n g addresses

I n f o r m a t i o n T r a n s f e r Spec ia l i s t N a t i o n a l Wetlands Research Center US F i s h and W i l d l i f e Se rv i ce NASA-Sl ide l l Computer Complex 1010 Gause Bou levard S l i d e l 1 LA 70458

U S Army Engineer Waterways Experiment S t a t i o n A t t e n t i o n WESER-C Pos t O f f i c e Box 631 V icksburg MS 39180

CONVERSION TABLE

M e t r i c t o US Customary

Mu1 t i p l y

m i l l i m e t e r s (mm) cen t imete rs (cm) meters (m) meters (m) k i l omete rs (km) k i 1 ometers ( km)

square meters (m2) 1076 square k i lomete rs (km2) 03861 hectares (ha) 2471

l i t e r s (1) cub ic meters (m3) cub ic meters (m3)

m i 11 igrams (mg) grams (g) k i 1 ograms (kg) m e t r i c tons (t) m e t r i c tons (t)

k i l o c a l o r i e s ( k c a l ) Ce ls ius degrees ( O C )

US Customary t o M e t r i c

inches 2540 inches 254 f e e t ( f t ) 03048 fathoms 1829 s t a t u t e m i l e s ( m i ) 1609 n a u t i c a l m i l e s (nmi) 1852

square f e e t ( f t2) square m i l e s ( m i 2 ) acres

g a l l o n s ( g a l ) cub ic f e e t ( f t 3 ) a c r e - f e e t

ounces (oz) ounces (oz) pounds ( l b ) pounds ( l b ) s h o r t tons ( ton )

B r i t i s h thermal u n i t s (Btu) Fahrenhei t degrees (OF)

To Obta in

inches inches f e e t fathoms s t a t u t e m i l e s n a u t i c a l m i l e s

square f e e t square m i l e s acres

g a l l o n s cub ic f e e t acre- f e e t

ounces ounces pounds pounds s h o r t tons

B r i t i s h thermal u n i t s Fahrenhei t degrees

m i l l i m e t e r s cen t imete rs meters meters k i l omete rs k i 1 ometers

square meters square k i lometers hectares

1 i t e r s cub ic meters cub ic meters

m i l l i g r a m s grams k i lograms m e t r i c tons m e t r i c tons

k i l o c a l o r i e s Ce ls ius degrees

Page

PREFACE ii i CONVERSION FACTORS i v ACKNOWLEDGMENTS v i

NOMENCLATURETAXONOMYRANGE 1 Sum~nerF lounder 1

W i n t e r F l o u n d e r 2 MORPHOLOGYIDENTIFICATON AIDS 2

Summer F lounder 2 a i n t e r F l o u n d e r 2

REASONFORINCLUSIONINSERIES 2 LIFE HISTORY 4

R e p r o d u c t i v e P h y s i o l o g y l S t r a t e g y 4 Spawning 4

Eggs 5 La rvae 5 J u v e n i l e s 6 A d u l t s 6

GROWTH CHARACTERISTICS 9 Growth Rates and Length-Weight R e l a t i o n s h i p s 9

THE FISHERY 1 0 Commercial F i s h e r i e s 1 0 R e c r e a t i o n a l F i s h e r i e s 10 Popul a t i o n Dynamics 10

ECOLOGICALROLE 11 Food H a b i t s 11 Feeding g e h a v i o r 11 P a r a s i t e s 11

ENVIRONMENTAL REQUIREMENTS 1 2 Temperature and Sal i n i t y 1 2 P o l l u t i o n 12

LITERATURE CITED 1 5

ACKNOWL EDmENTS

We would l i k e t o express our s i n c e r e thanks t o Dorothy Wright f o r t y p i n g t h i s manuscr ip t Also we would l i k e t o thank D r L a r r y Ray Grimes f o r t e c h n i c a l ass i s t ance and adv ice We a l so thank John Musick o f t h e V i r g i n i a I n s t i t u t e o f Mar ine Science and Paul S c a r l e t t o f t h e New Jersey D i v i s i o n o f F i s h and Game f o r r e v i e w i n g t h e r e p o r t

Figure 1 A Summer f lounder (Powell 1974) B Winter f lounder ( M a r t i n and Drewry 1978)

SUMMER AND WINTER FLOUNDER

Summer F l ounder

S c i e n t i f i c name P a r a l i c h t h y s d e n t a t u s

P r e f e r r e d common name Summer f l o u n a e r ( F i g u r e 1 A )

Othe r common names F lounder f l u k e p l a i c e f i s h p l a i c e p l a i s e s p l a i c e c h i c k e n ha1 i b u t f l o u n d e r o f New York common f 1 ounder b r a i l

t u r b o t f l a t f i s h l o n g t o o t h e d f l o u n - d e r

C lass Os te i ch thyes Order P leu ronec t i f o rmes Fami ly Both idae Geographic range The summer f l o u n d e r

p r e f 5 r s e s t u a r i n e and s h e l f wa te rs o f t h e A t l a n t i c Ocean I t i s found b e t w e e n N o v a S c o t i d a n d t h e s o u t h e a s t e r n c o a s t o f F l o r i d a b u t i s m o s t a b u n d a n t f r o m C a p e Cod M a s s a c h u s e t t s t o Cape H a t t e r a s N o r t h Caro l i na ( t i i 1 debrand and Schroeder 1928) D i s t r i b u t i o n i n

t h e m i d - A t l a n t i c r eg ion i s shown i n F igu re 2

W in te r F lounder

j c i e n t i f i c name P s e u d o ~ l e u r o n e c t e s ameriranus

P r e t e r r e d common name h i n t e r f 1 ounder ( F i g u r e 1 6 )

Other common names F l a t f i s h S l a c k b a c k Georges Bank f l o u n d e r 1 emon s o l e f l ounaer so le rough f 1 o u n u e r p l i e r o u g e c a r r e l e t ha1 i but ho l i but dab

C lass O s t e i c h t h y e s Order P l e u r o n e c t i f o r m e s F a m i l y P l e u r o n e c t i d a e Geographic range The w i n t e r f l o u n d e r

h a s a b road range o c c u r r i n g f rom B u t t l e Harbor and Windy T i c k l e Labrador t o Beaufor t No r th Caro l ina b u t i s most common i n es tua r i es between t h e G u l f o f S t Lawrence and Chesapeake Bay D i s t r i b u t i o n i n t h e M i d - A t l a n t i c Region i s shown i n F igu re 2

M O R P H O L O G Y I D E N T ~ F I C A T I O N AIDS

Summer F lounder

The boay 3 f t h e summer f l o l ~ n d e r i s l a t e r a l l y f l a t t e n e a a m a r g i i ~ o f t h e p r e o p e r c l e i s f r e e and t h e eyes a r e on t h e l e f t s i d e The bases c f b o t h p e l v i c f i n s a r e s h o r t The o c u l a r s i d e o f t h e f i s h ranges f rom t a n t o d a r k brown and has riunierous o c e l l a t e d spo ts F i v e p rominen t s p o t s are ar ranged i n two t r i a n g l e s w i t h a common apex on t h e l a t e r a l 1ine h o w e v e r t h i s c o n f i g u r a t i o n i s genera l 1 y 1 ack ing i n 1 a r g e r specimens The f i s h a r e a b l e t o b l e n d i n t o t h e i r background b y adap t ing t o t h e t e x t u r e and c o l o r o f t h e s u b s t r a t e on which t h e y l i v e

M e r i s t i c c h a r a c t e r i s t i c s Dorsal rays 80-98 anal rays 63-78 pec to ra l rays 10-13 ver tebrae 40-43 (Smith and Da iber 1977) g i l l r a k e r s on lower l i m b o f f i r s t arch 14-19 Average head l e n g t h and average upper

jaw l e n g t h a re conta ined 396 and 205 t imes r e s p e c t i v e l y i n s tandard 1 ength (SL) (Hi ldebrand and Schroeder 1928) The sca les a re c teno id Late p o s t l arvae o f summer f l ounde r have a we1 1 -de f ined band o f b l a c k pigment a long t h e a n t e r i o r t w o - t h i r d s o f t h e anal f i n and a s i m i l a r band along t h e a n t e r i o r f o u r - f i f t h s o f t h e dorsa l f i n (F igu re 3d) which a re l a c k i n g i n t he southern f l ounde r (Para1 i ch thvs le thos t iqma) and t h e g u l f f l ounde r (P a1 b i q u t t a ) Summer f l ounde r p o s t l arvae t y p i c a l l y have 40-42 t o t a l ver tebrae whi 1 e southern f l ounde r pos t l a r vae have 37 o r 38 and g u l f f l ounde r pos t l a r vae have 36-38 Summer f l ounde r p o s t l arvae have 81 -94 dorsa l r ays and 61-74 anal rays w h i l e gu l f f l ounde r p o s t l arvae have 72-82 dorsa l r ays and 53-63 anal r ays (Deubl e r 1958) Winter Flounder

The w i n t e r f l ounde r s body i s ovate and l a t e r a l l y compressed The eyes a re on t h e r i g h t side separated by a narrow scaled r i dge t he upper eye i s near t h e edge o f t h e head The mouth i s o f moderate s i z e and t h e l e n g t h o f t h e m a x i l l a r y on t h e b l i n d s i d e i s l e s s than o n e - t h i r d t h a t o f t h e head Winter f l ounde r a re 01 i v e green t o reddish-brown i n c o l o r and sometimes have a few r u s t y spots The l a t e r a l 1 i n e i s n e a r l y s t r a i g h t The dorsa l f i n o r i g i n a t e s oppos i te t h e forward edge o f t h e eye and i s o f n e a r l y equal h e i g h t throughout i t s 1 ength

Mer i s t i c c h a r a c t e r i s t i c s Dorsal r ays 56-81 anal r a y s 47-54 pec to ra l r ays 10-11 g i l l r a k e r s on lower l i m b o f f i r s t arch 7-8 ver tebrae 36 Average head l e n g t h i s 40 cm (Hi ldebrand and Schroeder 1928 P ie r ce and Howe 1977) The scales a re c teno id

REASON FOR INCLUSION I N SERIES

The summer f l ounde r i s an impor tan t commerci a1 and r e c r e a t i o n a l

NEW YORK

PHILADELPHIA

ATLANTIC OCEAN

M I L E S

K I L O M E T E R S

Summer flounder

Figure 2 D i s t r i b u t i o n o f t h e Summer and Winter f lounder i n t h e mid-At lant ic reg ion

3

species along the A t l a n t i c seaboard o f the Uni ted States and i s the major r e c r e a t i o n a l l y caught f lounder o f the mid-At1 a n t i c inshore waters There are th ree major commercial f i s h e r i e s the inshore summer f i she ry the o f f sho re w i n t e r f i she ry and a f a l l and w i n t e r t raw l f i she ry i n s i d e the 20-fathom (36-m) contour t h a t developed on the V i r g i n i a and North Carol ina coast i n the 1960s (Hi 1 debrand and Schroeder 1928 Scar1 e t t 1981)

weight f o r w i n t e r f lounder was as f o l l ows I

where W i s weight i n grams

South A t l a n t i c B igh t (Smith 1973) Adu l t summer f lounder move back inshore t o es tua r ies o r coastal waters i n the w i n t e r and spr ing (Wi lk e t a l 1980)

LIFE HISTORY SD awn i ng --

R e p r o d u c t i v e P h y s i o l o g y S t r a t e g y

A d u l t female summer f l o u n d e r on t h e a v e r a g e a r e 6 0 mm l o n g e r ( i n t o t a l length TL) than males a t f i r s t at ta inment o f sexual m a t u r i t y i n the Mid-At1 a n t i c B igh t (Morse 1981) The summer f lounder appears t o become sexua l ly mature by the age o f I 1 (Morse 1981) Gonads o f summer f lounder r ipened from mid-August through November i n the Delaware Bay the f i s h moved o f f sho re t o spawn i n the w i n t e r (Smith and Daiber 1977) Morse (1981) repor ted t h a t summer f lounder have a p ro t rac ted spawning season o f v a r i a b l e du ra t i on w i t h e a r l y maturat ion h igh fecundi ty s e r i a l spawning and ex tens ive migra t ions across the con t inen ta l she l f L i f e h i s t o r y parameters are determined by l o c a l genet ic and environmental fac tors

The number o f maturing ova i n summer f lounder i s h i g h l y co r re la ted w i t h weight and length F ish i n the Mid-At1 a n t i c Region between 366 and 680 mm TL have an est imated 046 t o 419 m i l l i o n ova (Morse 1981)

Total egg count o f w in te r f lounder ranged from 0435 m i 11 i o n f o r an age-I11 f i s h t o 3329 m i l l i o n eggs f o r an age-V f i s h captured o f f Massachusetts (Topp 1968) The reg ress ion equat ion f o r t he r e l a t i o n s h i p o f f ecund i t y t o f i s h

I n t h e S o u t h A t l a n t i c B i g h t spawning t i m e s and h a b i t a t s o f summer f 1 ounder a r e p o o r l y documented Based o n c o l l e c t i o n s o f n e w l y h a t c h e d l a r v a e commerc ia l c a t c h r a t e s and genera l i z e d c o a s t a l and she1 f t r a w l i n g s u r v e y s seasonal m i g r a t i o n p a t t e r n s o f a d u l t f i s h have been deduced I t i s known t h a t summer f l o u n d e r m i g r a t e o f f s h o r e d u r i n g c o o l e r months I n l a t e f a l l w i n t e r o r e a r l y s p r i n g t h e y spawn near t h e bo t tom o f s h e l f wa te rs 30-200 m deep The g e n e t i c a l l y d i s t i n c t p o p u l a t i o n s n o r t h and sou th o f C a p e H a t t e r a s m a y b e h a v e d i f f e r e n t l y

Between Cape Cod P~assachuset ts and Cape L o o k o u t N o r t h C a r o l i n a spawning o f summer f l o u n d e r began i n September (Smi th 1973) I n t h e s u r v e y b y S m i t h ( 1 9 7 3 ) spawning c o n t i n u e d t h r o u g h December i n t h e n o r t h e r n p a r t and t h r o u g h F e b r u a r y t o t h e south Spawn ing i n t h e Mid-At1 a n t i c Region c o n t i n u e s i n t o Februa ry and March i n some y e a r s and p r o b a b l y b e g i n s n o r t h o f C h e s a p e a k e Bay and p r o g r e s s e s southward i n a c y c l e t h a t ends i n t h e South A t l a n t i c B i g h t ( S m i t h 1973) A d u l t summer f 1 o u n d e r move b a c k i n s h o r e t o e s t u a r i e s o r c o a s t a l wa te rs i n t h e w i n t e r and s p r i n g ( W i l k e t a l 1 9 8 0 )

Spawning t imes o f the w i n t e r f lounder are var iab le l i k e those o f the summer f lounder spawning occurs f i r s t i n the southern p a r t o f the

range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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SllF~lvlER AND WINTER FLOUNDER

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r i o r t h C a r o l i n a S t a t e U n i v e r s i t y R a l e i g h NC 27695

and

D a v i d K o r a n US F i s h and W i l a l i f e S e r v i c e

N a t i o n a l Wet l ands R e s e a r c h C e n t e r 1 0 1 0 Gause B o u l e v a r d

S l i d e l l LA 70458

P r o j e c t Manager Edward P e n d l e t o n

US F i s h and W i l d l i f e S e r v i c e N a t i o n a l Wet l ands R e s e a r c h C e n t e r

1 0 1 0 Gause B o u l e v a r d S l i d e l l LA 70458

P e r f o r m e d f o r

C o a s t a l E c o l o g y Group Waterways E x p e r i m e n t S t a t i o n US Army C o r p s o f E n g i n e e r s

V i c k s b u r g MS 39180

and

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N a t i o n a l W e t l ands R e s e a r c h C e n t e r W a s h i n g t o n DC 20240

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T h i s p r o f i l e s h o u l d b e c i t e d as f o l i o w s

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PREFACE

T h i s spec ies p r o f i l e i s one o f a s e r i e s on c o a s t a l a q u a t i c organisms p r i n c i p a l l y f i s h o f s p o r t commercial o r e c o l o g i c a l importance The p r o f i l e s a r e designed t o p r o v i d e c o a s t a l managers eng ineers and b i o l o g i s t s w i t h a b r i e f comprehensive ske t ch o f t h e b i o l o g i c a l c h a r a c t e r i s t i c s and env i ronmenta l requi rements o f t h e spec ies and t o desc r i be how popu la t i ons o f t h e spec ies may be expected t o r e a c t t o env i ronmenta l changes caused by c o a s t a l development Each p r o f i l e has s e c t i o n s on taxonomy 1 i f e h i s t o r y e c o l o g i c a l r o l e env i ronmenta l r e q u i rements and economic impor tance i f app l i c a b l e A t h r e e - r i ng b i n d e r i s used f o r t h i s s e r i e s so t h a t new p r o f i l e s can be added as t hey a r e prepared T h i s p r o j e c t i s j o i n t l y p lanned and f inanced by t h e US Army Corps o f Engineers and t h e US F i s h and W i l d l i f e Serv ice

Suggest ions o r ques t i ons r e g a r d i n g t h i s r e p o r t shou ld be d i r e c t e d t o one of t h e f o l l o w i n g addresses

I n f o r m a t i o n T r a n s f e r Spec ia l i s t N a t i o n a l Wetlands Research Center US F i s h and W i l d l i f e Se rv i ce NASA-Sl ide l l Computer Complex 1010 Gause Bou levard S l i d e l 1 LA 70458

U S Army Engineer Waterways Experiment S t a t i o n A t t e n t i o n WESER-C Pos t O f f i c e Box 631 V icksburg MS 39180

CONVERSION TABLE

M e t r i c t o US Customary

Mu1 t i p l y

m i l l i m e t e r s (mm) cen t imete rs (cm) meters (m) meters (m) k i l omete rs (km) k i 1 ometers ( km)

square meters (m2) 1076 square k i lomete rs (km2) 03861 hectares (ha) 2471

l i t e r s (1) cub ic meters (m3) cub ic meters (m3)

m i 11 igrams (mg) grams (g) k i 1 ograms (kg) m e t r i c tons (t) m e t r i c tons (t)

k i l o c a l o r i e s ( k c a l ) Ce ls ius degrees ( O C )

US Customary t o M e t r i c

inches 2540 inches 254 f e e t ( f t ) 03048 fathoms 1829 s t a t u t e m i l e s ( m i ) 1609 n a u t i c a l m i l e s (nmi) 1852

square f e e t ( f t2) square m i l e s ( m i 2 ) acres

g a l l o n s ( g a l ) cub ic f e e t ( f t 3 ) a c r e - f e e t

ounces (oz) ounces (oz) pounds ( l b ) pounds ( l b ) s h o r t tons ( ton )

B r i t i s h thermal u n i t s (Btu) Fahrenhei t degrees (OF)

To Obta in

inches inches f e e t fathoms s t a t u t e m i l e s n a u t i c a l m i l e s

square f e e t square m i l e s acres

g a l l o n s cub ic f e e t acre- f e e t

ounces ounces pounds pounds s h o r t tons

B r i t i s h thermal u n i t s Fahrenhei t degrees

m i l l i m e t e r s cen t imete rs meters meters k i l omete rs k i 1 ometers

square meters square k i lometers hectares

1 i t e r s cub ic meters cub ic meters

m i l l i g r a m s grams k i lograms m e t r i c tons m e t r i c tons

k i l o c a l o r i e s Ce ls ius degrees

Page

PREFACE ii i CONVERSION FACTORS i v ACKNOWLEDGMENTS v i

NOMENCLATURETAXONOMYRANGE 1 Sum~nerF lounder 1

W i n t e r F l o u n d e r 2 MORPHOLOGYIDENTIFICATON AIDS 2

Summer F lounder 2 a i n t e r F l o u n d e r 2

REASONFORINCLUSIONINSERIES 2 LIFE HISTORY 4

R e p r o d u c t i v e P h y s i o l o g y l S t r a t e g y 4 Spawning 4

Eggs 5 La rvae 5 J u v e n i l e s 6 A d u l t s 6

GROWTH CHARACTERISTICS 9 Growth Rates and Length-Weight R e l a t i o n s h i p s 9

THE FISHERY 1 0 Commercial F i s h e r i e s 1 0 R e c r e a t i o n a l F i s h e r i e s 10 Popul a t i o n Dynamics 10

ECOLOGICALROLE 11 Food H a b i t s 11 Feeding g e h a v i o r 11 P a r a s i t e s 11

ENVIRONMENTAL REQUIREMENTS 1 2 Temperature and Sal i n i t y 1 2 P o l l u t i o n 12

LITERATURE CITED 1 5

ACKNOWL EDmENTS

We would l i k e t o express our s i n c e r e thanks t o Dorothy Wright f o r t y p i n g t h i s manuscr ip t Also we would l i k e t o thank D r L a r r y Ray Grimes f o r t e c h n i c a l ass i s t ance and adv ice We a l so thank John Musick o f t h e V i r g i n i a I n s t i t u t e o f Mar ine Science and Paul S c a r l e t t o f t h e New Jersey D i v i s i o n o f F i s h and Game f o r r e v i e w i n g t h e r e p o r t

Figure 1 A Summer f lounder (Powell 1974) B Winter f lounder ( M a r t i n and Drewry 1978)

SUMMER AND WINTER FLOUNDER

Summer F l ounder

S c i e n t i f i c name P a r a l i c h t h y s d e n t a t u s

P r e f e r r e d common name Summer f l o u n a e r ( F i g u r e 1 A )

Othe r common names F lounder f l u k e p l a i c e f i s h p l a i c e p l a i s e s p l a i c e c h i c k e n ha1 i b u t f l o u n d e r o f New York common f 1 ounder b r a i l

t u r b o t f l a t f i s h l o n g t o o t h e d f l o u n - d e r

C lass Os te i ch thyes Order P leu ronec t i f o rmes Fami ly Both idae Geographic range The summer f l o u n d e r

p r e f 5 r s e s t u a r i n e and s h e l f wa te rs o f t h e A t l a n t i c Ocean I t i s found b e t w e e n N o v a S c o t i d a n d t h e s o u t h e a s t e r n c o a s t o f F l o r i d a b u t i s m o s t a b u n d a n t f r o m C a p e Cod M a s s a c h u s e t t s t o Cape H a t t e r a s N o r t h Caro l i na ( t i i 1 debrand and Schroeder 1928) D i s t r i b u t i o n i n

t h e m i d - A t l a n t i c r eg ion i s shown i n F igu re 2

W in te r F lounder

j c i e n t i f i c name P s e u d o ~ l e u r o n e c t e s ameriranus

P r e t e r r e d common name h i n t e r f 1 ounder ( F i g u r e 1 6 )

Other common names F l a t f i s h S l a c k b a c k Georges Bank f l o u n d e r 1 emon s o l e f l ounaer so le rough f 1 o u n u e r p l i e r o u g e c a r r e l e t ha1 i but ho l i but dab

C lass O s t e i c h t h y e s Order P l e u r o n e c t i f o r m e s F a m i l y P l e u r o n e c t i d a e Geographic range The w i n t e r f l o u n d e r

h a s a b road range o c c u r r i n g f rom B u t t l e Harbor and Windy T i c k l e Labrador t o Beaufor t No r th Caro l ina b u t i s most common i n es tua r i es between t h e G u l f o f S t Lawrence and Chesapeake Bay D i s t r i b u t i o n i n t h e M i d - A t l a n t i c Region i s shown i n F igu re 2

M O R P H O L O G Y I D E N T ~ F I C A T I O N AIDS

Summer F lounder

The boay 3 f t h e summer f l o l ~ n d e r i s l a t e r a l l y f l a t t e n e a a m a r g i i ~ o f t h e p r e o p e r c l e i s f r e e and t h e eyes a r e on t h e l e f t s i d e The bases c f b o t h p e l v i c f i n s a r e s h o r t The o c u l a r s i d e o f t h e f i s h ranges f rom t a n t o d a r k brown and has riunierous o c e l l a t e d spo ts F i v e p rominen t s p o t s are ar ranged i n two t r i a n g l e s w i t h a common apex on t h e l a t e r a l 1ine h o w e v e r t h i s c o n f i g u r a t i o n i s genera l 1 y 1 ack ing i n 1 a r g e r specimens The f i s h a r e a b l e t o b l e n d i n t o t h e i r background b y adap t ing t o t h e t e x t u r e and c o l o r o f t h e s u b s t r a t e on which t h e y l i v e

M e r i s t i c c h a r a c t e r i s t i c s Dorsal rays 80-98 anal rays 63-78 pec to ra l rays 10-13 ver tebrae 40-43 (Smith and Da iber 1977) g i l l r a k e r s on lower l i m b o f f i r s t arch 14-19 Average head l e n g t h and average upper

jaw l e n g t h a re conta ined 396 and 205 t imes r e s p e c t i v e l y i n s tandard 1 ength (SL) (Hi ldebrand and Schroeder 1928) The sca les a re c teno id Late p o s t l arvae o f summer f l ounde r have a we1 1 -de f ined band o f b l a c k pigment a long t h e a n t e r i o r t w o - t h i r d s o f t h e anal f i n and a s i m i l a r band along t h e a n t e r i o r f o u r - f i f t h s o f t h e dorsa l f i n (F igu re 3d) which a re l a c k i n g i n t he southern f l ounde r (Para1 i ch thvs le thos t iqma) and t h e g u l f f l ounde r (P a1 b i q u t t a ) Summer f l ounde r p o s t l arvae t y p i c a l l y have 40-42 t o t a l ver tebrae whi 1 e southern f l ounde r pos t l a r vae have 37 o r 38 and g u l f f l ounde r pos t l a r vae have 36-38 Summer f l ounde r p o s t l arvae have 81 -94 dorsa l r ays and 61-74 anal rays w h i l e gu l f f l ounde r p o s t l arvae have 72-82 dorsa l r ays and 53-63 anal r ays (Deubl e r 1958) Winter Flounder

The w i n t e r f l ounde r s body i s ovate and l a t e r a l l y compressed The eyes a re on t h e r i g h t side separated by a narrow scaled r i dge t he upper eye i s near t h e edge o f t h e head The mouth i s o f moderate s i z e and t h e l e n g t h o f t h e m a x i l l a r y on t h e b l i n d s i d e i s l e s s than o n e - t h i r d t h a t o f t h e head Winter f l ounde r a re 01 i v e green t o reddish-brown i n c o l o r and sometimes have a few r u s t y spots The l a t e r a l 1 i n e i s n e a r l y s t r a i g h t The dorsa l f i n o r i g i n a t e s oppos i te t h e forward edge o f t h e eye and i s o f n e a r l y equal h e i g h t throughout i t s 1 ength

Mer i s t i c c h a r a c t e r i s t i c s Dorsal r ays 56-81 anal r a y s 47-54 pec to ra l r ays 10-11 g i l l r a k e r s on lower l i m b o f f i r s t arch 7-8 ver tebrae 36 Average head l e n g t h i s 40 cm (Hi ldebrand and Schroeder 1928 P ie r ce and Howe 1977) The scales a re c teno id

REASON FOR INCLUSION I N SERIES

The summer f l ounde r i s an impor tan t commerci a1 and r e c r e a t i o n a l

NEW YORK

PHILADELPHIA

ATLANTIC OCEAN

M I L E S

K I L O M E T E R S

Summer flounder

Figure 2 D i s t r i b u t i o n o f t h e Summer and Winter f lounder i n t h e mid-At lant ic reg ion

3

species along the A t l a n t i c seaboard o f the Uni ted States and i s the major r e c r e a t i o n a l l y caught f lounder o f the mid-At1 a n t i c inshore waters There are th ree major commercial f i s h e r i e s the inshore summer f i she ry the o f f sho re w i n t e r f i she ry and a f a l l and w i n t e r t raw l f i she ry i n s i d e the 20-fathom (36-m) contour t h a t developed on the V i r g i n i a and North Carol ina coast i n the 1960s (Hi 1 debrand and Schroeder 1928 Scar1 e t t 1981)

weight f o r w i n t e r f lounder was as f o l l ows I

where W i s weight i n grams

South A t l a n t i c B igh t (Smith 1973) Adu l t summer f lounder move back inshore t o es tua r ies o r coastal waters i n the w i n t e r and spr ing (Wi lk e t a l 1980)

LIFE HISTORY SD awn i ng --

R e p r o d u c t i v e P h y s i o l o g y S t r a t e g y

A d u l t female summer f l o u n d e r on t h e a v e r a g e a r e 6 0 mm l o n g e r ( i n t o t a l length TL) than males a t f i r s t at ta inment o f sexual m a t u r i t y i n the Mid-At1 a n t i c B igh t (Morse 1981) The summer f lounder appears t o become sexua l ly mature by the age o f I 1 (Morse 1981) Gonads o f summer f lounder r ipened from mid-August through November i n the Delaware Bay the f i s h moved o f f sho re t o spawn i n the w i n t e r (Smith and Daiber 1977) Morse (1981) repor ted t h a t summer f lounder have a p ro t rac ted spawning season o f v a r i a b l e du ra t i on w i t h e a r l y maturat ion h igh fecundi ty s e r i a l spawning and ex tens ive migra t ions across the con t inen ta l she l f L i f e h i s t o r y parameters are determined by l o c a l genet ic and environmental fac tors

The number o f maturing ova i n summer f lounder i s h i g h l y co r re la ted w i t h weight and length F ish i n the Mid-At1 a n t i c Region between 366 and 680 mm TL have an est imated 046 t o 419 m i l l i o n ova (Morse 1981)

Total egg count o f w in te r f lounder ranged from 0435 m i 11 i o n f o r an age-I11 f i s h t o 3329 m i l l i o n eggs f o r an age-V f i s h captured o f f Massachusetts (Topp 1968) The reg ress ion equat ion f o r t he r e l a t i o n s h i p o f f ecund i t y t o f i s h

I n t h e S o u t h A t l a n t i c B i g h t spawning t i m e s and h a b i t a t s o f summer f 1 ounder a r e p o o r l y documented Based o n c o l l e c t i o n s o f n e w l y h a t c h e d l a r v a e commerc ia l c a t c h r a t e s and genera l i z e d c o a s t a l and she1 f t r a w l i n g s u r v e y s seasonal m i g r a t i o n p a t t e r n s o f a d u l t f i s h have been deduced I t i s known t h a t summer f l o u n d e r m i g r a t e o f f s h o r e d u r i n g c o o l e r months I n l a t e f a l l w i n t e r o r e a r l y s p r i n g t h e y spawn near t h e bo t tom o f s h e l f wa te rs 30-200 m deep The g e n e t i c a l l y d i s t i n c t p o p u l a t i o n s n o r t h and sou th o f C a p e H a t t e r a s m a y b e h a v e d i f f e r e n t l y

Between Cape Cod P~assachuset ts and Cape L o o k o u t N o r t h C a r o l i n a spawning o f summer f l o u n d e r began i n September (Smi th 1973) I n t h e s u r v e y b y S m i t h ( 1 9 7 3 ) spawning c o n t i n u e d t h r o u g h December i n t h e n o r t h e r n p a r t and t h r o u g h F e b r u a r y t o t h e south Spawn ing i n t h e Mid-At1 a n t i c Region c o n t i n u e s i n t o Februa ry and March i n some y e a r s and p r o b a b l y b e g i n s n o r t h o f C h e s a p e a k e Bay and p r o g r e s s e s southward i n a c y c l e t h a t ends i n t h e South A t l a n t i c B i g h t ( S m i t h 1973) A d u l t summer f 1 o u n d e r move b a c k i n s h o r e t o e s t u a r i e s o r c o a s t a l wa te rs i n t h e w i n t e r and s p r i n g ( W i l k e t a l 1 9 8 0 )

Spawning t imes o f the w i n t e r f lounder are var iab le l i k e those o f the summer f lounder spawning occurs f i r s t i n the southern p a r t o f the

range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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Howe AB and PG Coates 1975 W i n t e r f l o u n d e r movements growth and m o r t a l i t y o f f P l a s s a c h u s e t t s Trans Am F i s h Soc 10413-29

Howe AB PG C o a t e s and DE P i e r c e 1976 W i n t e r f l o u n d e r

e s t u a r i n e y e a r - c l ass abundance m o r t a l i t y and r e c r u i t m e n t Trans Am F i s h Soc 105647-657

I t z k o w i t z N and JR S c h u b e l 1983 To1 e r a n c e o f f i v e - d a y - o l d w i n t e r f l o u n d e r pseudopl eu ronec tes americanus 1 arvae t o thermal shock US N a t l Mar F i s h Serv F i s h B u l l 81913-916

I t z k o w i t z N JR S c h u b e l and PMJ Woodhead 1983 R e s ~ o n s e s o f summer f l o u n d e r P a r a l i k h t h y s den ta tus embryos t o thermal shock Env i ron B i o l F i s h e s 8125-135

J e f f r i e s HP and W C Johnson 1974 S e a s o n a l d i s t r i b u t i o n s o f b o t t o m f i s h e s i n t h e N a r r a g a n s e t t 3ay area seven-year v a r i a t i o n s n t h e a ~ u n d a n c e o f w i n t e r f l o u n d e r (Pseudopl eu ronec tes americanus) J F i s h Res 3oard Can 311057- i066

J o h n s I WH H o w e l l and S K l e i n - F a c P h e e 1 9 8 1 Y o l k u t i l i z a t i o n and g rowth t o y o l k sac a b s o r p t i o n i n summer f l o u n d e r ( P a r a l i c h t h y s d e n t a t u s ) l a r v a e a t c o n s t a n t and c y c l i c tempera tu res K a r B i o l ( B e r l ) 63301-330

Kennedy VS and 3H S t e e l e 1971 T h e w i n t e r f l o u n d e r ( P s e u d o p l eu ronec tes americanus) i n L o n g P o n d C o n c e p t i o n B a y Wewfoundl and J F i s h Res Board Can 281153-1165

Keup L and J aay less 1964 F i s h d i s t r i b u t i o n a t v a r y i n g s a l i n i t i e s i n N e u s e R i v e r b a s i n N o r t h Caro l i n a Chesapeake S c i 5119- 123

L a u r e n c e G C 1975 L a b o r a t o r y g r o w t h and me tabo l i sm o f t h e w i n t e r f 1 o u n d e r P s e u d o p l e u r o n e c t e s a m e r i c a n u s f r o m h a t c h i n g t h r o u g h metamorphosis a t t h r e e tempera tu res Mar B i o l ( B e r l ) 32223-229

Lev ings CD 1974 Seasonal changes i n f e e d i n g and p a r t i c l e s e l e c t i o n b y

w i n t e r f l o u n d e r (Pseudopl eu ronec tes amer icanus) Trans Am F i s h Soc 103828-832

M a r t i n FD and GE Drewry 1978 Deve lopment of f i s h e s o f t h e Mid- A t l a n t i c B i g h t an a t l a s o f egg 1 a r v a l and juven i 1 e s tages Vol V I S t r o m a t e i d a e t h r o u g h Ogocepha l i d a e US F i s h W i l d l Serv B i o l Serv Program FWSOBS- 7812 416 pp

McCracken FD 1963 Seasonal movements o f the w in te r f lounder P s e u d o ~ l e u r o n e c t e s americanus (Walbaum) on the A t l a n t i c coast J Fish Res Board Can 20551-586

Morse W W 1981 Reproduc t i on o f t h e summer f l o u n d e r P a r a l i c h t h s d e n t a t u s ( L J d 19189-203

r i a t i o n a l Y a r i n e F i s h e r i e s S e r v i c e 1980 F i s h e r y S t a t i s t i c s o f t h e U n i t e d S t a t e s 1979 US N a t l Far F i s h Serv Cur r F i s h S t a t NO aooo

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987a F i s h e r i e s o f t h e U n i t e d S ta tes 1486 08 N a t l Mar F i s h Serv Cur r F i s h S t a t 8385

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987b Mar ine r e c r e a t i o n a l f i s h e r y s t a t i s t i c s survey A t l a n t i c and g u l f coas ts 1986 US N a t l Mar F i s h Serv Cur r F i s h S t a t 8392

O l l a BL R Wicklund and S Wilk 1969 Behavior o f winter f lounder i n a natura l h a b i t a t Trans Am Fish Soc 98717-720

O l l a BL CE Samet and AL Studholme 1972 A c t i v i t y and feeding behavior o f the summer flounder (Paral i c h t h v ~ dentatus) under c o n t r o l 1 ed 1 abora to ry conditions Fish B u l l 701127- 1136

P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

T h i s s e r i e s s h o u l d be r e f e r e n c e d as f o l l o w s

US F i s h an3 W i l d l i f e S e r v i c e 1983-1988 Spec ies p r o f i l e s l i f e h i s t o r i e s and env i ronrner i ta l r e q u i r e m e n t s o f c o a s t a l f i s h e s dnd i n v e r t e b r a t e s J S F i s h Wild1 Serv B io l Rep 82 (11) US Army Corps o f Engineers TR EL-82-4

T h i s p r o f i l e s h o u l d b e c i t e d as f o l i o w s

Grimes BH MT Hu ish JH Kerby and D Poran 1989 Spec ies p r o f i l e s l i f e h i s t o r i e s and e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s (M id -A t1 ant ic ) - -summer and w i n t e r f l o u n d e r US F i s h 4 i l d l Serv B i o l Rep 82(11112) US Army Corps o f Eng ineers TR EL-82-4 18 pp

PREFACE

T h i s spec ies p r o f i l e i s one o f a s e r i e s on c o a s t a l a q u a t i c organisms p r i n c i p a l l y f i s h o f s p o r t commercial o r e c o l o g i c a l importance The p r o f i l e s a r e designed t o p r o v i d e c o a s t a l managers eng ineers and b i o l o g i s t s w i t h a b r i e f comprehensive ske t ch o f t h e b i o l o g i c a l c h a r a c t e r i s t i c s and env i ronmenta l requi rements o f t h e spec ies and t o desc r i be how popu la t i ons o f t h e spec ies may be expected t o r e a c t t o env i ronmenta l changes caused by c o a s t a l development Each p r o f i l e has s e c t i o n s on taxonomy 1 i f e h i s t o r y e c o l o g i c a l r o l e env i ronmenta l r e q u i rements and economic impor tance i f app l i c a b l e A t h r e e - r i ng b i n d e r i s used f o r t h i s s e r i e s so t h a t new p r o f i l e s can be added as t hey a r e prepared T h i s p r o j e c t i s j o i n t l y p lanned and f inanced by t h e US Army Corps o f Engineers and t h e US F i s h and W i l d l i f e Serv ice

Suggest ions o r ques t i ons r e g a r d i n g t h i s r e p o r t shou ld be d i r e c t e d t o one of t h e f o l l o w i n g addresses

I n f o r m a t i o n T r a n s f e r Spec ia l i s t N a t i o n a l Wetlands Research Center US F i s h and W i l d l i f e Se rv i ce NASA-Sl ide l l Computer Complex 1010 Gause Bou levard S l i d e l 1 LA 70458

U S Army Engineer Waterways Experiment S t a t i o n A t t e n t i o n WESER-C Pos t O f f i c e Box 631 V icksburg MS 39180

CONVERSION TABLE

M e t r i c t o US Customary

Mu1 t i p l y

m i l l i m e t e r s (mm) cen t imete rs (cm) meters (m) meters (m) k i l omete rs (km) k i 1 ometers ( km)

square meters (m2) 1076 square k i lomete rs (km2) 03861 hectares (ha) 2471

l i t e r s (1) cub ic meters (m3) cub ic meters (m3)

m i 11 igrams (mg) grams (g) k i 1 ograms (kg) m e t r i c tons (t) m e t r i c tons (t)

k i l o c a l o r i e s ( k c a l ) Ce ls ius degrees ( O C )

US Customary t o M e t r i c

inches 2540 inches 254 f e e t ( f t ) 03048 fathoms 1829 s t a t u t e m i l e s ( m i ) 1609 n a u t i c a l m i l e s (nmi) 1852

square f e e t ( f t2) square m i l e s ( m i 2 ) acres

g a l l o n s ( g a l ) cub ic f e e t ( f t 3 ) a c r e - f e e t

ounces (oz) ounces (oz) pounds ( l b ) pounds ( l b ) s h o r t tons ( ton )

B r i t i s h thermal u n i t s (Btu) Fahrenhei t degrees (OF)

To Obta in

inches inches f e e t fathoms s t a t u t e m i l e s n a u t i c a l m i l e s

square f e e t square m i l e s acres

g a l l o n s cub ic f e e t acre- f e e t

ounces ounces pounds pounds s h o r t tons

B r i t i s h thermal u n i t s Fahrenhei t degrees

m i l l i m e t e r s cen t imete rs meters meters k i l omete rs k i 1 ometers

square meters square k i lometers hectares

1 i t e r s cub ic meters cub ic meters

m i l l i g r a m s grams k i lograms m e t r i c tons m e t r i c tons

k i l o c a l o r i e s Ce ls ius degrees

Page

PREFACE ii i CONVERSION FACTORS i v ACKNOWLEDGMENTS v i

NOMENCLATURETAXONOMYRANGE 1 Sum~nerF lounder 1

W i n t e r F l o u n d e r 2 MORPHOLOGYIDENTIFICATON AIDS 2

Summer F lounder 2 a i n t e r F l o u n d e r 2

REASONFORINCLUSIONINSERIES 2 LIFE HISTORY 4

R e p r o d u c t i v e P h y s i o l o g y l S t r a t e g y 4 Spawning 4

Eggs 5 La rvae 5 J u v e n i l e s 6 A d u l t s 6

GROWTH CHARACTERISTICS 9 Growth Rates and Length-Weight R e l a t i o n s h i p s 9

THE FISHERY 1 0 Commercial F i s h e r i e s 1 0 R e c r e a t i o n a l F i s h e r i e s 10 Popul a t i o n Dynamics 10

ECOLOGICALROLE 11 Food H a b i t s 11 Feeding g e h a v i o r 11 P a r a s i t e s 11

ENVIRONMENTAL REQUIREMENTS 1 2 Temperature and Sal i n i t y 1 2 P o l l u t i o n 12

LITERATURE CITED 1 5

ACKNOWL EDmENTS

We would l i k e t o express our s i n c e r e thanks t o Dorothy Wright f o r t y p i n g t h i s manuscr ip t Also we would l i k e t o thank D r L a r r y Ray Grimes f o r t e c h n i c a l ass i s t ance and adv ice We a l so thank John Musick o f t h e V i r g i n i a I n s t i t u t e o f Mar ine Science and Paul S c a r l e t t o f t h e New Jersey D i v i s i o n o f F i s h and Game f o r r e v i e w i n g t h e r e p o r t

Figure 1 A Summer f lounder (Powell 1974) B Winter f lounder ( M a r t i n and Drewry 1978)

SUMMER AND WINTER FLOUNDER

Summer F l ounder

S c i e n t i f i c name P a r a l i c h t h y s d e n t a t u s

P r e f e r r e d common name Summer f l o u n a e r ( F i g u r e 1 A )

Othe r common names F lounder f l u k e p l a i c e f i s h p l a i c e p l a i s e s p l a i c e c h i c k e n ha1 i b u t f l o u n d e r o f New York common f 1 ounder b r a i l

t u r b o t f l a t f i s h l o n g t o o t h e d f l o u n - d e r

C lass Os te i ch thyes Order P leu ronec t i f o rmes Fami ly Both idae Geographic range The summer f l o u n d e r

p r e f 5 r s e s t u a r i n e and s h e l f wa te rs o f t h e A t l a n t i c Ocean I t i s found b e t w e e n N o v a S c o t i d a n d t h e s o u t h e a s t e r n c o a s t o f F l o r i d a b u t i s m o s t a b u n d a n t f r o m C a p e Cod M a s s a c h u s e t t s t o Cape H a t t e r a s N o r t h Caro l i na ( t i i 1 debrand and Schroeder 1928) D i s t r i b u t i o n i n

t h e m i d - A t l a n t i c r eg ion i s shown i n F igu re 2

W in te r F lounder

j c i e n t i f i c name P s e u d o ~ l e u r o n e c t e s ameriranus

P r e t e r r e d common name h i n t e r f 1 ounder ( F i g u r e 1 6 )

Other common names F l a t f i s h S l a c k b a c k Georges Bank f l o u n d e r 1 emon s o l e f l ounaer so le rough f 1 o u n u e r p l i e r o u g e c a r r e l e t ha1 i but ho l i but dab

C lass O s t e i c h t h y e s Order P l e u r o n e c t i f o r m e s F a m i l y P l e u r o n e c t i d a e Geographic range The w i n t e r f l o u n d e r

h a s a b road range o c c u r r i n g f rom B u t t l e Harbor and Windy T i c k l e Labrador t o Beaufor t No r th Caro l ina b u t i s most common i n es tua r i es between t h e G u l f o f S t Lawrence and Chesapeake Bay D i s t r i b u t i o n i n t h e M i d - A t l a n t i c Region i s shown i n F igu re 2

M O R P H O L O G Y I D E N T ~ F I C A T I O N AIDS

Summer F lounder

The boay 3 f t h e summer f l o l ~ n d e r i s l a t e r a l l y f l a t t e n e a a m a r g i i ~ o f t h e p r e o p e r c l e i s f r e e and t h e eyes a r e on t h e l e f t s i d e The bases c f b o t h p e l v i c f i n s a r e s h o r t The o c u l a r s i d e o f t h e f i s h ranges f rom t a n t o d a r k brown and has riunierous o c e l l a t e d spo ts F i v e p rominen t s p o t s are ar ranged i n two t r i a n g l e s w i t h a common apex on t h e l a t e r a l 1ine h o w e v e r t h i s c o n f i g u r a t i o n i s genera l 1 y 1 ack ing i n 1 a r g e r specimens The f i s h a r e a b l e t o b l e n d i n t o t h e i r background b y adap t ing t o t h e t e x t u r e and c o l o r o f t h e s u b s t r a t e on which t h e y l i v e

M e r i s t i c c h a r a c t e r i s t i c s Dorsal rays 80-98 anal rays 63-78 pec to ra l rays 10-13 ver tebrae 40-43 (Smith and Da iber 1977) g i l l r a k e r s on lower l i m b o f f i r s t arch 14-19 Average head l e n g t h and average upper

jaw l e n g t h a re conta ined 396 and 205 t imes r e s p e c t i v e l y i n s tandard 1 ength (SL) (Hi ldebrand and Schroeder 1928) The sca les a re c teno id Late p o s t l arvae o f summer f l ounde r have a we1 1 -de f ined band o f b l a c k pigment a long t h e a n t e r i o r t w o - t h i r d s o f t h e anal f i n and a s i m i l a r band along t h e a n t e r i o r f o u r - f i f t h s o f t h e dorsa l f i n (F igu re 3d) which a re l a c k i n g i n t he southern f l ounde r (Para1 i ch thvs le thos t iqma) and t h e g u l f f l ounde r (P a1 b i q u t t a ) Summer f l ounde r p o s t l arvae t y p i c a l l y have 40-42 t o t a l ver tebrae whi 1 e southern f l ounde r pos t l a r vae have 37 o r 38 and g u l f f l ounde r pos t l a r vae have 36-38 Summer f l ounde r p o s t l arvae have 81 -94 dorsa l r ays and 61-74 anal rays w h i l e gu l f f l ounde r p o s t l arvae have 72-82 dorsa l r ays and 53-63 anal r ays (Deubl e r 1958) Winter Flounder

The w i n t e r f l ounde r s body i s ovate and l a t e r a l l y compressed The eyes a re on t h e r i g h t side separated by a narrow scaled r i dge t he upper eye i s near t h e edge o f t h e head The mouth i s o f moderate s i z e and t h e l e n g t h o f t h e m a x i l l a r y on t h e b l i n d s i d e i s l e s s than o n e - t h i r d t h a t o f t h e head Winter f l ounde r a re 01 i v e green t o reddish-brown i n c o l o r and sometimes have a few r u s t y spots The l a t e r a l 1 i n e i s n e a r l y s t r a i g h t The dorsa l f i n o r i g i n a t e s oppos i te t h e forward edge o f t h e eye and i s o f n e a r l y equal h e i g h t throughout i t s 1 ength

Mer i s t i c c h a r a c t e r i s t i c s Dorsal r ays 56-81 anal r a y s 47-54 pec to ra l r ays 10-11 g i l l r a k e r s on lower l i m b o f f i r s t arch 7-8 ver tebrae 36 Average head l e n g t h i s 40 cm (Hi ldebrand and Schroeder 1928 P ie r ce and Howe 1977) The scales a re c teno id

REASON FOR INCLUSION I N SERIES

The summer f l ounde r i s an impor tan t commerci a1 and r e c r e a t i o n a l

NEW YORK

PHILADELPHIA

ATLANTIC OCEAN

M I L E S

K I L O M E T E R S

Summer flounder

Figure 2 D i s t r i b u t i o n o f t h e Summer and Winter f lounder i n t h e mid-At lant ic reg ion

3

species along the A t l a n t i c seaboard o f the Uni ted States and i s the major r e c r e a t i o n a l l y caught f lounder o f the mid-At1 a n t i c inshore waters There are th ree major commercial f i s h e r i e s the inshore summer f i she ry the o f f sho re w i n t e r f i she ry and a f a l l and w i n t e r t raw l f i she ry i n s i d e the 20-fathom (36-m) contour t h a t developed on the V i r g i n i a and North Carol ina coast i n the 1960s (Hi 1 debrand and Schroeder 1928 Scar1 e t t 1981)

weight f o r w i n t e r f lounder was as f o l l ows I

where W i s weight i n grams

South A t l a n t i c B igh t (Smith 1973) Adu l t summer f lounder move back inshore t o es tua r ies o r coastal waters i n the w i n t e r and spr ing (Wi lk e t a l 1980)

LIFE HISTORY SD awn i ng --

R e p r o d u c t i v e P h y s i o l o g y S t r a t e g y

A d u l t female summer f l o u n d e r on t h e a v e r a g e a r e 6 0 mm l o n g e r ( i n t o t a l length TL) than males a t f i r s t at ta inment o f sexual m a t u r i t y i n the Mid-At1 a n t i c B igh t (Morse 1981) The summer f lounder appears t o become sexua l ly mature by the age o f I 1 (Morse 1981) Gonads o f summer f lounder r ipened from mid-August through November i n the Delaware Bay the f i s h moved o f f sho re t o spawn i n the w i n t e r (Smith and Daiber 1977) Morse (1981) repor ted t h a t summer f lounder have a p ro t rac ted spawning season o f v a r i a b l e du ra t i on w i t h e a r l y maturat ion h igh fecundi ty s e r i a l spawning and ex tens ive migra t ions across the con t inen ta l she l f L i f e h i s t o r y parameters are determined by l o c a l genet ic and environmental fac tors

The number o f maturing ova i n summer f lounder i s h i g h l y co r re la ted w i t h weight and length F ish i n the Mid-At1 a n t i c Region between 366 and 680 mm TL have an est imated 046 t o 419 m i l l i o n ova (Morse 1981)

Total egg count o f w in te r f lounder ranged from 0435 m i 11 i o n f o r an age-I11 f i s h t o 3329 m i l l i o n eggs f o r an age-V f i s h captured o f f Massachusetts (Topp 1968) The reg ress ion equat ion f o r t he r e l a t i o n s h i p o f f ecund i t y t o f i s h

I n t h e S o u t h A t l a n t i c B i g h t spawning t i m e s and h a b i t a t s o f summer f 1 ounder a r e p o o r l y documented Based o n c o l l e c t i o n s o f n e w l y h a t c h e d l a r v a e commerc ia l c a t c h r a t e s and genera l i z e d c o a s t a l and she1 f t r a w l i n g s u r v e y s seasonal m i g r a t i o n p a t t e r n s o f a d u l t f i s h have been deduced I t i s known t h a t summer f l o u n d e r m i g r a t e o f f s h o r e d u r i n g c o o l e r months I n l a t e f a l l w i n t e r o r e a r l y s p r i n g t h e y spawn near t h e bo t tom o f s h e l f wa te rs 30-200 m deep The g e n e t i c a l l y d i s t i n c t p o p u l a t i o n s n o r t h and sou th o f C a p e H a t t e r a s m a y b e h a v e d i f f e r e n t l y

Between Cape Cod P~assachuset ts and Cape L o o k o u t N o r t h C a r o l i n a spawning o f summer f l o u n d e r began i n September (Smi th 1973) I n t h e s u r v e y b y S m i t h ( 1 9 7 3 ) spawning c o n t i n u e d t h r o u g h December i n t h e n o r t h e r n p a r t and t h r o u g h F e b r u a r y t o t h e south Spawn ing i n t h e Mid-At1 a n t i c Region c o n t i n u e s i n t o Februa ry and March i n some y e a r s and p r o b a b l y b e g i n s n o r t h o f C h e s a p e a k e Bay and p r o g r e s s e s southward i n a c y c l e t h a t ends i n t h e South A t l a n t i c B i g h t ( S m i t h 1973) A d u l t summer f 1 o u n d e r move b a c k i n s h o r e t o e s t u a r i e s o r c o a s t a l wa te rs i n t h e w i n t e r and s p r i n g ( W i l k e t a l 1 9 8 0 )

Spawning t imes o f the w i n t e r f lounder are var iab le l i k e those o f the summer f lounder spawning occurs f i r s t i n the southern p a r t o f the

range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

PREFACE

T h i s spec ies p r o f i l e i s one o f a s e r i e s on c o a s t a l a q u a t i c organisms p r i n c i p a l l y f i s h o f s p o r t commercial o r e c o l o g i c a l importance The p r o f i l e s a r e designed t o p r o v i d e c o a s t a l managers eng ineers and b i o l o g i s t s w i t h a b r i e f comprehensive ske t ch o f t h e b i o l o g i c a l c h a r a c t e r i s t i c s and env i ronmenta l requi rements o f t h e spec ies and t o desc r i be how popu la t i ons o f t h e spec ies may be expected t o r e a c t t o env i ronmenta l changes caused by c o a s t a l development Each p r o f i l e has s e c t i o n s on taxonomy 1 i f e h i s t o r y e c o l o g i c a l r o l e env i ronmenta l r e q u i rements and economic impor tance i f app l i c a b l e A t h r e e - r i ng b i n d e r i s used f o r t h i s s e r i e s so t h a t new p r o f i l e s can be added as t hey a r e prepared T h i s p r o j e c t i s j o i n t l y p lanned and f inanced by t h e US Army Corps o f Engineers and t h e US F i s h and W i l d l i f e Serv ice

Suggest ions o r ques t i ons r e g a r d i n g t h i s r e p o r t shou ld be d i r e c t e d t o one of t h e f o l l o w i n g addresses

I n f o r m a t i o n T r a n s f e r Spec ia l i s t N a t i o n a l Wetlands Research Center US F i s h and W i l d l i f e Se rv i ce NASA-Sl ide l l Computer Complex 1010 Gause Bou levard S l i d e l 1 LA 70458

U S Army Engineer Waterways Experiment S t a t i o n A t t e n t i o n WESER-C Pos t O f f i c e Box 631 V icksburg MS 39180

CONVERSION TABLE

M e t r i c t o US Customary

Mu1 t i p l y

m i l l i m e t e r s (mm) cen t imete rs (cm) meters (m) meters (m) k i l omete rs (km) k i 1 ometers ( km)

square meters (m2) 1076 square k i lomete rs (km2) 03861 hectares (ha) 2471

l i t e r s (1) cub ic meters (m3) cub ic meters (m3)

m i 11 igrams (mg) grams (g) k i 1 ograms (kg) m e t r i c tons (t) m e t r i c tons (t)

k i l o c a l o r i e s ( k c a l ) Ce ls ius degrees ( O C )

US Customary t o M e t r i c

inches 2540 inches 254 f e e t ( f t ) 03048 fathoms 1829 s t a t u t e m i l e s ( m i ) 1609 n a u t i c a l m i l e s (nmi) 1852

square f e e t ( f t2) square m i l e s ( m i 2 ) acres

g a l l o n s ( g a l ) cub ic f e e t ( f t 3 ) a c r e - f e e t

ounces (oz) ounces (oz) pounds ( l b ) pounds ( l b ) s h o r t tons ( ton )

B r i t i s h thermal u n i t s (Btu) Fahrenhei t degrees (OF)

To Obta in

inches inches f e e t fathoms s t a t u t e m i l e s n a u t i c a l m i l e s

square f e e t square m i l e s acres

g a l l o n s cub ic f e e t acre- f e e t

ounces ounces pounds pounds s h o r t tons

B r i t i s h thermal u n i t s Fahrenhei t degrees

m i l l i m e t e r s cen t imete rs meters meters k i l omete rs k i 1 ometers

square meters square k i lometers hectares

1 i t e r s cub ic meters cub ic meters

m i l l i g r a m s grams k i lograms m e t r i c tons m e t r i c tons

k i l o c a l o r i e s Ce ls ius degrees

Page

PREFACE ii i CONVERSION FACTORS i v ACKNOWLEDGMENTS v i

NOMENCLATURETAXONOMYRANGE 1 Sum~nerF lounder 1

W i n t e r F l o u n d e r 2 MORPHOLOGYIDENTIFICATON AIDS 2

Summer F lounder 2 a i n t e r F l o u n d e r 2

REASONFORINCLUSIONINSERIES 2 LIFE HISTORY 4

R e p r o d u c t i v e P h y s i o l o g y l S t r a t e g y 4 Spawning 4

Eggs 5 La rvae 5 J u v e n i l e s 6 A d u l t s 6

GROWTH CHARACTERISTICS 9 Growth Rates and Length-Weight R e l a t i o n s h i p s 9

THE FISHERY 1 0 Commercial F i s h e r i e s 1 0 R e c r e a t i o n a l F i s h e r i e s 10 Popul a t i o n Dynamics 10

ECOLOGICALROLE 11 Food H a b i t s 11 Feeding g e h a v i o r 11 P a r a s i t e s 11

ENVIRONMENTAL REQUIREMENTS 1 2 Temperature and Sal i n i t y 1 2 P o l l u t i o n 12

LITERATURE CITED 1 5

ACKNOWL EDmENTS

We would l i k e t o express our s i n c e r e thanks t o Dorothy Wright f o r t y p i n g t h i s manuscr ip t Also we would l i k e t o thank D r L a r r y Ray Grimes f o r t e c h n i c a l ass i s t ance and adv ice We a l so thank John Musick o f t h e V i r g i n i a I n s t i t u t e o f Mar ine Science and Paul S c a r l e t t o f t h e New Jersey D i v i s i o n o f F i s h and Game f o r r e v i e w i n g t h e r e p o r t

Figure 1 A Summer f lounder (Powell 1974) B Winter f lounder ( M a r t i n and Drewry 1978)

SUMMER AND WINTER FLOUNDER

Summer F l ounder

S c i e n t i f i c name P a r a l i c h t h y s d e n t a t u s

P r e f e r r e d common name Summer f l o u n a e r ( F i g u r e 1 A )

Othe r common names F lounder f l u k e p l a i c e f i s h p l a i c e p l a i s e s p l a i c e c h i c k e n ha1 i b u t f l o u n d e r o f New York common f 1 ounder b r a i l

t u r b o t f l a t f i s h l o n g t o o t h e d f l o u n - d e r

C lass Os te i ch thyes Order P leu ronec t i f o rmes Fami ly Both idae Geographic range The summer f l o u n d e r

p r e f 5 r s e s t u a r i n e and s h e l f wa te rs o f t h e A t l a n t i c Ocean I t i s found b e t w e e n N o v a S c o t i d a n d t h e s o u t h e a s t e r n c o a s t o f F l o r i d a b u t i s m o s t a b u n d a n t f r o m C a p e Cod M a s s a c h u s e t t s t o Cape H a t t e r a s N o r t h Caro l i na ( t i i 1 debrand and Schroeder 1928) D i s t r i b u t i o n i n

t h e m i d - A t l a n t i c r eg ion i s shown i n F igu re 2

W in te r F lounder

j c i e n t i f i c name P s e u d o ~ l e u r o n e c t e s ameriranus

P r e t e r r e d common name h i n t e r f 1 ounder ( F i g u r e 1 6 )

Other common names F l a t f i s h S l a c k b a c k Georges Bank f l o u n d e r 1 emon s o l e f l ounaer so le rough f 1 o u n u e r p l i e r o u g e c a r r e l e t ha1 i but ho l i but dab

C lass O s t e i c h t h y e s Order P l e u r o n e c t i f o r m e s F a m i l y P l e u r o n e c t i d a e Geographic range The w i n t e r f l o u n d e r

h a s a b road range o c c u r r i n g f rom B u t t l e Harbor and Windy T i c k l e Labrador t o Beaufor t No r th Caro l ina b u t i s most common i n es tua r i es between t h e G u l f o f S t Lawrence and Chesapeake Bay D i s t r i b u t i o n i n t h e M i d - A t l a n t i c Region i s shown i n F igu re 2

M O R P H O L O G Y I D E N T ~ F I C A T I O N AIDS

Summer F lounder

The boay 3 f t h e summer f l o l ~ n d e r i s l a t e r a l l y f l a t t e n e a a m a r g i i ~ o f t h e p r e o p e r c l e i s f r e e and t h e eyes a r e on t h e l e f t s i d e The bases c f b o t h p e l v i c f i n s a r e s h o r t The o c u l a r s i d e o f t h e f i s h ranges f rom t a n t o d a r k brown and has riunierous o c e l l a t e d spo ts F i v e p rominen t s p o t s are ar ranged i n two t r i a n g l e s w i t h a common apex on t h e l a t e r a l 1ine h o w e v e r t h i s c o n f i g u r a t i o n i s genera l 1 y 1 ack ing i n 1 a r g e r specimens The f i s h a r e a b l e t o b l e n d i n t o t h e i r background b y adap t ing t o t h e t e x t u r e and c o l o r o f t h e s u b s t r a t e on which t h e y l i v e

M e r i s t i c c h a r a c t e r i s t i c s Dorsal rays 80-98 anal rays 63-78 pec to ra l rays 10-13 ver tebrae 40-43 (Smith and Da iber 1977) g i l l r a k e r s on lower l i m b o f f i r s t arch 14-19 Average head l e n g t h and average upper

jaw l e n g t h a re conta ined 396 and 205 t imes r e s p e c t i v e l y i n s tandard 1 ength (SL) (Hi ldebrand and Schroeder 1928) The sca les a re c teno id Late p o s t l arvae o f summer f l ounde r have a we1 1 -de f ined band o f b l a c k pigment a long t h e a n t e r i o r t w o - t h i r d s o f t h e anal f i n and a s i m i l a r band along t h e a n t e r i o r f o u r - f i f t h s o f t h e dorsa l f i n (F igu re 3d) which a re l a c k i n g i n t he southern f l ounde r (Para1 i ch thvs le thos t iqma) and t h e g u l f f l ounde r (P a1 b i q u t t a ) Summer f l ounde r p o s t l arvae t y p i c a l l y have 40-42 t o t a l ver tebrae whi 1 e southern f l ounde r pos t l a r vae have 37 o r 38 and g u l f f l ounde r pos t l a r vae have 36-38 Summer f l ounde r p o s t l arvae have 81 -94 dorsa l r ays and 61-74 anal rays w h i l e gu l f f l ounde r p o s t l arvae have 72-82 dorsa l r ays and 53-63 anal r ays (Deubl e r 1958) Winter Flounder

The w i n t e r f l ounde r s body i s ovate and l a t e r a l l y compressed The eyes a re on t h e r i g h t side separated by a narrow scaled r i dge t he upper eye i s near t h e edge o f t h e head The mouth i s o f moderate s i z e and t h e l e n g t h o f t h e m a x i l l a r y on t h e b l i n d s i d e i s l e s s than o n e - t h i r d t h a t o f t h e head Winter f l ounde r a re 01 i v e green t o reddish-brown i n c o l o r and sometimes have a few r u s t y spots The l a t e r a l 1 i n e i s n e a r l y s t r a i g h t The dorsa l f i n o r i g i n a t e s oppos i te t h e forward edge o f t h e eye and i s o f n e a r l y equal h e i g h t throughout i t s 1 ength

Mer i s t i c c h a r a c t e r i s t i c s Dorsal r ays 56-81 anal r a y s 47-54 pec to ra l r ays 10-11 g i l l r a k e r s on lower l i m b o f f i r s t arch 7-8 ver tebrae 36 Average head l e n g t h i s 40 cm (Hi ldebrand and Schroeder 1928 P ie r ce and Howe 1977) The scales a re c teno id

REASON FOR INCLUSION I N SERIES

The summer f l ounde r i s an impor tan t commerci a1 and r e c r e a t i o n a l

NEW YORK

PHILADELPHIA

ATLANTIC OCEAN

M I L E S

K I L O M E T E R S

Summer flounder

Figure 2 D i s t r i b u t i o n o f t h e Summer and Winter f lounder i n t h e mid-At lant ic reg ion

3

species along the A t l a n t i c seaboard o f the Uni ted States and i s the major r e c r e a t i o n a l l y caught f lounder o f the mid-At1 a n t i c inshore waters There are th ree major commercial f i s h e r i e s the inshore summer f i she ry the o f f sho re w i n t e r f i she ry and a f a l l and w i n t e r t raw l f i she ry i n s i d e the 20-fathom (36-m) contour t h a t developed on the V i r g i n i a and North Carol ina coast i n the 1960s (Hi 1 debrand and Schroeder 1928 Scar1 e t t 1981)

weight f o r w i n t e r f lounder was as f o l l ows I

where W i s weight i n grams

South A t l a n t i c B igh t (Smith 1973) Adu l t summer f lounder move back inshore t o es tua r ies o r coastal waters i n the w i n t e r and spr ing (Wi lk e t a l 1980)

LIFE HISTORY SD awn i ng --

R e p r o d u c t i v e P h y s i o l o g y S t r a t e g y

A d u l t female summer f l o u n d e r on t h e a v e r a g e a r e 6 0 mm l o n g e r ( i n t o t a l length TL) than males a t f i r s t at ta inment o f sexual m a t u r i t y i n the Mid-At1 a n t i c B igh t (Morse 1981) The summer f lounder appears t o become sexua l ly mature by the age o f I 1 (Morse 1981) Gonads o f summer f lounder r ipened from mid-August through November i n the Delaware Bay the f i s h moved o f f sho re t o spawn i n the w i n t e r (Smith and Daiber 1977) Morse (1981) repor ted t h a t summer f lounder have a p ro t rac ted spawning season o f v a r i a b l e du ra t i on w i t h e a r l y maturat ion h igh fecundi ty s e r i a l spawning and ex tens ive migra t ions across the con t inen ta l she l f L i f e h i s t o r y parameters are determined by l o c a l genet ic and environmental fac tors

The number o f maturing ova i n summer f lounder i s h i g h l y co r re la ted w i t h weight and length F ish i n the Mid-At1 a n t i c Region between 366 and 680 mm TL have an est imated 046 t o 419 m i l l i o n ova (Morse 1981)

Total egg count o f w in te r f lounder ranged from 0435 m i 11 i o n f o r an age-I11 f i s h t o 3329 m i l l i o n eggs f o r an age-V f i s h captured o f f Massachusetts (Topp 1968) The reg ress ion equat ion f o r t he r e l a t i o n s h i p o f f ecund i t y t o f i s h

I n t h e S o u t h A t l a n t i c B i g h t spawning t i m e s and h a b i t a t s o f summer f 1 ounder a r e p o o r l y documented Based o n c o l l e c t i o n s o f n e w l y h a t c h e d l a r v a e commerc ia l c a t c h r a t e s and genera l i z e d c o a s t a l and she1 f t r a w l i n g s u r v e y s seasonal m i g r a t i o n p a t t e r n s o f a d u l t f i s h have been deduced I t i s known t h a t summer f l o u n d e r m i g r a t e o f f s h o r e d u r i n g c o o l e r months I n l a t e f a l l w i n t e r o r e a r l y s p r i n g t h e y spawn near t h e bo t tom o f s h e l f wa te rs 30-200 m deep The g e n e t i c a l l y d i s t i n c t p o p u l a t i o n s n o r t h and sou th o f C a p e H a t t e r a s m a y b e h a v e d i f f e r e n t l y

Between Cape Cod P~assachuset ts and Cape L o o k o u t N o r t h C a r o l i n a spawning o f summer f l o u n d e r began i n September (Smi th 1973) I n t h e s u r v e y b y S m i t h ( 1 9 7 3 ) spawning c o n t i n u e d t h r o u g h December i n t h e n o r t h e r n p a r t and t h r o u g h F e b r u a r y t o t h e south Spawn ing i n t h e Mid-At1 a n t i c Region c o n t i n u e s i n t o Februa ry and March i n some y e a r s and p r o b a b l y b e g i n s n o r t h o f C h e s a p e a k e Bay and p r o g r e s s e s southward i n a c y c l e t h a t ends i n t h e South A t l a n t i c B i g h t ( S m i t h 1973) A d u l t summer f 1 o u n d e r move b a c k i n s h o r e t o e s t u a r i e s o r c o a s t a l wa te rs i n t h e w i n t e r and s p r i n g ( W i l k e t a l 1 9 8 0 )

Spawning t imes o f the w i n t e r f lounder are var iab le l i k e those o f the summer f lounder spawning occurs f i r s t i n the southern p a r t o f the

range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

LITERATNE CITED

B i g e l ow HB and W C Schroeder 1953 F i s h e s o f t h e G u l f o f Vlaine US F i s h k i l d l Serv F i s h B u l l 53 577 pp

Breder CM J r 1922 D e s c r i p t i o n o f t h e s p a w n i n g h a b i t s o f P s e u d o p l e u r o n e c t e s a m e r i c a n u s i n c a p t i v i t y Copeia 1023-4

B r e d e r C M J r 1 9 2 4 Some embryonic and l a r v a l s tages o f t h e w i n t e r f l o u n d e r B u l l US Bur F i s h 38311-315

B r i g g s P T 1 3 6 5 T h e s o o r t f i s h e r i e s f c r w i n t e r f l o u n d e r i n s e v e r a l bays o f Long I s l a n d N Y F i s h Game J 1248-70

Burton MP and D R I d l e r 1984 The reproductive cycle i n winter f lounder ~l euronectes - Can J Zool 622563-2567

C a s t e r 1 i n FIE and W W Reyno lds 1982 Thermoregul a t o r y b e h a v i o r and d i e 1 a c t i v i t y o f y e a r l i n g w i n t e r f l o u n d e r ~ s e u d ~ ~ l e u r o n e c t e s americanus Env i ron B i o l F ishes 7177-180

D e a c u t i s CF 1978 E f f e c t o f thermal shock on p r e d a t o r avo idance b y l a r v a e o f two f i s h s p e c i e s Trans Am F i s h Soc 107632-635

D i c k i e LM and FD McCracken 1955 I s o p l e t h d iagrams t o p r e d i c t e q u i l i b r i u m y i e l d s o f a s m a l l f l o u n d e r f i s h e r y J F i s h Res Board Can 12 187-209

Deubler EE J r 1958 A comparative study o f the post larvae o f three flounders (Para1 ichthvs) i n North Carol ina Copeia 1958 112- 116

E d w a r d s R L 1 9 6 8 F i s h e r y r e s o u r c e s o f t h e N o r t h A t l a n t i c area Pages 52-60 i n D G i l b e r t ed The f u t u r e o f t h e f i s h i n g i n d u s t r y o f U n i t e d S t a t e s Un iv Wash Pub l F i s h New Ser 4

Fletcher G L J W Kiceni uk and V P Will iams 1981 E f fec ts o f o i l e d sediments on mor ta l i t y feeding and growth o f w i n t e r f l o u n d e r (Pseudo~ l euronectes americanus) Mar Ecol Prog Ser 491-96

H i 1 debrand S F and WC Schroeder 1928 F i s h e s o f t h e Chesapeake Bay US B u r e a u o f F i s h e r i e s 1024366 PP

H o f f JG and JR Westman 1966 The tempera tu re t o l e r a n c e s o f t h r e e spec ies o f m a r i n e f i s h e s J Mar Res 24131-140

Hoss DE LC C o s t o n and WE Schaaf 1974 E f f e c t s o f seawater e x t r a c t s o f s e d i m e n t s f r o m C h a r l e s t o n Harbor SC on l a r v a l e s t u a r i n e f i s h e s E s t u a r i n e Coas ta l Fiar S c i 2 323-328

Howe AB and PG Coates 1975 W i n t e r f l o u n d e r movements growth and m o r t a l i t y o f f P l a s s a c h u s e t t s Trans Am F i s h Soc 10413-29

Howe AB PG C o a t e s and DE P i e r c e 1976 W i n t e r f l o u n d e r

e s t u a r i n e y e a r - c l ass abundance m o r t a l i t y and r e c r u i t m e n t Trans Am F i s h Soc 105647-657

I t z k o w i t z N and JR S c h u b e l 1983 To1 e r a n c e o f f i v e - d a y - o l d w i n t e r f l o u n d e r pseudopl eu ronec tes americanus 1 arvae t o thermal shock US N a t l Mar F i s h Serv F i s h B u l l 81913-916

I t z k o w i t z N JR S c h u b e l and PMJ Woodhead 1983 R e s ~ o n s e s o f summer f l o u n d e r P a r a l i k h t h y s den ta tus embryos t o thermal shock Env i ron B i o l F i s h e s 8125-135

J e f f r i e s HP and W C Johnson 1974 S e a s o n a l d i s t r i b u t i o n s o f b o t t o m f i s h e s i n t h e N a r r a g a n s e t t 3ay area seven-year v a r i a t i o n s n t h e a ~ u n d a n c e o f w i n t e r f l o u n d e r (Pseudopl eu ronec tes americanus) J F i s h Res 3oard Can 311057- i066

J o h n s I WH H o w e l l and S K l e i n - F a c P h e e 1 9 8 1 Y o l k u t i l i z a t i o n and g rowth t o y o l k sac a b s o r p t i o n i n summer f l o u n d e r ( P a r a l i c h t h y s d e n t a t u s ) l a r v a e a t c o n s t a n t and c y c l i c tempera tu res K a r B i o l ( B e r l ) 63301-330

Kennedy VS and 3H S t e e l e 1971 T h e w i n t e r f l o u n d e r ( P s e u d o p l eu ronec tes americanus) i n L o n g P o n d C o n c e p t i o n B a y Wewfoundl and J F i s h Res Board Can 281153-1165

Keup L and J aay less 1964 F i s h d i s t r i b u t i o n a t v a r y i n g s a l i n i t i e s i n N e u s e R i v e r b a s i n N o r t h Caro l i n a Chesapeake S c i 5119- 123

L a u r e n c e G C 1975 L a b o r a t o r y g r o w t h and me tabo l i sm o f t h e w i n t e r f 1 o u n d e r P s e u d o p l e u r o n e c t e s a m e r i c a n u s f r o m h a t c h i n g t h r o u g h metamorphosis a t t h r e e tempera tu res Mar B i o l ( B e r l ) 32223-229

Lev ings CD 1974 Seasonal changes i n f e e d i n g and p a r t i c l e s e l e c t i o n b y

w i n t e r f l o u n d e r (Pseudopl eu ronec tes amer icanus) Trans Am F i s h Soc 103828-832

M a r t i n FD and GE Drewry 1978 Deve lopment of f i s h e s o f t h e Mid- A t l a n t i c B i g h t an a t l a s o f egg 1 a r v a l and juven i 1 e s tages Vol V I S t r o m a t e i d a e t h r o u g h Ogocepha l i d a e US F i s h W i l d l Serv B i o l Serv Program FWSOBS- 7812 416 pp

McCracken FD 1963 Seasonal movements o f the w in te r f lounder P s e u d o ~ l e u r o n e c t e s americanus (Walbaum) on the A t l a n t i c coast J Fish Res Board Can 20551-586

Morse W W 1981 Reproduc t i on o f t h e summer f l o u n d e r P a r a l i c h t h s d e n t a t u s ( L J d 19189-203

r i a t i o n a l Y a r i n e F i s h e r i e s S e r v i c e 1980 F i s h e r y S t a t i s t i c s o f t h e U n i t e d S t a t e s 1979 US N a t l Far F i s h Serv Cur r F i s h S t a t NO aooo

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987a F i s h e r i e s o f t h e U n i t e d S ta tes 1486 08 N a t l Mar F i s h Serv Cur r F i s h S t a t 8385

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987b Mar ine r e c r e a t i o n a l f i s h e r y s t a t i s t i c s survey A t l a n t i c and g u l f coas ts 1986 US N a t l Mar F i s h Serv Cur r F i s h S t a t 8392

O l l a BL R Wicklund and S Wilk 1969 Behavior o f winter f lounder i n a natura l h a b i t a t Trans Am Fish Soc 98717-720

O l l a BL CE Samet and AL Studholme 1972 A c t i v i t y and feeding behavior o f the summer flounder (Paral i c h t h v ~ dentatus) under c o n t r o l 1 ed 1 abora to ry conditions Fish B u l l 701127- 1136

P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

CONVERSION TABLE

M e t r i c t o US Customary

Mu1 t i p l y

m i l l i m e t e r s (mm) cen t imete rs (cm) meters (m) meters (m) k i l omete rs (km) k i 1 ometers ( km)

square meters (m2) 1076 square k i lomete rs (km2) 03861 hectares (ha) 2471

l i t e r s (1) cub ic meters (m3) cub ic meters (m3)

m i 11 igrams (mg) grams (g) k i 1 ograms (kg) m e t r i c tons (t) m e t r i c tons (t)

k i l o c a l o r i e s ( k c a l ) Ce ls ius degrees ( O C )

US Customary t o M e t r i c

inches 2540 inches 254 f e e t ( f t ) 03048 fathoms 1829 s t a t u t e m i l e s ( m i ) 1609 n a u t i c a l m i l e s (nmi) 1852

square f e e t ( f t2) square m i l e s ( m i 2 ) acres

g a l l o n s ( g a l ) cub ic f e e t ( f t 3 ) a c r e - f e e t

ounces (oz) ounces (oz) pounds ( l b ) pounds ( l b ) s h o r t tons ( ton )

B r i t i s h thermal u n i t s (Btu) Fahrenhei t degrees (OF)

To Obta in

inches inches f e e t fathoms s t a t u t e m i l e s n a u t i c a l m i l e s

square f e e t square m i l e s acres

g a l l o n s cub ic f e e t acre- f e e t

ounces ounces pounds pounds s h o r t tons

B r i t i s h thermal u n i t s Fahrenhei t degrees

m i l l i m e t e r s cen t imete rs meters meters k i l omete rs k i 1 ometers

square meters square k i lometers hectares

1 i t e r s cub ic meters cub ic meters

m i l l i g r a m s grams k i lograms m e t r i c tons m e t r i c tons

k i l o c a l o r i e s Ce ls ius degrees

Page

PREFACE ii i CONVERSION FACTORS i v ACKNOWLEDGMENTS v i

NOMENCLATURETAXONOMYRANGE 1 Sum~nerF lounder 1

W i n t e r F l o u n d e r 2 MORPHOLOGYIDENTIFICATON AIDS 2

Summer F lounder 2 a i n t e r F l o u n d e r 2

REASONFORINCLUSIONINSERIES 2 LIFE HISTORY 4

R e p r o d u c t i v e P h y s i o l o g y l S t r a t e g y 4 Spawning 4

Eggs 5 La rvae 5 J u v e n i l e s 6 A d u l t s 6

GROWTH CHARACTERISTICS 9 Growth Rates and Length-Weight R e l a t i o n s h i p s 9

THE FISHERY 1 0 Commercial F i s h e r i e s 1 0 R e c r e a t i o n a l F i s h e r i e s 10 Popul a t i o n Dynamics 10

ECOLOGICALROLE 11 Food H a b i t s 11 Feeding g e h a v i o r 11 P a r a s i t e s 11

ENVIRONMENTAL REQUIREMENTS 1 2 Temperature and Sal i n i t y 1 2 P o l l u t i o n 12

LITERATURE CITED 1 5

ACKNOWL EDmENTS

We would l i k e t o express our s i n c e r e thanks t o Dorothy Wright f o r t y p i n g t h i s manuscr ip t Also we would l i k e t o thank D r L a r r y Ray Grimes f o r t e c h n i c a l ass i s t ance and adv ice We a l so thank John Musick o f t h e V i r g i n i a I n s t i t u t e o f Mar ine Science and Paul S c a r l e t t o f t h e New Jersey D i v i s i o n o f F i s h and Game f o r r e v i e w i n g t h e r e p o r t

Figure 1 A Summer f lounder (Powell 1974) B Winter f lounder ( M a r t i n and Drewry 1978)

SUMMER AND WINTER FLOUNDER

Summer F l ounder

S c i e n t i f i c name P a r a l i c h t h y s d e n t a t u s

P r e f e r r e d common name Summer f l o u n a e r ( F i g u r e 1 A )

Othe r common names F lounder f l u k e p l a i c e f i s h p l a i c e p l a i s e s p l a i c e c h i c k e n ha1 i b u t f l o u n d e r o f New York common f 1 ounder b r a i l

t u r b o t f l a t f i s h l o n g t o o t h e d f l o u n - d e r

C lass Os te i ch thyes Order P leu ronec t i f o rmes Fami ly Both idae Geographic range The summer f l o u n d e r

p r e f 5 r s e s t u a r i n e and s h e l f wa te rs o f t h e A t l a n t i c Ocean I t i s found b e t w e e n N o v a S c o t i d a n d t h e s o u t h e a s t e r n c o a s t o f F l o r i d a b u t i s m o s t a b u n d a n t f r o m C a p e Cod M a s s a c h u s e t t s t o Cape H a t t e r a s N o r t h Caro l i na ( t i i 1 debrand and Schroeder 1928) D i s t r i b u t i o n i n

t h e m i d - A t l a n t i c r eg ion i s shown i n F igu re 2

W in te r F lounder

j c i e n t i f i c name P s e u d o ~ l e u r o n e c t e s ameriranus

P r e t e r r e d common name h i n t e r f 1 ounder ( F i g u r e 1 6 )

Other common names F l a t f i s h S l a c k b a c k Georges Bank f l o u n d e r 1 emon s o l e f l ounaer so le rough f 1 o u n u e r p l i e r o u g e c a r r e l e t ha1 i but ho l i but dab

C lass O s t e i c h t h y e s Order P l e u r o n e c t i f o r m e s F a m i l y P l e u r o n e c t i d a e Geographic range The w i n t e r f l o u n d e r

h a s a b road range o c c u r r i n g f rom B u t t l e Harbor and Windy T i c k l e Labrador t o Beaufor t No r th Caro l ina b u t i s most common i n es tua r i es between t h e G u l f o f S t Lawrence and Chesapeake Bay D i s t r i b u t i o n i n t h e M i d - A t l a n t i c Region i s shown i n F igu re 2

M O R P H O L O G Y I D E N T ~ F I C A T I O N AIDS

Summer F lounder

The boay 3 f t h e summer f l o l ~ n d e r i s l a t e r a l l y f l a t t e n e a a m a r g i i ~ o f t h e p r e o p e r c l e i s f r e e and t h e eyes a r e on t h e l e f t s i d e The bases c f b o t h p e l v i c f i n s a r e s h o r t The o c u l a r s i d e o f t h e f i s h ranges f rom t a n t o d a r k brown and has riunierous o c e l l a t e d spo ts F i v e p rominen t s p o t s are ar ranged i n two t r i a n g l e s w i t h a common apex on t h e l a t e r a l 1ine h o w e v e r t h i s c o n f i g u r a t i o n i s genera l 1 y 1 ack ing i n 1 a r g e r specimens The f i s h a r e a b l e t o b l e n d i n t o t h e i r background b y adap t ing t o t h e t e x t u r e and c o l o r o f t h e s u b s t r a t e on which t h e y l i v e

M e r i s t i c c h a r a c t e r i s t i c s Dorsal rays 80-98 anal rays 63-78 pec to ra l rays 10-13 ver tebrae 40-43 (Smith and Da iber 1977) g i l l r a k e r s on lower l i m b o f f i r s t arch 14-19 Average head l e n g t h and average upper

jaw l e n g t h a re conta ined 396 and 205 t imes r e s p e c t i v e l y i n s tandard 1 ength (SL) (Hi ldebrand and Schroeder 1928) The sca les a re c teno id Late p o s t l arvae o f summer f l ounde r have a we1 1 -de f ined band o f b l a c k pigment a long t h e a n t e r i o r t w o - t h i r d s o f t h e anal f i n and a s i m i l a r band along t h e a n t e r i o r f o u r - f i f t h s o f t h e dorsa l f i n (F igu re 3d) which a re l a c k i n g i n t he southern f l ounde r (Para1 i ch thvs le thos t iqma) and t h e g u l f f l ounde r (P a1 b i q u t t a ) Summer f l ounde r p o s t l arvae t y p i c a l l y have 40-42 t o t a l ver tebrae whi 1 e southern f l ounde r pos t l a r vae have 37 o r 38 and g u l f f l ounde r pos t l a r vae have 36-38 Summer f l ounde r p o s t l arvae have 81 -94 dorsa l r ays and 61-74 anal rays w h i l e gu l f f l ounde r p o s t l arvae have 72-82 dorsa l r ays and 53-63 anal r ays (Deubl e r 1958) Winter Flounder

The w i n t e r f l ounde r s body i s ovate and l a t e r a l l y compressed The eyes a re on t h e r i g h t side separated by a narrow scaled r i dge t he upper eye i s near t h e edge o f t h e head The mouth i s o f moderate s i z e and t h e l e n g t h o f t h e m a x i l l a r y on t h e b l i n d s i d e i s l e s s than o n e - t h i r d t h a t o f t h e head Winter f l ounde r a re 01 i v e green t o reddish-brown i n c o l o r and sometimes have a few r u s t y spots The l a t e r a l 1 i n e i s n e a r l y s t r a i g h t The dorsa l f i n o r i g i n a t e s oppos i te t h e forward edge o f t h e eye and i s o f n e a r l y equal h e i g h t throughout i t s 1 ength

Mer i s t i c c h a r a c t e r i s t i c s Dorsal r ays 56-81 anal r a y s 47-54 pec to ra l r ays 10-11 g i l l r a k e r s on lower l i m b o f f i r s t arch 7-8 ver tebrae 36 Average head l e n g t h i s 40 cm (Hi ldebrand and Schroeder 1928 P ie r ce and Howe 1977) The scales a re c teno id

REASON FOR INCLUSION I N SERIES

The summer f l ounde r i s an impor tan t commerci a1 and r e c r e a t i o n a l

NEW YORK

PHILADELPHIA

ATLANTIC OCEAN

M I L E S

K I L O M E T E R S

Summer flounder

Figure 2 D i s t r i b u t i o n o f t h e Summer and Winter f lounder i n t h e mid-At lant ic reg ion

3

species along the A t l a n t i c seaboard o f the Uni ted States and i s the major r e c r e a t i o n a l l y caught f lounder o f the mid-At1 a n t i c inshore waters There are th ree major commercial f i s h e r i e s the inshore summer f i she ry the o f f sho re w i n t e r f i she ry and a f a l l and w i n t e r t raw l f i she ry i n s i d e the 20-fathom (36-m) contour t h a t developed on the V i r g i n i a and North Carol ina coast i n the 1960s (Hi 1 debrand and Schroeder 1928 Scar1 e t t 1981)

weight f o r w i n t e r f lounder was as f o l l ows I

where W i s weight i n grams

South A t l a n t i c B igh t (Smith 1973) Adu l t summer f lounder move back inshore t o es tua r ies o r coastal waters i n the w i n t e r and spr ing (Wi lk e t a l 1980)

LIFE HISTORY SD awn i ng --

R e p r o d u c t i v e P h y s i o l o g y S t r a t e g y

A d u l t female summer f l o u n d e r on t h e a v e r a g e a r e 6 0 mm l o n g e r ( i n t o t a l length TL) than males a t f i r s t at ta inment o f sexual m a t u r i t y i n the Mid-At1 a n t i c B igh t (Morse 1981) The summer f lounder appears t o become sexua l ly mature by the age o f I 1 (Morse 1981) Gonads o f summer f lounder r ipened from mid-August through November i n the Delaware Bay the f i s h moved o f f sho re t o spawn i n the w i n t e r (Smith and Daiber 1977) Morse (1981) repor ted t h a t summer f lounder have a p ro t rac ted spawning season o f v a r i a b l e du ra t i on w i t h e a r l y maturat ion h igh fecundi ty s e r i a l spawning and ex tens ive migra t ions across the con t inen ta l she l f L i f e h i s t o r y parameters are determined by l o c a l genet ic and environmental fac tors

The number o f maturing ova i n summer f lounder i s h i g h l y co r re la ted w i t h weight and length F ish i n the Mid-At1 a n t i c Region between 366 and 680 mm TL have an est imated 046 t o 419 m i l l i o n ova (Morse 1981)

Total egg count o f w in te r f lounder ranged from 0435 m i 11 i o n f o r an age-I11 f i s h t o 3329 m i l l i o n eggs f o r an age-V f i s h captured o f f Massachusetts (Topp 1968) The reg ress ion equat ion f o r t he r e l a t i o n s h i p o f f ecund i t y t o f i s h

I n t h e S o u t h A t l a n t i c B i g h t spawning t i m e s and h a b i t a t s o f summer f 1 ounder a r e p o o r l y documented Based o n c o l l e c t i o n s o f n e w l y h a t c h e d l a r v a e commerc ia l c a t c h r a t e s and genera l i z e d c o a s t a l and she1 f t r a w l i n g s u r v e y s seasonal m i g r a t i o n p a t t e r n s o f a d u l t f i s h have been deduced I t i s known t h a t summer f l o u n d e r m i g r a t e o f f s h o r e d u r i n g c o o l e r months I n l a t e f a l l w i n t e r o r e a r l y s p r i n g t h e y spawn near t h e bo t tom o f s h e l f wa te rs 30-200 m deep The g e n e t i c a l l y d i s t i n c t p o p u l a t i o n s n o r t h and sou th o f C a p e H a t t e r a s m a y b e h a v e d i f f e r e n t l y

Between Cape Cod P~assachuset ts and Cape L o o k o u t N o r t h C a r o l i n a spawning o f summer f l o u n d e r began i n September (Smi th 1973) I n t h e s u r v e y b y S m i t h ( 1 9 7 3 ) spawning c o n t i n u e d t h r o u g h December i n t h e n o r t h e r n p a r t and t h r o u g h F e b r u a r y t o t h e south Spawn ing i n t h e Mid-At1 a n t i c Region c o n t i n u e s i n t o Februa ry and March i n some y e a r s and p r o b a b l y b e g i n s n o r t h o f C h e s a p e a k e Bay and p r o g r e s s e s southward i n a c y c l e t h a t ends i n t h e South A t l a n t i c B i g h t ( S m i t h 1973) A d u l t summer f 1 o u n d e r move b a c k i n s h o r e t o e s t u a r i e s o r c o a s t a l wa te rs i n t h e w i n t e r and s p r i n g ( W i l k e t a l 1 9 8 0 )

Spawning t imes o f the w i n t e r f lounder are var iab le l i k e those o f the summer f lounder spawning occurs f i r s t i n the southern p a r t o f the

range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

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PREFACE ii i CONVERSION FACTORS i v ACKNOWLEDGMENTS v i

NOMENCLATURETAXONOMYRANGE 1 Sum~nerF lounder 1

W i n t e r F l o u n d e r 2 MORPHOLOGYIDENTIFICATON AIDS 2

Summer F lounder 2 a i n t e r F l o u n d e r 2

REASONFORINCLUSIONINSERIES 2 LIFE HISTORY 4

R e p r o d u c t i v e P h y s i o l o g y l S t r a t e g y 4 Spawning 4

Eggs 5 La rvae 5 J u v e n i l e s 6 A d u l t s 6

GROWTH CHARACTERISTICS 9 Growth Rates and Length-Weight R e l a t i o n s h i p s 9

THE FISHERY 1 0 Commercial F i s h e r i e s 1 0 R e c r e a t i o n a l F i s h e r i e s 10 Popul a t i o n Dynamics 10

ECOLOGICALROLE 11 Food H a b i t s 11 Feeding g e h a v i o r 11 P a r a s i t e s 11

ENVIRONMENTAL REQUIREMENTS 1 2 Temperature and Sal i n i t y 1 2 P o l l u t i o n 12

LITERATURE CITED 1 5

ACKNOWL EDmENTS

We would l i k e t o express our s i n c e r e thanks t o Dorothy Wright f o r t y p i n g t h i s manuscr ip t Also we would l i k e t o thank D r L a r r y Ray Grimes f o r t e c h n i c a l ass i s t ance and adv ice We a l so thank John Musick o f t h e V i r g i n i a I n s t i t u t e o f Mar ine Science and Paul S c a r l e t t o f t h e New Jersey D i v i s i o n o f F i s h and Game f o r r e v i e w i n g t h e r e p o r t

Figure 1 A Summer f lounder (Powell 1974) B Winter f lounder ( M a r t i n and Drewry 1978)

SUMMER AND WINTER FLOUNDER

Summer F l ounder

S c i e n t i f i c name P a r a l i c h t h y s d e n t a t u s

P r e f e r r e d common name Summer f l o u n a e r ( F i g u r e 1 A )

Othe r common names F lounder f l u k e p l a i c e f i s h p l a i c e p l a i s e s p l a i c e c h i c k e n ha1 i b u t f l o u n d e r o f New York common f 1 ounder b r a i l

t u r b o t f l a t f i s h l o n g t o o t h e d f l o u n - d e r

C lass Os te i ch thyes Order P leu ronec t i f o rmes Fami ly Both idae Geographic range The summer f l o u n d e r

p r e f 5 r s e s t u a r i n e and s h e l f wa te rs o f t h e A t l a n t i c Ocean I t i s found b e t w e e n N o v a S c o t i d a n d t h e s o u t h e a s t e r n c o a s t o f F l o r i d a b u t i s m o s t a b u n d a n t f r o m C a p e Cod M a s s a c h u s e t t s t o Cape H a t t e r a s N o r t h Caro l i na ( t i i 1 debrand and Schroeder 1928) D i s t r i b u t i o n i n

t h e m i d - A t l a n t i c r eg ion i s shown i n F igu re 2

W in te r F lounder

j c i e n t i f i c name P s e u d o ~ l e u r o n e c t e s ameriranus

P r e t e r r e d common name h i n t e r f 1 ounder ( F i g u r e 1 6 )

Other common names F l a t f i s h S l a c k b a c k Georges Bank f l o u n d e r 1 emon s o l e f l ounaer so le rough f 1 o u n u e r p l i e r o u g e c a r r e l e t ha1 i but ho l i but dab

C lass O s t e i c h t h y e s Order P l e u r o n e c t i f o r m e s F a m i l y P l e u r o n e c t i d a e Geographic range The w i n t e r f l o u n d e r

h a s a b road range o c c u r r i n g f rom B u t t l e Harbor and Windy T i c k l e Labrador t o Beaufor t No r th Caro l ina b u t i s most common i n es tua r i es between t h e G u l f o f S t Lawrence and Chesapeake Bay D i s t r i b u t i o n i n t h e M i d - A t l a n t i c Region i s shown i n F igu re 2

M O R P H O L O G Y I D E N T ~ F I C A T I O N AIDS

Summer F lounder

The boay 3 f t h e summer f l o l ~ n d e r i s l a t e r a l l y f l a t t e n e a a m a r g i i ~ o f t h e p r e o p e r c l e i s f r e e and t h e eyes a r e on t h e l e f t s i d e The bases c f b o t h p e l v i c f i n s a r e s h o r t The o c u l a r s i d e o f t h e f i s h ranges f rom t a n t o d a r k brown and has riunierous o c e l l a t e d spo ts F i v e p rominen t s p o t s are ar ranged i n two t r i a n g l e s w i t h a common apex on t h e l a t e r a l 1ine h o w e v e r t h i s c o n f i g u r a t i o n i s genera l 1 y 1 ack ing i n 1 a r g e r specimens The f i s h a r e a b l e t o b l e n d i n t o t h e i r background b y adap t ing t o t h e t e x t u r e and c o l o r o f t h e s u b s t r a t e on which t h e y l i v e

M e r i s t i c c h a r a c t e r i s t i c s Dorsal rays 80-98 anal rays 63-78 pec to ra l rays 10-13 ver tebrae 40-43 (Smith and Da iber 1977) g i l l r a k e r s on lower l i m b o f f i r s t arch 14-19 Average head l e n g t h and average upper

jaw l e n g t h a re conta ined 396 and 205 t imes r e s p e c t i v e l y i n s tandard 1 ength (SL) (Hi ldebrand and Schroeder 1928) The sca les a re c teno id Late p o s t l arvae o f summer f l ounde r have a we1 1 -de f ined band o f b l a c k pigment a long t h e a n t e r i o r t w o - t h i r d s o f t h e anal f i n and a s i m i l a r band along t h e a n t e r i o r f o u r - f i f t h s o f t h e dorsa l f i n (F igu re 3d) which a re l a c k i n g i n t he southern f l ounde r (Para1 i ch thvs le thos t iqma) and t h e g u l f f l ounde r (P a1 b i q u t t a ) Summer f l ounde r p o s t l arvae t y p i c a l l y have 40-42 t o t a l ver tebrae whi 1 e southern f l ounde r pos t l a r vae have 37 o r 38 and g u l f f l ounde r pos t l a r vae have 36-38 Summer f l ounde r p o s t l arvae have 81 -94 dorsa l r ays and 61-74 anal rays w h i l e gu l f f l ounde r p o s t l arvae have 72-82 dorsa l r ays and 53-63 anal r ays (Deubl e r 1958) Winter Flounder

The w i n t e r f l ounde r s body i s ovate and l a t e r a l l y compressed The eyes a re on t h e r i g h t side separated by a narrow scaled r i dge t he upper eye i s near t h e edge o f t h e head The mouth i s o f moderate s i z e and t h e l e n g t h o f t h e m a x i l l a r y on t h e b l i n d s i d e i s l e s s than o n e - t h i r d t h a t o f t h e head Winter f l ounde r a re 01 i v e green t o reddish-brown i n c o l o r and sometimes have a few r u s t y spots The l a t e r a l 1 i n e i s n e a r l y s t r a i g h t The dorsa l f i n o r i g i n a t e s oppos i te t h e forward edge o f t h e eye and i s o f n e a r l y equal h e i g h t throughout i t s 1 ength

Mer i s t i c c h a r a c t e r i s t i c s Dorsal r ays 56-81 anal r a y s 47-54 pec to ra l r ays 10-11 g i l l r a k e r s on lower l i m b o f f i r s t arch 7-8 ver tebrae 36 Average head l e n g t h i s 40 cm (Hi ldebrand and Schroeder 1928 P ie r ce and Howe 1977) The scales a re c teno id

REASON FOR INCLUSION I N SERIES

The summer f l ounde r i s an impor tan t commerci a1 and r e c r e a t i o n a l

NEW YORK

PHILADELPHIA

ATLANTIC OCEAN

M I L E S

K I L O M E T E R S

Summer flounder

Figure 2 D i s t r i b u t i o n o f t h e Summer and Winter f lounder i n t h e mid-At lant ic reg ion

3

species along the A t l a n t i c seaboard o f the Uni ted States and i s the major r e c r e a t i o n a l l y caught f lounder o f the mid-At1 a n t i c inshore waters There are th ree major commercial f i s h e r i e s the inshore summer f i she ry the o f f sho re w i n t e r f i she ry and a f a l l and w i n t e r t raw l f i she ry i n s i d e the 20-fathom (36-m) contour t h a t developed on the V i r g i n i a and North Carol ina coast i n the 1960s (Hi 1 debrand and Schroeder 1928 Scar1 e t t 1981)

weight f o r w i n t e r f lounder was as f o l l ows I

where W i s weight i n grams

South A t l a n t i c B igh t (Smith 1973) Adu l t summer f lounder move back inshore t o es tua r ies o r coastal waters i n the w i n t e r and spr ing (Wi lk e t a l 1980)

LIFE HISTORY SD awn i ng --

R e p r o d u c t i v e P h y s i o l o g y S t r a t e g y

A d u l t female summer f l o u n d e r on t h e a v e r a g e a r e 6 0 mm l o n g e r ( i n t o t a l length TL) than males a t f i r s t at ta inment o f sexual m a t u r i t y i n the Mid-At1 a n t i c B igh t (Morse 1981) The summer f lounder appears t o become sexua l ly mature by the age o f I 1 (Morse 1981) Gonads o f summer f lounder r ipened from mid-August through November i n the Delaware Bay the f i s h moved o f f sho re t o spawn i n the w i n t e r (Smith and Daiber 1977) Morse (1981) repor ted t h a t summer f lounder have a p ro t rac ted spawning season o f v a r i a b l e du ra t i on w i t h e a r l y maturat ion h igh fecundi ty s e r i a l spawning and ex tens ive migra t ions across the con t inen ta l she l f L i f e h i s t o r y parameters are determined by l o c a l genet ic and environmental fac tors

The number o f maturing ova i n summer f lounder i s h i g h l y co r re la ted w i t h weight and length F ish i n the Mid-At1 a n t i c Region between 366 and 680 mm TL have an est imated 046 t o 419 m i l l i o n ova (Morse 1981)

Total egg count o f w in te r f lounder ranged from 0435 m i 11 i o n f o r an age-I11 f i s h t o 3329 m i l l i o n eggs f o r an age-V f i s h captured o f f Massachusetts (Topp 1968) The reg ress ion equat ion f o r t he r e l a t i o n s h i p o f f ecund i t y t o f i s h

I n t h e S o u t h A t l a n t i c B i g h t spawning t i m e s and h a b i t a t s o f summer f 1 ounder a r e p o o r l y documented Based o n c o l l e c t i o n s o f n e w l y h a t c h e d l a r v a e commerc ia l c a t c h r a t e s and genera l i z e d c o a s t a l and she1 f t r a w l i n g s u r v e y s seasonal m i g r a t i o n p a t t e r n s o f a d u l t f i s h have been deduced I t i s known t h a t summer f l o u n d e r m i g r a t e o f f s h o r e d u r i n g c o o l e r months I n l a t e f a l l w i n t e r o r e a r l y s p r i n g t h e y spawn near t h e bo t tom o f s h e l f wa te rs 30-200 m deep The g e n e t i c a l l y d i s t i n c t p o p u l a t i o n s n o r t h and sou th o f C a p e H a t t e r a s m a y b e h a v e d i f f e r e n t l y

Between Cape Cod P~assachuset ts and Cape L o o k o u t N o r t h C a r o l i n a spawning o f summer f l o u n d e r began i n September (Smi th 1973) I n t h e s u r v e y b y S m i t h ( 1 9 7 3 ) spawning c o n t i n u e d t h r o u g h December i n t h e n o r t h e r n p a r t and t h r o u g h F e b r u a r y t o t h e south Spawn ing i n t h e Mid-At1 a n t i c Region c o n t i n u e s i n t o Februa ry and March i n some y e a r s and p r o b a b l y b e g i n s n o r t h o f C h e s a p e a k e Bay and p r o g r e s s e s southward i n a c y c l e t h a t ends i n t h e South A t l a n t i c B i g h t ( S m i t h 1973) A d u l t summer f 1 o u n d e r move b a c k i n s h o r e t o e s t u a r i e s o r c o a s t a l wa te rs i n t h e w i n t e r and s p r i n g ( W i l k e t a l 1 9 8 0 )

Spawning t imes o f the w i n t e r f lounder are var iab le l i k e those o f the summer f lounder spawning occurs f i r s t i n the southern p a r t o f the

range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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B r e d e r C M J r 1 9 2 4 Some embryonic and l a r v a l s tages o f t h e w i n t e r f l o u n d e r B u l l US Bur F i s h 38311-315

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Burton MP and D R I d l e r 1984 The reproductive cycle i n winter f lounder ~l euronectes - Can J Zool 622563-2567

C a s t e r 1 i n FIE and W W Reyno lds 1982 Thermoregul a t o r y b e h a v i o r and d i e 1 a c t i v i t y o f y e a r l i n g w i n t e r f l o u n d e r ~ s e u d ~ ~ l e u r o n e c t e s americanus Env i ron B i o l F ishes 7177-180

D e a c u t i s CF 1978 E f f e c t o f thermal shock on p r e d a t o r avo idance b y l a r v a e o f two f i s h s p e c i e s Trans Am F i s h Soc 107632-635

D i c k i e LM and FD McCracken 1955 I s o p l e t h d iagrams t o p r e d i c t e q u i l i b r i u m y i e l d s o f a s m a l l f l o u n d e r f i s h e r y J F i s h Res Board Can 12 187-209

Deubler EE J r 1958 A comparative study o f the post larvae o f three flounders (Para1 ichthvs) i n North Carol ina Copeia 1958 112- 116

E d w a r d s R L 1 9 6 8 F i s h e r y r e s o u r c e s o f t h e N o r t h A t l a n t i c area Pages 52-60 i n D G i l b e r t ed The f u t u r e o f t h e f i s h i n g i n d u s t r y o f U n i t e d S t a t e s Un iv Wash Pub l F i s h New Ser 4

Fletcher G L J W Kiceni uk and V P Will iams 1981 E f fec ts o f o i l e d sediments on mor ta l i t y feeding and growth o f w i n t e r f l o u n d e r (Pseudo~ l euronectes americanus) Mar Ecol Prog Ser 491-96

H i 1 debrand S F and WC Schroeder 1928 F i s h e s o f t h e Chesapeake Bay US B u r e a u o f F i s h e r i e s 1024366 PP

H o f f JG and JR Westman 1966 The tempera tu re t o l e r a n c e s o f t h r e e spec ies o f m a r i n e f i s h e s J Mar Res 24131-140

Hoss DE LC C o s t o n and WE Schaaf 1974 E f f e c t s o f seawater e x t r a c t s o f s e d i m e n t s f r o m C h a r l e s t o n Harbor SC on l a r v a l e s t u a r i n e f i s h e s E s t u a r i n e Coas ta l Fiar S c i 2 323-328

Howe AB and PG Coates 1975 W i n t e r f l o u n d e r movements growth and m o r t a l i t y o f f P l a s s a c h u s e t t s Trans Am F i s h Soc 10413-29

Howe AB PG C o a t e s and DE P i e r c e 1976 W i n t e r f l o u n d e r

e s t u a r i n e y e a r - c l ass abundance m o r t a l i t y and r e c r u i t m e n t Trans Am F i s h Soc 105647-657

I t z k o w i t z N and JR S c h u b e l 1983 To1 e r a n c e o f f i v e - d a y - o l d w i n t e r f l o u n d e r pseudopl eu ronec tes americanus 1 arvae t o thermal shock US N a t l Mar F i s h Serv F i s h B u l l 81913-916

I t z k o w i t z N JR S c h u b e l and PMJ Woodhead 1983 R e s ~ o n s e s o f summer f l o u n d e r P a r a l i k h t h y s den ta tus embryos t o thermal shock Env i ron B i o l F i s h e s 8125-135

J e f f r i e s HP and W C Johnson 1974 S e a s o n a l d i s t r i b u t i o n s o f b o t t o m f i s h e s i n t h e N a r r a g a n s e t t 3ay area seven-year v a r i a t i o n s n t h e a ~ u n d a n c e o f w i n t e r f l o u n d e r (Pseudopl eu ronec tes americanus) J F i s h Res 3oard Can 311057- i066

J o h n s I WH H o w e l l and S K l e i n - F a c P h e e 1 9 8 1 Y o l k u t i l i z a t i o n and g rowth t o y o l k sac a b s o r p t i o n i n summer f l o u n d e r ( P a r a l i c h t h y s d e n t a t u s ) l a r v a e a t c o n s t a n t and c y c l i c tempera tu res K a r B i o l ( B e r l ) 63301-330

Kennedy VS and 3H S t e e l e 1971 T h e w i n t e r f l o u n d e r ( P s e u d o p l eu ronec tes americanus) i n L o n g P o n d C o n c e p t i o n B a y Wewfoundl and J F i s h Res Board Can 281153-1165

Keup L and J aay less 1964 F i s h d i s t r i b u t i o n a t v a r y i n g s a l i n i t i e s i n N e u s e R i v e r b a s i n N o r t h Caro l i n a Chesapeake S c i 5119- 123

L a u r e n c e G C 1975 L a b o r a t o r y g r o w t h and me tabo l i sm o f t h e w i n t e r f 1 o u n d e r P s e u d o p l e u r o n e c t e s a m e r i c a n u s f r o m h a t c h i n g t h r o u g h metamorphosis a t t h r e e tempera tu res Mar B i o l ( B e r l ) 32223-229

Lev ings CD 1974 Seasonal changes i n f e e d i n g and p a r t i c l e s e l e c t i o n b y

w i n t e r f l o u n d e r (Pseudopl eu ronec tes amer icanus) Trans Am F i s h Soc 103828-832

M a r t i n FD and GE Drewry 1978 Deve lopment of f i s h e s o f t h e Mid- A t l a n t i c B i g h t an a t l a s o f egg 1 a r v a l and juven i 1 e s tages Vol V I S t r o m a t e i d a e t h r o u g h Ogocepha l i d a e US F i s h W i l d l Serv B i o l Serv Program FWSOBS- 7812 416 pp

McCracken FD 1963 Seasonal movements o f the w in te r f lounder P s e u d o ~ l e u r o n e c t e s americanus (Walbaum) on the A t l a n t i c coast J Fish Res Board Can 20551-586

Morse W W 1981 Reproduc t i on o f t h e summer f l o u n d e r P a r a l i c h t h s d e n t a t u s ( L J d 19189-203

r i a t i o n a l Y a r i n e F i s h e r i e s S e r v i c e 1980 F i s h e r y S t a t i s t i c s o f t h e U n i t e d S t a t e s 1979 US N a t l Far F i s h Serv Cur r F i s h S t a t NO aooo

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987a F i s h e r i e s o f t h e U n i t e d S ta tes 1486 08 N a t l Mar F i s h Serv Cur r F i s h S t a t 8385

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987b Mar ine r e c r e a t i o n a l f i s h e r y s t a t i s t i c s survey A t l a n t i c and g u l f coas ts 1986 US N a t l Mar F i s h Serv Cur r F i s h S t a t 8392

O l l a BL R Wicklund and S Wilk 1969 Behavior o f winter f lounder i n a natura l h a b i t a t Trans Am Fish Soc 98717-720

O l l a BL CE Samet and AL Studholme 1972 A c t i v i t y and feeding behavior o f the summer flounder (Paral i c h t h v ~ dentatus) under c o n t r o l 1 ed 1 abora to ry conditions Fish B u l l 701127- 1136

P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

ACKNOWL EDmENTS

We would l i k e t o express our s i n c e r e thanks t o Dorothy Wright f o r t y p i n g t h i s manuscr ip t Also we would l i k e t o thank D r L a r r y Ray Grimes f o r t e c h n i c a l ass i s t ance and adv ice We a l so thank John Musick o f t h e V i r g i n i a I n s t i t u t e o f Mar ine Science and Paul S c a r l e t t o f t h e New Jersey D i v i s i o n o f F i s h and Game f o r r e v i e w i n g t h e r e p o r t

Figure 1 A Summer f lounder (Powell 1974) B Winter f lounder ( M a r t i n and Drewry 1978)

SUMMER AND WINTER FLOUNDER

Summer F l ounder

S c i e n t i f i c name P a r a l i c h t h y s d e n t a t u s

P r e f e r r e d common name Summer f l o u n a e r ( F i g u r e 1 A )

Othe r common names F lounder f l u k e p l a i c e f i s h p l a i c e p l a i s e s p l a i c e c h i c k e n ha1 i b u t f l o u n d e r o f New York common f 1 ounder b r a i l

t u r b o t f l a t f i s h l o n g t o o t h e d f l o u n - d e r

C lass Os te i ch thyes Order P leu ronec t i f o rmes Fami ly Both idae Geographic range The summer f l o u n d e r

p r e f 5 r s e s t u a r i n e and s h e l f wa te rs o f t h e A t l a n t i c Ocean I t i s found b e t w e e n N o v a S c o t i d a n d t h e s o u t h e a s t e r n c o a s t o f F l o r i d a b u t i s m o s t a b u n d a n t f r o m C a p e Cod M a s s a c h u s e t t s t o Cape H a t t e r a s N o r t h Caro l i na ( t i i 1 debrand and Schroeder 1928) D i s t r i b u t i o n i n

t h e m i d - A t l a n t i c r eg ion i s shown i n F igu re 2

W in te r F lounder

j c i e n t i f i c name P s e u d o ~ l e u r o n e c t e s ameriranus

P r e t e r r e d common name h i n t e r f 1 ounder ( F i g u r e 1 6 )

Other common names F l a t f i s h S l a c k b a c k Georges Bank f l o u n d e r 1 emon s o l e f l ounaer so le rough f 1 o u n u e r p l i e r o u g e c a r r e l e t ha1 i but ho l i but dab

C lass O s t e i c h t h y e s Order P l e u r o n e c t i f o r m e s F a m i l y P l e u r o n e c t i d a e Geographic range The w i n t e r f l o u n d e r

h a s a b road range o c c u r r i n g f rom B u t t l e Harbor and Windy T i c k l e Labrador t o Beaufor t No r th Caro l ina b u t i s most common i n es tua r i es between t h e G u l f o f S t Lawrence and Chesapeake Bay D i s t r i b u t i o n i n t h e M i d - A t l a n t i c Region i s shown i n F igu re 2

M O R P H O L O G Y I D E N T ~ F I C A T I O N AIDS

Summer F lounder

The boay 3 f t h e summer f l o l ~ n d e r i s l a t e r a l l y f l a t t e n e a a m a r g i i ~ o f t h e p r e o p e r c l e i s f r e e and t h e eyes a r e on t h e l e f t s i d e The bases c f b o t h p e l v i c f i n s a r e s h o r t The o c u l a r s i d e o f t h e f i s h ranges f rom t a n t o d a r k brown and has riunierous o c e l l a t e d spo ts F i v e p rominen t s p o t s are ar ranged i n two t r i a n g l e s w i t h a common apex on t h e l a t e r a l 1ine h o w e v e r t h i s c o n f i g u r a t i o n i s genera l 1 y 1 ack ing i n 1 a r g e r specimens The f i s h a r e a b l e t o b l e n d i n t o t h e i r background b y adap t ing t o t h e t e x t u r e and c o l o r o f t h e s u b s t r a t e on which t h e y l i v e

M e r i s t i c c h a r a c t e r i s t i c s Dorsal rays 80-98 anal rays 63-78 pec to ra l rays 10-13 ver tebrae 40-43 (Smith and Da iber 1977) g i l l r a k e r s on lower l i m b o f f i r s t arch 14-19 Average head l e n g t h and average upper

jaw l e n g t h a re conta ined 396 and 205 t imes r e s p e c t i v e l y i n s tandard 1 ength (SL) (Hi ldebrand and Schroeder 1928) The sca les a re c teno id Late p o s t l arvae o f summer f l ounde r have a we1 1 -de f ined band o f b l a c k pigment a long t h e a n t e r i o r t w o - t h i r d s o f t h e anal f i n and a s i m i l a r band along t h e a n t e r i o r f o u r - f i f t h s o f t h e dorsa l f i n (F igu re 3d) which a re l a c k i n g i n t he southern f l ounde r (Para1 i ch thvs le thos t iqma) and t h e g u l f f l ounde r (P a1 b i q u t t a ) Summer f l ounde r p o s t l arvae t y p i c a l l y have 40-42 t o t a l ver tebrae whi 1 e southern f l ounde r pos t l a r vae have 37 o r 38 and g u l f f l ounde r pos t l a r vae have 36-38 Summer f l ounde r p o s t l arvae have 81 -94 dorsa l r ays and 61-74 anal rays w h i l e gu l f f l ounde r p o s t l arvae have 72-82 dorsa l r ays and 53-63 anal r ays (Deubl e r 1958) Winter Flounder

The w i n t e r f l ounde r s body i s ovate and l a t e r a l l y compressed The eyes a re on t h e r i g h t side separated by a narrow scaled r i dge t he upper eye i s near t h e edge o f t h e head The mouth i s o f moderate s i z e and t h e l e n g t h o f t h e m a x i l l a r y on t h e b l i n d s i d e i s l e s s than o n e - t h i r d t h a t o f t h e head Winter f l ounde r a re 01 i v e green t o reddish-brown i n c o l o r and sometimes have a few r u s t y spots The l a t e r a l 1 i n e i s n e a r l y s t r a i g h t The dorsa l f i n o r i g i n a t e s oppos i te t h e forward edge o f t h e eye and i s o f n e a r l y equal h e i g h t throughout i t s 1 ength

Mer i s t i c c h a r a c t e r i s t i c s Dorsal r ays 56-81 anal r a y s 47-54 pec to ra l r ays 10-11 g i l l r a k e r s on lower l i m b o f f i r s t arch 7-8 ver tebrae 36 Average head l e n g t h i s 40 cm (Hi ldebrand and Schroeder 1928 P ie r ce and Howe 1977) The scales a re c teno id

REASON FOR INCLUSION I N SERIES

The summer f l ounde r i s an impor tan t commerci a1 and r e c r e a t i o n a l

NEW YORK

PHILADELPHIA

ATLANTIC OCEAN

M I L E S

K I L O M E T E R S

Summer flounder

Figure 2 D i s t r i b u t i o n o f t h e Summer and Winter f lounder i n t h e mid-At lant ic reg ion

3

species along the A t l a n t i c seaboard o f the Uni ted States and i s the major r e c r e a t i o n a l l y caught f lounder o f the mid-At1 a n t i c inshore waters There are th ree major commercial f i s h e r i e s the inshore summer f i she ry the o f f sho re w i n t e r f i she ry and a f a l l and w i n t e r t raw l f i she ry i n s i d e the 20-fathom (36-m) contour t h a t developed on the V i r g i n i a and North Carol ina coast i n the 1960s (Hi 1 debrand and Schroeder 1928 Scar1 e t t 1981)

weight f o r w i n t e r f lounder was as f o l l ows I

where W i s weight i n grams

South A t l a n t i c B igh t (Smith 1973) Adu l t summer f lounder move back inshore t o es tua r ies o r coastal waters i n the w i n t e r and spr ing (Wi lk e t a l 1980)

LIFE HISTORY SD awn i ng --

R e p r o d u c t i v e P h y s i o l o g y S t r a t e g y

A d u l t female summer f l o u n d e r on t h e a v e r a g e a r e 6 0 mm l o n g e r ( i n t o t a l length TL) than males a t f i r s t at ta inment o f sexual m a t u r i t y i n the Mid-At1 a n t i c B igh t (Morse 1981) The summer f lounder appears t o become sexua l ly mature by the age o f I 1 (Morse 1981) Gonads o f summer f lounder r ipened from mid-August through November i n the Delaware Bay the f i s h moved o f f sho re t o spawn i n the w i n t e r (Smith and Daiber 1977) Morse (1981) repor ted t h a t summer f lounder have a p ro t rac ted spawning season o f v a r i a b l e du ra t i on w i t h e a r l y maturat ion h igh fecundi ty s e r i a l spawning and ex tens ive migra t ions across the con t inen ta l she l f L i f e h i s t o r y parameters are determined by l o c a l genet ic and environmental fac tors

The number o f maturing ova i n summer f lounder i s h i g h l y co r re la ted w i t h weight and length F ish i n the Mid-At1 a n t i c Region between 366 and 680 mm TL have an est imated 046 t o 419 m i l l i o n ova (Morse 1981)

Total egg count o f w in te r f lounder ranged from 0435 m i 11 i o n f o r an age-I11 f i s h t o 3329 m i l l i o n eggs f o r an age-V f i s h captured o f f Massachusetts (Topp 1968) The reg ress ion equat ion f o r t he r e l a t i o n s h i p o f f ecund i t y t o f i s h

I n t h e S o u t h A t l a n t i c B i g h t spawning t i m e s and h a b i t a t s o f summer f 1 ounder a r e p o o r l y documented Based o n c o l l e c t i o n s o f n e w l y h a t c h e d l a r v a e commerc ia l c a t c h r a t e s and genera l i z e d c o a s t a l and she1 f t r a w l i n g s u r v e y s seasonal m i g r a t i o n p a t t e r n s o f a d u l t f i s h have been deduced I t i s known t h a t summer f l o u n d e r m i g r a t e o f f s h o r e d u r i n g c o o l e r months I n l a t e f a l l w i n t e r o r e a r l y s p r i n g t h e y spawn near t h e bo t tom o f s h e l f wa te rs 30-200 m deep The g e n e t i c a l l y d i s t i n c t p o p u l a t i o n s n o r t h and sou th o f C a p e H a t t e r a s m a y b e h a v e d i f f e r e n t l y

Between Cape Cod P~assachuset ts and Cape L o o k o u t N o r t h C a r o l i n a spawning o f summer f l o u n d e r began i n September (Smi th 1973) I n t h e s u r v e y b y S m i t h ( 1 9 7 3 ) spawning c o n t i n u e d t h r o u g h December i n t h e n o r t h e r n p a r t and t h r o u g h F e b r u a r y t o t h e south Spawn ing i n t h e Mid-At1 a n t i c Region c o n t i n u e s i n t o Februa ry and March i n some y e a r s and p r o b a b l y b e g i n s n o r t h o f C h e s a p e a k e Bay and p r o g r e s s e s southward i n a c y c l e t h a t ends i n t h e South A t l a n t i c B i g h t ( S m i t h 1973) A d u l t summer f 1 o u n d e r move b a c k i n s h o r e t o e s t u a r i e s o r c o a s t a l wa te rs i n t h e w i n t e r and s p r i n g ( W i l k e t a l 1 9 8 0 )

Spawning t imes o f the w i n t e r f lounder are var iab le l i k e those o f the summer f lounder spawning occurs f i r s t i n the southern p a r t o f the

range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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Figure 1 A Summer f lounder (Powell 1974) B Winter f lounder ( M a r t i n and Drewry 1978)

SUMMER AND WINTER FLOUNDER

Summer F l ounder

S c i e n t i f i c name P a r a l i c h t h y s d e n t a t u s

P r e f e r r e d common name Summer f l o u n a e r ( F i g u r e 1 A )

Othe r common names F lounder f l u k e p l a i c e f i s h p l a i c e p l a i s e s p l a i c e c h i c k e n ha1 i b u t f l o u n d e r o f New York common f 1 ounder b r a i l

t u r b o t f l a t f i s h l o n g t o o t h e d f l o u n - d e r

C lass Os te i ch thyes Order P leu ronec t i f o rmes Fami ly Both idae Geographic range The summer f l o u n d e r

p r e f 5 r s e s t u a r i n e and s h e l f wa te rs o f t h e A t l a n t i c Ocean I t i s found b e t w e e n N o v a S c o t i d a n d t h e s o u t h e a s t e r n c o a s t o f F l o r i d a b u t i s m o s t a b u n d a n t f r o m C a p e Cod M a s s a c h u s e t t s t o Cape H a t t e r a s N o r t h Caro l i na ( t i i 1 debrand and Schroeder 1928) D i s t r i b u t i o n i n

t h e m i d - A t l a n t i c r eg ion i s shown i n F igu re 2

W in te r F lounder

j c i e n t i f i c name P s e u d o ~ l e u r o n e c t e s ameriranus

P r e t e r r e d common name h i n t e r f 1 ounder ( F i g u r e 1 6 )

Other common names F l a t f i s h S l a c k b a c k Georges Bank f l o u n d e r 1 emon s o l e f l ounaer so le rough f 1 o u n u e r p l i e r o u g e c a r r e l e t ha1 i but ho l i but dab

C lass O s t e i c h t h y e s Order P l e u r o n e c t i f o r m e s F a m i l y P l e u r o n e c t i d a e Geographic range The w i n t e r f l o u n d e r

h a s a b road range o c c u r r i n g f rom B u t t l e Harbor and Windy T i c k l e Labrador t o Beaufor t No r th Caro l ina b u t i s most common i n es tua r i es between t h e G u l f o f S t Lawrence and Chesapeake Bay D i s t r i b u t i o n i n t h e M i d - A t l a n t i c Region i s shown i n F igu re 2

M O R P H O L O G Y I D E N T ~ F I C A T I O N AIDS

Summer F lounder

The boay 3 f t h e summer f l o l ~ n d e r i s l a t e r a l l y f l a t t e n e a a m a r g i i ~ o f t h e p r e o p e r c l e i s f r e e and t h e eyes a r e on t h e l e f t s i d e The bases c f b o t h p e l v i c f i n s a r e s h o r t The o c u l a r s i d e o f t h e f i s h ranges f rom t a n t o d a r k brown and has riunierous o c e l l a t e d spo ts F i v e p rominen t s p o t s are ar ranged i n two t r i a n g l e s w i t h a common apex on t h e l a t e r a l 1ine h o w e v e r t h i s c o n f i g u r a t i o n i s genera l 1 y 1 ack ing i n 1 a r g e r specimens The f i s h a r e a b l e t o b l e n d i n t o t h e i r background b y adap t ing t o t h e t e x t u r e and c o l o r o f t h e s u b s t r a t e on which t h e y l i v e

M e r i s t i c c h a r a c t e r i s t i c s Dorsal rays 80-98 anal rays 63-78 pec to ra l rays 10-13 ver tebrae 40-43 (Smith and Da iber 1977) g i l l r a k e r s on lower l i m b o f f i r s t arch 14-19 Average head l e n g t h and average upper

jaw l e n g t h a re conta ined 396 and 205 t imes r e s p e c t i v e l y i n s tandard 1 ength (SL) (Hi ldebrand and Schroeder 1928) The sca les a re c teno id Late p o s t l arvae o f summer f l ounde r have a we1 1 -de f ined band o f b l a c k pigment a long t h e a n t e r i o r t w o - t h i r d s o f t h e anal f i n and a s i m i l a r band along t h e a n t e r i o r f o u r - f i f t h s o f t h e dorsa l f i n (F igu re 3d) which a re l a c k i n g i n t he southern f l ounde r (Para1 i ch thvs le thos t iqma) and t h e g u l f f l ounde r (P a1 b i q u t t a ) Summer f l ounde r p o s t l arvae t y p i c a l l y have 40-42 t o t a l ver tebrae whi 1 e southern f l ounde r pos t l a r vae have 37 o r 38 and g u l f f l ounde r pos t l a r vae have 36-38 Summer f l ounde r p o s t l arvae have 81 -94 dorsa l r ays and 61-74 anal rays w h i l e gu l f f l ounde r p o s t l arvae have 72-82 dorsa l r ays and 53-63 anal r ays (Deubl e r 1958) Winter Flounder

The w i n t e r f l ounde r s body i s ovate and l a t e r a l l y compressed The eyes a re on t h e r i g h t side separated by a narrow scaled r i dge t he upper eye i s near t h e edge o f t h e head The mouth i s o f moderate s i z e and t h e l e n g t h o f t h e m a x i l l a r y on t h e b l i n d s i d e i s l e s s than o n e - t h i r d t h a t o f t h e head Winter f l ounde r a re 01 i v e green t o reddish-brown i n c o l o r and sometimes have a few r u s t y spots The l a t e r a l 1 i n e i s n e a r l y s t r a i g h t The dorsa l f i n o r i g i n a t e s oppos i te t h e forward edge o f t h e eye and i s o f n e a r l y equal h e i g h t throughout i t s 1 ength

Mer i s t i c c h a r a c t e r i s t i c s Dorsal r ays 56-81 anal r a y s 47-54 pec to ra l r ays 10-11 g i l l r a k e r s on lower l i m b o f f i r s t arch 7-8 ver tebrae 36 Average head l e n g t h i s 40 cm (Hi ldebrand and Schroeder 1928 P ie r ce and Howe 1977) The scales a re c teno id

REASON FOR INCLUSION I N SERIES

The summer f l ounde r i s an impor tan t commerci a1 and r e c r e a t i o n a l

NEW YORK

PHILADELPHIA

ATLANTIC OCEAN

M I L E S

K I L O M E T E R S

Summer flounder

Figure 2 D i s t r i b u t i o n o f t h e Summer and Winter f lounder i n t h e mid-At lant ic reg ion

3

species along the A t l a n t i c seaboard o f the Uni ted States and i s the major r e c r e a t i o n a l l y caught f lounder o f the mid-At1 a n t i c inshore waters There are th ree major commercial f i s h e r i e s the inshore summer f i she ry the o f f sho re w i n t e r f i she ry and a f a l l and w i n t e r t raw l f i she ry i n s i d e the 20-fathom (36-m) contour t h a t developed on the V i r g i n i a and North Carol ina coast i n the 1960s (Hi 1 debrand and Schroeder 1928 Scar1 e t t 1981)

weight f o r w i n t e r f lounder was as f o l l ows I

where W i s weight i n grams

South A t l a n t i c B igh t (Smith 1973) Adu l t summer f lounder move back inshore t o es tua r ies o r coastal waters i n the w i n t e r and spr ing (Wi lk e t a l 1980)

LIFE HISTORY SD awn i ng --

R e p r o d u c t i v e P h y s i o l o g y S t r a t e g y

A d u l t female summer f l o u n d e r on t h e a v e r a g e a r e 6 0 mm l o n g e r ( i n t o t a l length TL) than males a t f i r s t at ta inment o f sexual m a t u r i t y i n the Mid-At1 a n t i c B igh t (Morse 1981) The summer f lounder appears t o become sexua l ly mature by the age o f I 1 (Morse 1981) Gonads o f summer f lounder r ipened from mid-August through November i n the Delaware Bay the f i s h moved o f f sho re t o spawn i n the w i n t e r (Smith and Daiber 1977) Morse (1981) repor ted t h a t summer f lounder have a p ro t rac ted spawning season o f v a r i a b l e du ra t i on w i t h e a r l y maturat ion h igh fecundi ty s e r i a l spawning and ex tens ive migra t ions across the con t inen ta l she l f L i f e h i s t o r y parameters are determined by l o c a l genet ic and environmental fac tors

The number o f maturing ova i n summer f lounder i s h i g h l y co r re la ted w i t h weight and length F ish i n the Mid-At1 a n t i c Region between 366 and 680 mm TL have an est imated 046 t o 419 m i l l i o n ova (Morse 1981)

Total egg count o f w in te r f lounder ranged from 0435 m i 11 i o n f o r an age-I11 f i s h t o 3329 m i l l i o n eggs f o r an age-V f i s h captured o f f Massachusetts (Topp 1968) The reg ress ion equat ion f o r t he r e l a t i o n s h i p o f f ecund i t y t o f i s h

I n t h e S o u t h A t l a n t i c B i g h t spawning t i m e s and h a b i t a t s o f summer f 1 ounder a r e p o o r l y documented Based o n c o l l e c t i o n s o f n e w l y h a t c h e d l a r v a e commerc ia l c a t c h r a t e s and genera l i z e d c o a s t a l and she1 f t r a w l i n g s u r v e y s seasonal m i g r a t i o n p a t t e r n s o f a d u l t f i s h have been deduced I t i s known t h a t summer f l o u n d e r m i g r a t e o f f s h o r e d u r i n g c o o l e r months I n l a t e f a l l w i n t e r o r e a r l y s p r i n g t h e y spawn near t h e bo t tom o f s h e l f wa te rs 30-200 m deep The g e n e t i c a l l y d i s t i n c t p o p u l a t i o n s n o r t h and sou th o f C a p e H a t t e r a s m a y b e h a v e d i f f e r e n t l y

Between Cape Cod P~assachuset ts and Cape L o o k o u t N o r t h C a r o l i n a spawning o f summer f l o u n d e r began i n September (Smi th 1973) I n t h e s u r v e y b y S m i t h ( 1 9 7 3 ) spawning c o n t i n u e d t h r o u g h December i n t h e n o r t h e r n p a r t and t h r o u g h F e b r u a r y t o t h e south Spawn ing i n t h e Mid-At1 a n t i c Region c o n t i n u e s i n t o Februa ry and March i n some y e a r s and p r o b a b l y b e g i n s n o r t h o f C h e s a p e a k e Bay and p r o g r e s s e s southward i n a c y c l e t h a t ends i n t h e South A t l a n t i c B i g h t ( S m i t h 1973) A d u l t summer f 1 o u n d e r move b a c k i n s h o r e t o e s t u a r i e s o r c o a s t a l wa te rs i n t h e w i n t e r and s p r i n g ( W i l k e t a l 1 9 8 0 )

Spawning t imes o f the w i n t e r f lounder are var iab le l i k e those o f the summer f lounder spawning occurs f i r s t i n the southern p a r t o f the

range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987b Mar ine r e c r e a t i o n a l f i s h e r y s t a t i s t i c s survey A t l a n t i c and g u l f coas ts 1986 US N a t l Mar F i s h Serv Cur r F i s h S t a t 8392

O l l a BL R Wicklund and S Wilk 1969 Behavior o f winter f lounder i n a natura l h a b i t a t Trans Am Fish Soc 98717-720

O l l a BL CE Samet and AL Studholme 1972 A c t i v i t y and feeding behavior o f the summer flounder (Paral i c h t h v ~ dentatus) under c o n t r o l 1 ed 1 abora to ry conditions Fish B u l l 701127- 1136

P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

t h e m i d - A t l a n t i c r eg ion i s shown i n F igu re 2

W in te r F lounder

j c i e n t i f i c name P s e u d o ~ l e u r o n e c t e s ameriranus

P r e t e r r e d common name h i n t e r f 1 ounder ( F i g u r e 1 6 )

Other common names F l a t f i s h S l a c k b a c k Georges Bank f l o u n d e r 1 emon s o l e f l ounaer so le rough f 1 o u n u e r p l i e r o u g e c a r r e l e t ha1 i but ho l i but dab

C lass O s t e i c h t h y e s Order P l e u r o n e c t i f o r m e s F a m i l y P l e u r o n e c t i d a e Geographic range The w i n t e r f l o u n d e r

h a s a b road range o c c u r r i n g f rom B u t t l e Harbor and Windy T i c k l e Labrador t o Beaufor t No r th Caro l ina b u t i s most common i n es tua r i es between t h e G u l f o f S t Lawrence and Chesapeake Bay D i s t r i b u t i o n i n t h e M i d - A t l a n t i c Region i s shown i n F igu re 2

M O R P H O L O G Y I D E N T ~ F I C A T I O N AIDS

Summer F lounder

The boay 3 f t h e summer f l o l ~ n d e r i s l a t e r a l l y f l a t t e n e a a m a r g i i ~ o f t h e p r e o p e r c l e i s f r e e and t h e eyes a r e on t h e l e f t s i d e The bases c f b o t h p e l v i c f i n s a r e s h o r t The o c u l a r s i d e o f t h e f i s h ranges f rom t a n t o d a r k brown and has riunierous o c e l l a t e d spo ts F i v e p rominen t s p o t s are ar ranged i n two t r i a n g l e s w i t h a common apex on t h e l a t e r a l 1ine h o w e v e r t h i s c o n f i g u r a t i o n i s genera l 1 y 1 ack ing i n 1 a r g e r specimens The f i s h a r e a b l e t o b l e n d i n t o t h e i r background b y adap t ing t o t h e t e x t u r e and c o l o r o f t h e s u b s t r a t e on which t h e y l i v e

M e r i s t i c c h a r a c t e r i s t i c s Dorsal rays 80-98 anal rays 63-78 pec to ra l rays 10-13 ver tebrae 40-43 (Smith and Da iber 1977) g i l l r a k e r s on lower l i m b o f f i r s t arch 14-19 Average head l e n g t h and average upper

jaw l e n g t h a re conta ined 396 and 205 t imes r e s p e c t i v e l y i n s tandard 1 ength (SL) (Hi ldebrand and Schroeder 1928) The sca les a re c teno id Late p o s t l arvae o f summer f l ounde r have a we1 1 -de f ined band o f b l a c k pigment a long t h e a n t e r i o r t w o - t h i r d s o f t h e anal f i n and a s i m i l a r band along t h e a n t e r i o r f o u r - f i f t h s o f t h e dorsa l f i n (F igu re 3d) which a re l a c k i n g i n t he southern f l ounde r (Para1 i ch thvs le thos t iqma) and t h e g u l f f l ounde r (P a1 b i q u t t a ) Summer f l ounde r p o s t l arvae t y p i c a l l y have 40-42 t o t a l ver tebrae whi 1 e southern f l ounde r pos t l a r vae have 37 o r 38 and g u l f f l ounde r pos t l a r vae have 36-38 Summer f l ounde r p o s t l arvae have 81 -94 dorsa l r ays and 61-74 anal rays w h i l e gu l f f l ounde r p o s t l arvae have 72-82 dorsa l r ays and 53-63 anal r ays (Deubl e r 1958) Winter Flounder

The w i n t e r f l ounde r s body i s ovate and l a t e r a l l y compressed The eyes a re on t h e r i g h t side separated by a narrow scaled r i dge t he upper eye i s near t h e edge o f t h e head The mouth i s o f moderate s i z e and t h e l e n g t h o f t h e m a x i l l a r y on t h e b l i n d s i d e i s l e s s than o n e - t h i r d t h a t o f t h e head Winter f l ounde r a re 01 i v e green t o reddish-brown i n c o l o r and sometimes have a few r u s t y spots The l a t e r a l 1 i n e i s n e a r l y s t r a i g h t The dorsa l f i n o r i g i n a t e s oppos i te t h e forward edge o f t h e eye and i s o f n e a r l y equal h e i g h t throughout i t s 1 ength

Mer i s t i c c h a r a c t e r i s t i c s Dorsal r ays 56-81 anal r a y s 47-54 pec to ra l r ays 10-11 g i l l r a k e r s on lower l i m b o f f i r s t arch 7-8 ver tebrae 36 Average head l e n g t h i s 40 cm (Hi ldebrand and Schroeder 1928 P ie r ce and Howe 1977) The scales a re c teno id

REASON FOR INCLUSION I N SERIES

The summer f l ounde r i s an impor tan t commerci a1 and r e c r e a t i o n a l

NEW YORK

PHILADELPHIA

ATLANTIC OCEAN

M I L E S

K I L O M E T E R S

Summer flounder

Figure 2 D i s t r i b u t i o n o f t h e Summer and Winter f lounder i n t h e mid-At lant ic reg ion

3

species along the A t l a n t i c seaboard o f the Uni ted States and i s the major r e c r e a t i o n a l l y caught f lounder o f the mid-At1 a n t i c inshore waters There are th ree major commercial f i s h e r i e s the inshore summer f i she ry the o f f sho re w i n t e r f i she ry and a f a l l and w i n t e r t raw l f i she ry i n s i d e the 20-fathom (36-m) contour t h a t developed on the V i r g i n i a and North Carol ina coast i n the 1960s (Hi 1 debrand and Schroeder 1928 Scar1 e t t 1981)

weight f o r w i n t e r f lounder was as f o l l ows I

where W i s weight i n grams

South A t l a n t i c B igh t (Smith 1973) Adu l t summer f lounder move back inshore t o es tua r ies o r coastal waters i n the w i n t e r and spr ing (Wi lk e t a l 1980)

LIFE HISTORY SD awn i ng --

R e p r o d u c t i v e P h y s i o l o g y S t r a t e g y

A d u l t female summer f l o u n d e r on t h e a v e r a g e a r e 6 0 mm l o n g e r ( i n t o t a l length TL) than males a t f i r s t at ta inment o f sexual m a t u r i t y i n the Mid-At1 a n t i c B igh t (Morse 1981) The summer f lounder appears t o become sexua l ly mature by the age o f I 1 (Morse 1981) Gonads o f summer f lounder r ipened from mid-August through November i n the Delaware Bay the f i s h moved o f f sho re t o spawn i n the w i n t e r (Smith and Daiber 1977) Morse (1981) repor ted t h a t summer f lounder have a p ro t rac ted spawning season o f v a r i a b l e du ra t i on w i t h e a r l y maturat ion h igh fecundi ty s e r i a l spawning and ex tens ive migra t ions across the con t inen ta l she l f L i f e h i s t o r y parameters are determined by l o c a l genet ic and environmental fac tors

The number o f maturing ova i n summer f lounder i s h i g h l y co r re la ted w i t h weight and length F ish i n the Mid-At1 a n t i c Region between 366 and 680 mm TL have an est imated 046 t o 419 m i l l i o n ova (Morse 1981)

Total egg count o f w in te r f lounder ranged from 0435 m i 11 i o n f o r an age-I11 f i s h t o 3329 m i l l i o n eggs f o r an age-V f i s h captured o f f Massachusetts (Topp 1968) The reg ress ion equat ion f o r t he r e l a t i o n s h i p o f f ecund i t y t o f i s h

I n t h e S o u t h A t l a n t i c B i g h t spawning t i m e s and h a b i t a t s o f summer f 1 ounder a r e p o o r l y documented Based o n c o l l e c t i o n s o f n e w l y h a t c h e d l a r v a e commerc ia l c a t c h r a t e s and genera l i z e d c o a s t a l and she1 f t r a w l i n g s u r v e y s seasonal m i g r a t i o n p a t t e r n s o f a d u l t f i s h have been deduced I t i s known t h a t summer f l o u n d e r m i g r a t e o f f s h o r e d u r i n g c o o l e r months I n l a t e f a l l w i n t e r o r e a r l y s p r i n g t h e y spawn near t h e bo t tom o f s h e l f wa te rs 30-200 m deep The g e n e t i c a l l y d i s t i n c t p o p u l a t i o n s n o r t h and sou th o f C a p e H a t t e r a s m a y b e h a v e d i f f e r e n t l y

Between Cape Cod P~assachuset ts and Cape L o o k o u t N o r t h C a r o l i n a spawning o f summer f l o u n d e r began i n September (Smi th 1973) I n t h e s u r v e y b y S m i t h ( 1 9 7 3 ) spawning c o n t i n u e d t h r o u g h December i n t h e n o r t h e r n p a r t and t h r o u g h F e b r u a r y t o t h e south Spawn ing i n t h e Mid-At1 a n t i c Region c o n t i n u e s i n t o Februa ry and March i n some y e a r s and p r o b a b l y b e g i n s n o r t h o f C h e s a p e a k e Bay and p r o g r e s s e s southward i n a c y c l e t h a t ends i n t h e South A t l a n t i c B i g h t ( S m i t h 1973) A d u l t summer f 1 o u n d e r move b a c k i n s h o r e t o e s t u a r i e s o r c o a s t a l wa te rs i n t h e w i n t e r and s p r i n g ( W i l k e t a l 1 9 8 0 )

Spawning t imes o f the w i n t e r f lounder are var iab le l i k e those o f the summer f lounder spawning occurs f i r s t i n the southern p a r t o f the

range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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B r e d e r C M J r 1 9 2 4 Some embryonic and l a r v a l s tages o f t h e w i n t e r f l o u n d e r B u l l US Bur F i s h 38311-315

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Fletcher G L J W Kiceni uk and V P Will iams 1981 E f fec ts o f o i l e d sediments on mor ta l i t y feeding and growth o f w i n t e r f l o u n d e r (Pseudo~ l euronectes americanus) Mar Ecol Prog Ser 491-96

H i 1 debrand S F and WC Schroeder 1928 F i s h e s o f t h e Chesapeake Bay US B u r e a u o f F i s h e r i e s 1024366 PP

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J o h n s I WH H o w e l l and S K l e i n - F a c P h e e 1 9 8 1 Y o l k u t i l i z a t i o n and g rowth t o y o l k sac a b s o r p t i o n i n summer f l o u n d e r ( P a r a l i c h t h y s d e n t a t u s ) l a r v a e a t c o n s t a n t and c y c l i c tempera tu res K a r B i o l ( B e r l ) 63301-330

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N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987b Mar ine r e c r e a t i o n a l f i s h e r y s t a t i s t i c s survey A t l a n t i c and g u l f coas ts 1986 US N a t l Mar F i s h Serv Cur r F i s h S t a t 8392

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P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

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~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

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R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

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NEW YORK

PHILADELPHIA

ATLANTIC OCEAN

M I L E S

K I L O M E T E R S

Summer flounder

Figure 2 D i s t r i b u t i o n o f t h e Summer and Winter f lounder i n t h e mid-At lant ic reg ion

3

species along the A t l a n t i c seaboard o f the Uni ted States and i s the major r e c r e a t i o n a l l y caught f lounder o f the mid-At1 a n t i c inshore waters There are th ree major commercial f i s h e r i e s the inshore summer f i she ry the o f f sho re w i n t e r f i she ry and a f a l l and w i n t e r t raw l f i she ry i n s i d e the 20-fathom (36-m) contour t h a t developed on the V i r g i n i a and North Carol ina coast i n the 1960s (Hi 1 debrand and Schroeder 1928 Scar1 e t t 1981)

weight f o r w i n t e r f lounder was as f o l l ows I

where W i s weight i n grams

South A t l a n t i c B igh t (Smith 1973) Adu l t summer f lounder move back inshore t o es tua r ies o r coastal waters i n the w i n t e r and spr ing (Wi lk e t a l 1980)

LIFE HISTORY SD awn i ng --

R e p r o d u c t i v e P h y s i o l o g y S t r a t e g y

A d u l t female summer f l o u n d e r on t h e a v e r a g e a r e 6 0 mm l o n g e r ( i n t o t a l length TL) than males a t f i r s t at ta inment o f sexual m a t u r i t y i n the Mid-At1 a n t i c B igh t (Morse 1981) The summer f lounder appears t o become sexua l ly mature by the age o f I 1 (Morse 1981) Gonads o f summer f lounder r ipened from mid-August through November i n the Delaware Bay the f i s h moved o f f sho re t o spawn i n the w i n t e r (Smith and Daiber 1977) Morse (1981) repor ted t h a t summer f lounder have a p ro t rac ted spawning season o f v a r i a b l e du ra t i on w i t h e a r l y maturat ion h igh fecundi ty s e r i a l spawning and ex tens ive migra t ions across the con t inen ta l she l f L i f e h i s t o r y parameters are determined by l o c a l genet ic and environmental fac tors

The number o f maturing ova i n summer f lounder i s h i g h l y co r re la ted w i t h weight and length F ish i n the Mid-At1 a n t i c Region between 366 and 680 mm TL have an est imated 046 t o 419 m i l l i o n ova (Morse 1981)

Total egg count o f w in te r f lounder ranged from 0435 m i 11 i o n f o r an age-I11 f i s h t o 3329 m i l l i o n eggs f o r an age-V f i s h captured o f f Massachusetts (Topp 1968) The reg ress ion equat ion f o r t he r e l a t i o n s h i p o f f ecund i t y t o f i s h

I n t h e S o u t h A t l a n t i c B i g h t spawning t i m e s and h a b i t a t s o f summer f 1 ounder a r e p o o r l y documented Based o n c o l l e c t i o n s o f n e w l y h a t c h e d l a r v a e commerc ia l c a t c h r a t e s and genera l i z e d c o a s t a l and she1 f t r a w l i n g s u r v e y s seasonal m i g r a t i o n p a t t e r n s o f a d u l t f i s h have been deduced I t i s known t h a t summer f l o u n d e r m i g r a t e o f f s h o r e d u r i n g c o o l e r months I n l a t e f a l l w i n t e r o r e a r l y s p r i n g t h e y spawn near t h e bo t tom o f s h e l f wa te rs 30-200 m deep The g e n e t i c a l l y d i s t i n c t p o p u l a t i o n s n o r t h and sou th o f C a p e H a t t e r a s m a y b e h a v e d i f f e r e n t l y

Between Cape Cod P~assachuset ts and Cape L o o k o u t N o r t h C a r o l i n a spawning o f summer f l o u n d e r began i n September (Smi th 1973) I n t h e s u r v e y b y S m i t h ( 1 9 7 3 ) spawning c o n t i n u e d t h r o u g h December i n t h e n o r t h e r n p a r t and t h r o u g h F e b r u a r y t o t h e south Spawn ing i n t h e Mid-At1 a n t i c Region c o n t i n u e s i n t o Februa ry and March i n some y e a r s and p r o b a b l y b e g i n s n o r t h o f C h e s a p e a k e Bay and p r o g r e s s e s southward i n a c y c l e t h a t ends i n t h e South A t l a n t i c B i g h t ( S m i t h 1973) A d u l t summer f 1 o u n d e r move b a c k i n s h o r e t o e s t u a r i e s o r c o a s t a l wa te rs i n t h e w i n t e r and s p r i n g ( W i l k e t a l 1 9 8 0 )

Spawning t imes o f the w i n t e r f lounder are var iab le l i k e those o f the summer f lounder spawning occurs f i r s t i n the southern p a r t o f the

range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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species along the A t l a n t i c seaboard o f the Uni ted States and i s the major r e c r e a t i o n a l l y caught f lounder o f the mid-At1 a n t i c inshore waters There are th ree major commercial f i s h e r i e s the inshore summer f i she ry the o f f sho re w i n t e r f i she ry and a f a l l and w i n t e r t raw l f i she ry i n s i d e the 20-fathom (36-m) contour t h a t developed on the V i r g i n i a and North Carol ina coast i n the 1960s (Hi 1 debrand and Schroeder 1928 Scar1 e t t 1981)

weight f o r w i n t e r f lounder was as f o l l ows I

where W i s weight i n grams

South A t l a n t i c B igh t (Smith 1973) Adu l t summer f lounder move back inshore t o es tua r ies o r coastal waters i n the w i n t e r and spr ing (Wi lk e t a l 1980)

LIFE HISTORY SD awn i ng --

R e p r o d u c t i v e P h y s i o l o g y S t r a t e g y

A d u l t female summer f l o u n d e r on t h e a v e r a g e a r e 6 0 mm l o n g e r ( i n t o t a l length TL) than males a t f i r s t at ta inment o f sexual m a t u r i t y i n the Mid-At1 a n t i c B igh t (Morse 1981) The summer f lounder appears t o become sexua l ly mature by the age o f I 1 (Morse 1981) Gonads o f summer f lounder r ipened from mid-August through November i n the Delaware Bay the f i s h moved o f f sho re t o spawn i n the w i n t e r (Smith and Daiber 1977) Morse (1981) repor ted t h a t summer f lounder have a p ro t rac ted spawning season o f v a r i a b l e du ra t i on w i t h e a r l y maturat ion h igh fecundi ty s e r i a l spawning and ex tens ive migra t ions across the con t inen ta l she l f L i f e h i s t o r y parameters are determined by l o c a l genet ic and environmental fac tors

The number o f maturing ova i n summer f lounder i s h i g h l y co r re la ted w i t h weight and length F ish i n the Mid-At1 a n t i c Region between 366 and 680 mm TL have an est imated 046 t o 419 m i l l i o n ova (Morse 1981)

Total egg count o f w in te r f lounder ranged from 0435 m i 11 i o n f o r an age-I11 f i s h t o 3329 m i l l i o n eggs f o r an age-V f i s h captured o f f Massachusetts (Topp 1968) The reg ress ion equat ion f o r t he r e l a t i o n s h i p o f f ecund i t y t o f i s h

I n t h e S o u t h A t l a n t i c B i g h t spawning t i m e s and h a b i t a t s o f summer f 1 ounder a r e p o o r l y documented Based o n c o l l e c t i o n s o f n e w l y h a t c h e d l a r v a e commerc ia l c a t c h r a t e s and genera l i z e d c o a s t a l and she1 f t r a w l i n g s u r v e y s seasonal m i g r a t i o n p a t t e r n s o f a d u l t f i s h have been deduced I t i s known t h a t summer f l o u n d e r m i g r a t e o f f s h o r e d u r i n g c o o l e r months I n l a t e f a l l w i n t e r o r e a r l y s p r i n g t h e y spawn near t h e bo t tom o f s h e l f wa te rs 30-200 m deep The g e n e t i c a l l y d i s t i n c t p o p u l a t i o n s n o r t h and sou th o f C a p e H a t t e r a s m a y b e h a v e d i f f e r e n t l y

Between Cape Cod P~assachuset ts and Cape L o o k o u t N o r t h C a r o l i n a spawning o f summer f l o u n d e r began i n September (Smi th 1973) I n t h e s u r v e y b y S m i t h ( 1 9 7 3 ) spawning c o n t i n u e d t h r o u g h December i n t h e n o r t h e r n p a r t and t h r o u g h F e b r u a r y t o t h e south Spawn ing i n t h e Mid-At1 a n t i c Region c o n t i n u e s i n t o Februa ry and March i n some y e a r s and p r o b a b l y b e g i n s n o r t h o f C h e s a p e a k e Bay and p r o g r e s s e s southward i n a c y c l e t h a t ends i n t h e South A t l a n t i c B i g h t ( S m i t h 1973) A d u l t summer f 1 o u n d e r move b a c k i n s h o r e t o e s t u a r i e s o r c o a s t a l wa te rs i n t h e w i n t e r and s p r i n g ( W i l k e t a l 1 9 8 0 )

Spawning t imes o f the w i n t e r f lounder are var iab le l i k e those o f the summer f lounder spawning occurs f i r s t i n the southern p a r t o f the

range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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range and progress ive ly l a t e r towards the n o r t h i n keeping w i t h water temperatures Spawning occurs inshore from November through June from Newfound1 and t o Del aware Ma1 e w i n t e r f lounder i n nor thern (Canadian) waters showed spermatogenesis and gonad development 6 months before the spawning season (which was i n May t o June) Oocytes may take th ree years t o mature Nonreproduct ive i n d i v i d u a l s occur i n the spawning season bu t c o n d i t i o n fac to rs are 1 ess i n these f i s h They may be conserving resources t o spawn a f t e r a l a t e r feeding season w i t h abundant food where t h e i r cond i t i on f a c t o r i s h igher (Burton and I d l e r 1984)

S a i l a (1961) showed w i t h t a g g i n g s t u d i e s t h a t w i n t e r f l o u n d e r r e t u r n e d t o t h e t a g g i n g l o c a l i t y w i t h h i g h f r e q u e n c y o v e r one yea r o f r e c o v e r y d a t a F i s h d i s p e r s e d f r o m t h e b r e e d i n g g r o u n d s i n summer a n d r e t u r n e d i n w i n t e r The same b r e e d i n g a r e a was n o t a l w a y s s u c c e s s f u l l y l o c a t e d ( S a i l a 1961)

W in te r f l o u n d e r spawn i n s h a l l o w i n s h o r e wa te rs ( J e f f r i es and Johnson 1 9 7 4 ) Spawn ing o c c u r s a t n i g h t ( B r e d e r 1 9 2 2 ) I n o b s e r v a t i o n s b y B r e d e r ( 1 9 2 2 ) i n t h e l a b o r a t o r y s p a w n i n g i s p r e c e d e d b y e x t e n s i v e swimming i n s p i r a l s The f e m a l e s e x t r u d e eggs i n w ide c o u n t e r c l o c k w i s e s p i r a l s due t o t h e c e n t r i f u g a l f o r c e (B reder 1922)

Eggs o f the summer f lounder are pe lag ic Incubat ion t ime i n the l abo ra to ry was 9 days a t 5 C and 2-3 days a t 21 C Mean diameter o f mature u n f e r t i l i z e d eggs i s 098 mm Yolk occupies about 95 o f t he egg volume (Johns e t a1 1981)

Winter f lounder eggs are minute demersal and adhesive s ink ing t o the bottom (Breder 1924) The adhesive eggs averaged 081 mm (Breder 1924) o r 061 mm (Topp 1968) i n modal diameter

They clump together a f t e r f e r t i l i - zat ion thus o f t e n becoming d i s t o r t e d and ovoid i n shape (Breder 1924)

Larvae

N o t o c h o r d l e n g t h o f summer f l o u n d e r was about 30 mm a t h a t c h i n g i n t h e l a b o r a t o r y and was about 36 m when yo1 k-sac a b s o r p t i o n was comp le te (Johns e t a l 1981) Growth u n t i l t h e a b s o r p t i o n o f t h e yo1 k sac i s comp le te i s n o t t e m p e r a t u r e dependent La rvae t h a t h a t c h a t b o t h 11 OC and 2 1 OC

grow t o about 36 mm n o t o c h o r d l e n g t h w i t h i n 6 days a f t e r h a t c h i n g (Johns e t a1 1981) No d a t a on l a r v a l f e e d i n g h a b i t s i s a v a i l a b l e

Larvae o f summer f lounder are t ranspor ted t o es tuar ine nursery areas by cur rents Greater dens i t i es o f young f i s h were found i n o r near i n l e t s and g rea te r numbers were captured du r ing per iods o f t h e f u l l moon (Wi 11 i ams and Deubl e r 1968)

I n l a r v a l w i n t e r f l o u n d e r ( 7 mm TL) t h e d i g e s t i v e t r a c t i s c o m p l e t e l y deve loped t h e eyes a r e pigmented and t h e m o u t h i s f u l l y f u n c t i o n a l (Su l 1 i v a n 1914)

S u l l i v a n ( 1 9 1 4 ) who d e s c r i b e d t h e w i n t e r f l o u n d e r l a r v a f r o m h a t c h i n g t o t h e e n d o f t h e second month i n t h e l a b o r a t o r y d i v i d e d i t s 1 a r v a l h i s t o r y i n t o f o u r s tages which h e s e l e c t e d t o show d i a g n o s t i c c h a r a c t e r i s t i c s f o r i d e n t i f i c a t i o n

S t a g e I - A g r o u p o f da rk p igment

s p o t s on t h e p o s t e r i o r h a l f o f t h e body i s t h e most impor tant c h a r a c t e r f o r i d e n t i f i c a t i o n The n o t o c h o r d i s p r e s e n t as a s t r a i g h t tube Yo1 k a b s o r p t i o n i s g r a d u a l a n d v a r i e s w i t h tempera tu re

Stage I 1 - Yolk absorbed age 12 days l e n g t h 5 mn

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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J e f f r i e s HP and W C Johnson 1974 S e a s o n a l d i s t r i b u t i o n s o f b o t t o m f i s h e s i n t h e N a r r a g a n s e t t 3ay area seven-year v a r i a t i o n s n t h e a ~ u n d a n c e o f w i n t e r f l o u n d e r (Pseudopl eu ronec tes americanus) J F i s h Res 3oard Can 311057- i066

J o h n s I WH H o w e l l and S K l e i n - F a c P h e e 1 9 8 1 Y o l k u t i l i z a t i o n and g rowth t o y o l k sac a b s o r p t i o n i n summer f l o u n d e r ( P a r a l i c h t h y s d e n t a t u s ) l a r v a e a t c o n s t a n t and c y c l i c tempera tu res K a r B i o l ( B e r l ) 63301-330

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L a u r e n c e G C 1975 L a b o r a t o r y g r o w t h and me tabo l i sm o f t h e w i n t e r f 1 o u n d e r P s e u d o p l e u r o n e c t e s a m e r i c a n u s f r o m h a t c h i n g t h r o u g h metamorphosis a t t h r e e tempera tu res Mar B i o l ( B e r l ) 32223-229

Lev ings CD 1974 Seasonal changes i n f e e d i n g and p a r t i c l e s e l e c t i o n b y

w i n t e r f l o u n d e r (Pseudopl eu ronec tes amer icanus) Trans Am F i s h Soc 103828-832

M a r t i n FD and GE Drewry 1978 Deve lopment of f i s h e s o f t h e Mid- A t l a n t i c B i g h t an a t l a s o f egg 1 a r v a l and juven i 1 e s tages Vol V I S t r o m a t e i d a e t h r o u g h Ogocepha l i d a e US F i s h W i l d l Serv B i o l Serv Program FWSOBS- 7812 416 pp

McCracken FD 1963 Seasonal movements o f the w in te r f lounder P s e u d o ~ l e u r o n e c t e s americanus (Walbaum) on the A t l a n t i c coast J Fish Res Board Can 20551-586

Morse W W 1981 Reproduc t i on o f t h e summer f l o u n d e r P a r a l i c h t h s d e n t a t u s ( L J d 19189-203

r i a t i o n a l Y a r i n e F i s h e r i e s S e r v i c e 1980 F i s h e r y S t a t i s t i c s o f t h e U n i t e d S t a t e s 1979 US N a t l Far F i s h Serv Cur r F i s h S t a t NO aooo

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N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987b Mar ine r e c r e a t i o n a l f i s h e r y s t a t i s t i c s survey A t l a n t i c and g u l f coas ts 1986 US N a t l Mar F i s h Serv Cur r F i s h S t a t 8392

O l l a BL R Wicklund and S Wilk 1969 Behavior o f winter f lounder i n a natura l h a b i t a t Trans Am Fish Soc 98717-720

O l l a BL CE Samet and AL Studholme 1972 A c t i v i t y and feeding behavior o f the summer flounder (Paral i c h t h v ~ dentatus) under c o n t r o l 1 ed 1 abora to ry conditions Fish B u l l 701127- 1136

P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

Stage I 1 1 - Metamorphosing l a r v a 5-7 weeks o l d and 58 mm long

S t a g e I V - P o s t l a r v a about 8 weeks o l d and 65 mm l o n g average body dep th 275 mm

J u v e n i l e s

Young summer f l o u n d e r a r e gt6 mm l o n g when t h e y f i r s t m o v e i n t o e s t u a r i e s ( W e i n s t e i n e t a1 1980) I n t h e Cape F e a r R i v e r Es tua ry N o r t h C a r o l i n a p o s t l a r v a e f i r s t e n t e r e d t h e m a r s h e s i n M a r c h a n d A p r i l ( W e i n s t e i n 1 9 7 9 ) P r i o r t o l a t e summer j u v e n i l e summer f 1 ounder were r a n d o m l y d i s t r i b u t e d i n an es tua ry b u t i n 1 a t e summer and e a r l y f a l l t h e y w e r e m o r e a b u n d a n t i n a n e s t u a r i n e sea g r a s s bed t h a n i n an a d j a c e n t t i d a l marsh c reek ( We ins te in and Brooks 1983)

No p o s t l a r v a l summer f l o u n d e r h a v e been c o l l e c t e d a t s a l i n i t i e s b e l o w 1 2 p p t i n t h e heuse R i v e r b a s i n N o r t h C a r o l i n a ( K e u p and Bay1 e s s 1 9 6 4 ) However j u v e n i 1 es w e r e p r e v a1 e n t a t h i g h e r s a l i n i t i e s (Powel 1 and Schwartz 1979) Pam1 i c o Sound and a d j a c e n t e s t u a r i e s a r e i m p o r t a n t n u r s e r y areas f o r summer f l o u n d e r ( P o w e l l and Schwartz 1977) Y e a r l i n g s move t o t h e o c e a n i n summer b u t u n d e r y e a r l i n g s r e m a i n i n t h e e s t u a r i e s (Powe l l and Schwartz 1977)

F o r t h e f i r s t s u m m e r y o u n g - o f - y e a r w i n t e r f l o u n d e r remain i n s h a l 1 ow w a t e r s o f b a y s and e s t u a r i e s w h e r e t h e y were spawned Sandy c o v e s a p p e a r t o be p r e f e r r e d hab i ta t s o f these f i s h (Hi ldebrand and Schroeder 1928)

The j u v e n i l e s are preyed upon by summer f lounder s t r i p e d bass b lue f i sh and o the r species o f f i s h o f 1 arger s ize cormorants and harbor seals are a1 so predators The young are found from June through November from Myst ic River Connecticut t o

Long I s land Sound I n t h e Upper Myst ic Estuary and Long I s land Sound between J u l y and February t he average leng th o f t he young was 23 mm TL (Pearcy 1962) Juveni 1 es have been observed year-round i n Long I s1 and Sound and are abundant from June t o October i n Shi nnecock and Peconic Bay Long I s1 and March through November i s a peak per iod i n the Delaware River Estuary O f f Massachusetts on l y about 73 o f t h e j u v e n i l e s moved o f fshore i n t h e spr ing and summer seaward m ig ra t i on (Howe e t a l 1976) I n Narragansett Bay Rhode Is land smal ler f i s h (10-20 cm long) do no t migrate beyond the headlands i n spr ing ( J e f f r i e s and Johnson 1974)

See F i g u r e s 3 and 4 f o r genera l deve lopment o f b o t h spec ies

A d u l t s

S a i 1 a e t a1 ( 1 9 6 5 ) p r e p a r e d age-weight t a b l e s f o r w i n t e r f l o u n d e r

caught i n Char les town Pond and h a r r a - g a n s e t t B a y R h o d e I s l a n d The average w e i g h t o f 12 -yea r -o ld s p e c i - mens was c a l c u l a t e d t o be 8 7 4 g The l a r g e s t r e c o r d e d a d u l t was 570 mm ( T L ) and was p r o b a b l y c o n s i d e r a b l y o l d e r t h a n 12 y e a r s ( B i g e l o w and Schroeder 1953)

O f f southern Massachusetts w in te r f lounder moved seaward t o deeper water i n the spr ing and summer months bu t usua l l y remained w i t h i n the 55-m depth contour (Howe and Coates 1975) This seaward movement may have been an avoidance o f the temperature r i s e i n the nearshore waters

Annual na tu ra l morta l i t y r a t e fo r w in te r f lounder i n the Mid-At1 a n t i c Region was est imated a t 27 (Howe and Coates 1975) Winter f lounder dominated the catch o f a research t raw l and represented 50-90 of a l l i n d i v i d u a l s i n Narragansett Bay ( J e f f r i e s and Johnson 1974)

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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Lev ings CD 1974 Seasonal changes i n f e e d i n g and p a r t i c l e s e l e c t i o n b y

w i n t e r f l o u n d e r (Pseudopl eu ronec tes amer icanus) Trans Am F i s h Soc 103828-832

M a r t i n FD and GE Drewry 1978 Deve lopment of f i s h e s o f t h e Mid- A t l a n t i c B i g h t an a t l a s o f egg 1 a r v a l and juven i 1 e s tages Vol V I S t r o m a t e i d a e t h r o u g h Ogocepha l i d a e US F i s h W i l d l Serv B i o l Serv Program FWSOBS- 7812 416 pp

McCracken FD 1963 Seasonal movements o f the w in te r f lounder P s e u d o ~ l e u r o n e c t e s americanus (Walbaum) on the A t l a n t i c coast J Fish Res Board Can 20551-586

Morse W W 1981 Reproduc t i on o f t h e summer f l o u n d e r P a r a l i c h t h s d e n t a t u s ( L J d 19189-203

r i a t i o n a l Y a r i n e F i s h e r i e s S e r v i c e 1980 F i s h e r y S t a t i s t i c s o f t h e U n i t e d S t a t e s 1979 US N a t l Far F i s h Serv Cur r F i s h S t a t NO aooo

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987a F i s h e r i e s o f t h e U n i t e d S ta tes 1486 08 N a t l Mar F i s h Serv Cur r F i s h S t a t 8385

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987b Mar ine r e c r e a t i o n a l f i s h e r y s t a t i s t i c s survey A t l a n t i c and g u l f coas ts 1986 US N a t l Mar F i s h Serv Cur r F i s h S t a t 8392

O l l a BL R Wicklund and S Wilk 1969 Behavior o f winter f lounder i n a natura l h a b i t a t Trans Am Fish Soc 98717-720

O l l a BL CE Samet and AL Studholme 1972 A c t i v i t y and feeding behavior o f the summer flounder (Paral i c h t h v ~ dentatus) under c o n t r o l 1 ed 1 abora to ry conditions Fish B u l l 701127- 1136

P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

F i g u r e 3 The general developnent f o r t h e summer f l ounde r from ha t ch ing t o a d u l t ( F k r t i n and Drewry 1978)

7

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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r i a t i o n a l Y a r i n e F i s h e r i e s S e r v i c e 1980 F i s h e r y S t a t i s t i c s o f t h e U n i t e d S t a t e s 1979 US N a t l Far F i s h Serv Cur r F i s h S t a t NO aooo

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P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

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a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

F i g u r e 4 The general developnent f o r w i n t e r f l ounde r from ha t ch ing t o a d u l t A newly hatched B 19 day l a r v a C l a r v a D j u v e n i l e ( h r t i n and Drewry 1978)

8

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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M a r t i n FD and GE Drewry 1978 Deve lopment of f i s h e s o f t h e Mid- A t l a n t i c B i g h t an a t l a s o f egg 1 a r v a l and juven i 1 e s tages Vol V I S t r o m a t e i d a e t h r o u g h Ogocepha l i d a e US F i s h W i l d l Serv B i o l Serv Program FWSOBS- 7812 416 pp

McCracken FD 1963 Seasonal movements o f the w in te r f lounder P s e u d o ~ l e u r o n e c t e s americanus (Walbaum) on the A t l a n t i c coast J Fish Res Board Can 20551-586

Morse W W 1981 Reproduc t i on o f t h e summer f l o u n d e r P a r a l i c h t h s d e n t a t u s ( L J d 19189-203

r i a t i o n a l Y a r i n e F i s h e r i e s S e r v i c e 1980 F i s h e r y S t a t i s t i c s o f t h e U n i t e d S t a t e s 1979 US N a t l Far F i s h Serv Cur r F i s h S t a t NO aooo

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987a F i s h e r i e s o f t h e U n i t e d S ta tes 1486 08 N a t l Mar F i s h Serv Cur r F i s h S t a t 8385

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987b Mar ine r e c r e a t i o n a l f i s h e r y s t a t i s t i c s survey A t l a n t i c and g u l f coas ts 1986 US N a t l Mar F i s h Serv Cur r F i s h S t a t 8392

O l l a BL R Wicklund and S Wilk 1969 Behavior o f winter f lounder i n a natura l h a b i t a t Trans Am Fish Soc 98717-720

O l l a BL CE Samet and AL Studholme 1972 A c t i v i t y and feeding behavior o f the summer flounder (Paral i c h t h v ~ dentatus) under c o n t r o l 1 ed 1 abora to ry conditions Fish B u l l 701127- 1136

P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

Tab1 e 1 Weigh t - l e n g t h r eg ress i ons f o r summer f l ounder where l o g we igh t ( g ) = a + b loglO l e n g t h (rnn) and r = c o r r e l a t i o n c o e f f i c i e n t (Ftogerloand Van Den Avy l e 1983)

L o c a t i o n and source a b r

Pamlico Sound Nor th Caro l ina (Powel 1 1974) -5254

Mid A t l a n t i c B i gh t (Wi 1 k e t a1 1978) Males -5289 Fernal es -5578

GROWTH CHARACTERISTICS

Growth Rates and Length- Weight Re1 a- t i o n s h i o s

I n t h e M i d - A t l a n t i c Region g rowth r a t e o f age I+ summer f l o u n d e r decreases f rom n o r t h t o south A s u b s t a n t i a l s h i f t i n s i z e a t age I from 26 mm i n New Je r sey t o 16 mm i n South Caro l i n a may r e s u l t f rom d i f f e r e n c e s i n g rowth r a t e s and spawning t imes peak spawning i n New Je r sey i s i n November w h i l e i t may occur as l a t e as March i n South C a r o l i n a (Smi th e t a l 1981) Growth o f young-o f - t he - yea r ceased toward t h e end o f t h e i r f i r s t yea r i n f a l l and d i d n o t resume aga in u n t i l s p r i n g when t h e f i s h were year1 i n g s (Powel l and Schwartz 1977) Tab le 1 shows t h e l e n g t h - w e i g h t r e 1 a t i o n s h i ps o f summer f l o u n d e r f o r Pam1 i c o Sound No r t h Ca ro l i na and t h e M i d - A t l a n t i c B i g h t (Rogers and Van Den Avy l e 1983)

P e a r c y ( 1962 ) pub1 i s h e d com- p r e h e n s i v e d a t a on growth r a t e s o f young-of- the-year w i n t e r f 1 ounder f rom t h e F l y s t i c R i v e r Es tua r y and noted seasona l changes i n growth Because metamorphosi s was no t completed u n t i l June growth d u r i n g t h e f i r s t 2 months was unde res t ima ted and was excluded f rom a n a l y s i s Growth o f o t o l i t h s a f t e r d e p o s i t i o n o f t h e opaque c e n t e r das v a r i a b l e consequent ly t h e age o f t h e y o u n g - o f - t h e - y e a r c a n n o t be

d e t e r m i n e d on t h e b a s i s o f o t o l i t h c h a r a c t e r i s t i c s Nean d a i l y growth r a t e s o f w i n t e r f l o u n d e r ( i n d r y we igh t ) were g rea te r a t 8 OC (101) than a t 5 OC (58) o r a t 2 OC (26) as shown b y Laurence (1975)

G r o w t h i n w e i g h t f o r w i n t e r f l o u n d e r was e s t i m a t e d b y Pea rcy ( 1 9 6 2 ) who t o o k ave rage l e n g t h of f l o u n d e r i n m i l l i m e t e r s a t t h e beg inn ing o f each month and conver ted i t t o weight i n grams by t h e formula ~ = 0 0 0 0 0 1 7 ~ ~ 3 ( F i g u r e 5 ) Females a re g e n e r a l l y 1 a r g e r than males o f t h e

AVERAGE WEIGHT L -2 2

w 40- I

0 3- 2

6 C V)

-4 $ S I

GROWTH RATE - - -

n 3

I rn

--

JJASONDJFMAMJJASONDJF

F igu re 5 Average month ly weight g a i n f o r w i n t e r f l o u n d e r i n t h e M y s t i c R i v e r es tua r y (Pearcy 1962)

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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Morse W W 1981 Reproduc t i on o f t h e summer f l o u n d e r P a r a l i c h t h s d e n t a t u s ( L J d 19189-203

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P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

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a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

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~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

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R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

Tab le 2 Es t ima ted l e n g t h (mm TL) a t age f o r w i n t e r f l o u n d e r s o u t h o f Cape Cod o f f Massachuset ts (Howe and Coates 1975)

Length (mm TI-) Age Ma1 es Females

111 I I v v I V I I V I I I I X X X I X I I

s a m e a g e ( T a b l e 2 ) a n d g r o w s i g n i f i c a n t l y f a s t e r (Howe and Coates 1975)

THE FISHERY

Commerci a1 F i s h e r i e s -

I n t h e l a t e 19201s as t r a w l e r s f r o m n o r t h e r n p o r t s moved s o u t h t o e x p l o i t f l o u n d e r s and o t h e r spec ies t h e Cape H a t t e r a s w i n t e r t r a w l f i s h e r y was i n i t i a t e d (Pearson 1932)

The average t o t a l annual 1 andings f o r 1974 t h r o u g h 1978 i n N o r t h C a r o l i n a were about 84 m i l l i o n kg v a l u e d a t $9 7 m i l l i o n ( i i a t i o n a l Mar ine F i s h e r i e s S e r v i c e 1980)

Edwards (1968) computed biomass o f w i n t e r f l o u n d e r on t h e C o n t i n e n t a S h e l f o f New England b y c a l c u l a t i n g t h e average c a t c h i n pounds pe r tow made b y t h e 1963-66 g r o u n d f i s h su rvey u s i n g a 36 Yankee t r a w l (0 5 i n c h c o d e n d l i n e r ) B i o m a s s w a s c a l c u l a ted b y mu1 t i p l y i n g c a t c h p e r tow b y a c o r r e c t i o n f a c t o r wh ich was t h e number o f square m i l e s f o r each zone d i v i d e d b y t h e a rea swept b y t h e

n e t i n each tow A f t e r t h e use of a second c o r r e c t i o n f a c t o r t h a t e l i m i - na ted r e m a i n i n g b i ases s t a n d i n g c r o p f o r i n s h o r e wa te rs o f New England was es t ima ted a t 90 mi 11 i o n pounds O f f sou theas te rn Massachusetts t h e w i n t e r f l o u n d e r s u p p o r t s a c o a s t a l g round f i s h e r y i n s p r i n g and autumn and an o f f s h o r e f i s h e r y i n summer (Howe e t a1 1976) I n a nea rby area f i s h i n g p r e s s u r e was n o t c o r r e l a t e d w i t h dep ress ion i n abundance o f t h e i n s h o r e spawning s t o c k ( J e f f r i es and Johnson 1974)

Smolowi t z (1983) demonstrated t h a t when used t o catch w i n t e r founder t r a w l nets w i t h an average mesh s i z e o f 133 mm i n the cod end ( l a r g e mesh) decreased weight o f discarded f i s h by 73 compared t o nets averaging 103 mm i n the cod end (small mesh)

R e c r e a t i o n a l F i s h e r i e s

Compared t o ca tches i n t h e Mid- At1 a n t i c B i g h t t h e r e c r e a t i o n a l c a t c h o f summer f l o u n d e r i n t h e S o u t h A t l a n t i c B i g h t i s m i n o r I n t h e South A t l a n t i c S i g h t N o r t h C a r o l i n a f i she rmen t a k e 72 o f t h e t o t a l c a t c h F i s h l e s s t h a n f i v e y e a r s o l d make up most o f r e c r e a t i o n a l c a t c h i n t h e Mid- A t l a n t i c B i g h t

B r i g g s ( 1 9 6 5 ) who c a l c u l a t e d c a t c h r a t e o f w i n t e r f l o u n d e r pe r u n i t o f e f f o r t (16-20 f i sh ang l e r t r i p ) b y sportsmen f i s h i n g f r o m f i v e t ypes o f b o a t s i n f o u r l o c a t i o n s arouno Long I s l a n d f o r e a c h m o n t h i n 1961-b3 s h o w e d t h a t c a t c h was h i g h e s t i n s p r i n g and lowes t i n summer

P o p u l a t i o n Dynamics

I d e n t i f i c a t i o n o f t h e summer and w i n t e r f l o u n d e r s t o c k s and s t o c k - s p e c i f i c b i o l o g i c a l t r a i t s i s necessa ry f o r p r o p e r management s i n c e g e n e t i c a l l y d i s t i n c t s t o c k s can have d i f f e r e n t r a t e s o f r e c r u i t m e n t growth and m o r t a l i t y The e x i s t e n c e o f t h r e e s p a w n i n g p o p u l a t i o n s was

p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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p r o p o s e d b y Srni t h (1973) (one each f r o m Cape Cod t o D e l a w a r e Bay V i r g i n i a t o Cape H a t t e r a s N o r t h C a r o l i n a C a p e H a t t e r a s t o Cape Lookout North Carol ina) W i l k e t a1 (1980) used d i sc r im inan t ana lys is o f morphometric characters t o conclude t h a t summer f lounder from the Mid- A t l a n t i c and South A t l a n t i c Bights c o n s t i t u t e two separate stocks d i v ided by Cape Hatteras The d i s t r i b u t i o n o f j uven i l es i n Paml i c o Sound i s ubiqui tous and the estuary i s accessib le t o both stocks Juveni les i n Paml i c o Sound may e x i t t o j o i n the stock o f f sho re t o which they belong

Pierce and Howe (1977) suggest on the bas is o f f i n r a y counts t h a t w in te r f lounder south o f Cape Cod ( i n c l uding Marthas Vineyard but no t Buzzards Bay) be managed as a u n i t stock Sai 1 a (1962a b) who compared sex r a t i o s o f w i n t e r f lounder i n Narragansett Bay Rhode I s 1 and w i t h those from Char1 estown Pond Rhode Is land concluded t h a t t he h igher p ropor t i on o f females than males i n the catch was due t o catch s e l e c t i v i t y f o r l a r g e r f i s h females are considerably 1 arger than males and the market preference i s f o r l a r g e r f i s h

ECOLOGICAL ROLE

Food H a b i t s

I t h a s b e e n s u g g e s t e d t h a t zoop l ankton and s m a l l c rus taceans a r e e a t e n b y l a r v a l and pos t1 a r v a l summer f 1 o u n d e r b u t s u p p o r t i n g d a t a i s l a c k i n g Mys id shr imp and sma l l f i s h a r e t h e d i e t o f j u v e n i l e s and a d u l t s f e e d on f i s h and n y s i d and decapod c rus taceans ( H i 1 debrand and Schroeder 1928 Smi th and Da ibe r 1977 Powe l l and Schwartz 1979)

S u l l i v a n ( 1 9 1 4 ) s t a t e d t h a t w i n t e r f l o u n d e r 1 a rvae d i d n o t e a t u n t i l a f t e r y o l k a b s o r p t i o n Pearcy (1962) p r e s e n t s a d e t a i l e d account o f l a r v a l and y o u n g j u v e n i l e f e e d i n g

h a b i t s T h r o u g h o u t t h e i r r a n g e a d u l t s m a i n t a i n e d a v a r i e d d i e t f rom po lychae tes t o f i s h eggs T h e i r d i e t i s r e l a t e d t o s i z e t h e l a r g e r t h e i n d i v i d u a l t h e g r e a t e r t h e s i z e of t h e f o o d i t e m t o be consumed The ~ n a j o r f o o d t y p e s o f w i n t e r f l o u n d e r were p o l y c h a e t e s and amphi pods f o r f i s h 1 1 - 2 6 cm l o n g f r o m A p r i l t o October (Worobec 1984) Predominant s i z e s o f i n v e r t e b r a t e s e a t e n w e r e s i m i l a r t o p redominan t s i z e s i n t h e h a b i t a t f o r w i n t e r f l o u n d e r 25-29 cm l o n g b u t f i s h 3 0 - 3 5 cm l o n g s e l e c t i v e l y chose 1 a r g e r p r e y ( L e v i n g s 1974) W in te r f l o u n d e r i n Canada d i d n o t f e e d u n t i l a f t e r spawning a t t h e s t a r t o f t h e seaward m i g r a t i o n when t h e y began f e e d i q g on po l ychae tes and 1 arge amphi pods ( J e f f r i e s and Johnson 1974)

Feed ing Behav io r

Adu l t summer f lounder feed i n es tuar ies and s h e l f waters and are more a c t i v e du r ing d a y l i g h t hours (01 1 a e t a1 1972 Smith and Dai ber 1977) Summer f lounder can feed equa l l y we1 1 i n t h e water column o r on the bottom Bottom feeding i s always preceded by an a c t i v e search and benth ic prey i s u s u a l l y sta lked Searching s ta l k ing a c t i v e eye motion and v i sua l f i x a t i o n on prey dur ing the day i n d i c a t e t h a t summer f lounder are p r i m a r i l y v i sua l feeders then (01 1 a e t a1 1972)

Winter f lounder feed p a r t l y by s igh t They l i e s t i l l on t h e bottom j u s t before l ung ing a t prey They are i n a c t i v e from w i t h i n 30 minutes a f t e r evening t w i l i g h t u n t i l the beginning o f morning t w i l i g h t F ish feed throughout t h e day (01 1 a e t a1 1969)

P a r a s i t e s

T h e m i c r o s p o r i d e a n p r o t o z o a n Glugea s t e p h a n i i n f e c t e d 8 o f w i n t e r f l o u n d e r sampled f r o m t h e M i d - A t l a n t i c Region t h e i n f e c t i o n i s p r e s e n t yea r - round ( T a k v o r i a n and C a l i 1984)

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

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Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

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Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

ENVIRONMENTAL REQU IREPIENTS

Temperature and S a l i n i t y

A l though t h e summer f l o u n d e r i s t o l e r a n t o f a w ide range o f chemica l and p h y s i c a l c o n d i t i o n s such f a c t o r s do i n f l u e n c e i t s b i o l o g y A the rma l shock ( t e m p e r a t u r e i n c r e a s e ) o f 20 OC

above an a c c i i m a t i o n t e m p e r a t u r e o f a b o u t 15 O C caused no m o r t a l i t y i n e a r l y embryo s t a g e eggs o f summer f l o u n d e r b u t a shock o f 16 OC f o r 16 m i n u t e s o r 18 OC f o r 2 m inu tes caused m o r t a l i t y i n l a t e embryo s t a g e eqgs ( I t z k o w i t z e t a l 1983) F o i l o w i n g a t h e r m a l s h o c k o f 1 0 O C above an a c c l i m a t i o n t e m p e r a t u r e o f 15 O C

1 arvae were a c t u a l l y l e s s s u s c e p t i b l e t o p r e d a t i o n t h a n c o n t r o l l a r v a e ( D e a c u t i s 1978) I n t h e Mid-At1 a n t i c G i g k t n o r t h o f C h e s a p e a k e B a y s p a w n i n g and t h e o f f s h o r e l i m i t s o f m i g r a t i o n c o i n c i d e w i t h t h e i n s h o r e edge o f t h e mass o f c o l d bo t tom wa te r w h i c h d i s a p p e a r s a l o n g w i t h t h e the rmoc l i ne i n November ( S m i t h 1973) Growth e f f i c i e n c y f e e d i n g r a t e and a s s i m i l a t i o n e f f i c i e n c y o f j u v e n i l e s i s d i r e c t l y r e l a t e d t o t e m p e r a t u r e u n d e r 1 a b o r a t o r y c o n d i t i o n s ( P e t e r s and A n g e l o v i c 1971) Growth r a t e and g r o w t h e f f i c i e n c y a r e g r e a t e s t a t s a l i n i t i e s gt l 0 p p t Summer f l o u n d e r were found a t s a l i n i t i e s o f 12-35 p p t i n Pam1 i c o Sound ove r sand o r sandy mud r a t h e r t h a n s i l t o r c l a y (Powe l l and Schwartz 1977) Paml i co Sound i s u n u s u a l however because t i d e s a r e m i n o r a n d s a l i n i t i e s a r e u n i f o r m t h r o u g h o u t much o f t h e sound I n e s t u a r i e s w i t h m a j o r t i d e s t h a t a f f e c t t h e h o r i z o n t a l s a l i n i t y g r a d i e n t o r e s t u a r i e s w i t h d i f f e r e n t s u b s t r a t e t y p e - s a l i n i t y r e 1 a t i o n s h i p s t h e d i s t r i b u t i o n o f summer f l o u n d e r m i g h t b e d i f f e r e n t ( P o w e l l and S c h w a r t z 1977)

V i a b l e h a t c h i n g o f w i n t e r f l o u n d e r eggs was o p t i m a l a t 3 OC and 1 5 - 2 5 p p t ( R o g e r s 1976) Y e a r l i n g w i n t e r f l o u n d e r p r e f e r a tempera tu re o f 18 5 O C ( C a s t e r l i n and Reynolds 1 9 8 2 ) A f t e r a c c l i m a t i o n a t 5 OC

w in te r f lounder 1 arvae suf fe red low

m o r t a l i t y dur ing 4-64 minutes o f exposure t o a thermal shock o f 22 C ( I t z k o w i t z and Schubel 1983) Thermal shocks o f 28-30 C f o r 4 minutes produced 100 morta l i t y Larvae ent ra ined i n the cool i n g water systems o f power p l a n t s encounter thermal shocks o f 5-23 C ( I t z k o w i t z and Schubel 1983) Winter f lounder (about 10 cm long) had an upper i n c i p i e n t l e t h a l temperature ( a f t e r 48 hours) o f about 29 C a f t e r acc l imat ion a t e i t h e r 28 C o r 22 C (Hof f and Westman 1966) Upper i n c i p i e n t l e t h a l temperatures were 19 C a f t e r acc l imat ion a t 4 C and 265 C a f t e r acc l imat ion a t 20 C (McCracken 1963) Winter f lounder become i n a c t i v e above 222 C (01 1 a e t a1 1969)

L o w e r i n c i p i e n t l e t h a l temperatures ( f o r 48 h r exposures) a f t e r acc l imat ion a t 28 C and 21 C were ( respec t i ve l y ) 54 C and 10 C (Hof f and Westman 1966) I n a seven year study t he w in te r f lounder ca tch was nega t i ve l y co r re la ted w i t h degree- days (an est imate r e l a t e d t o average temperature) over the previous 30 months ( J e f f r i e s and Johnson 1974) A s l i g h t increase i n average temperature ( lt 0 5 OC) may h i n d e r r e c r u i t m e n t t o t h e f i s h e r y p r o b a b l y t h r o u g h i n d i r e c t e f f e c t s on t h e ecosystem ( J e f f r i e s and Johnson 1974)

P o l l u t i o n

I n w i n t e r f l o u n d e r f i n r o t d i s e a s e o c c u r r e d more f r e q u e n t l y i n a p o l l u t e d a r e a ( i n c i d e n c e = 14-16) t h a n i n u n p o l l u t e d w a t e r s (3) i n t h e M i d - A t l a n t i c R e g i o n ( Z i s k o w s k i and Murchel ano 1975) F i n r o t preval ence was r e l a t i v e l y low i n southern New England ten o f f sho re waters o f t he New York Bight and on Georges Bank compared t o prevalence i n the Gu l f o f Maine Lymphocystis (a v i r a l disease) was most common i n o f f sho re waters between Delaware Bay and Massachusetts (Ziskowski e t a l 1987) I n the 1 aboratory m o r t a l i t y i n the summer was s i g n i f i c a n t l y increased i n w in te r

f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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f lounder exposed t o o i l e d sediments Feeding ra tes were s i g n i f i c a n t l y less i n f i s h exposed t o f resh o i l i n sediments but 1 i t t l e o r no response t o o i l e d sediments aged f o r 1 year was observed Reduced feeding i n response t o o i 1 contamination could deplete reserves t h a t w in ter f lounder need f o r sustenance and reproduct ion i n w in ter (F le tcher e t a1 1981) No feeding o r m o r t a l i t y occurred i n w in ter

Summer f l o u n d e r 1 arvae s u r v i v e d exposu re t o h i g h c o n c n t r a t i o n s o f sea w a t e r sed iment e x t r a c t f r o m Char1 e s t o n H a r b o r 5 o u t h C a r o l i na b e t t e r t h a n d i d p i n f i s h 1 arvae s u r v i v a l was 100

( H o s s e t a l 1 9 7 4 ) The sed iment e x t r a c t p r o b a b l y c o n t a i n e d a n y c o n t a m i n a n t s t h a t w o u l d b e i n t h e o u t f a l l ( r u n o f f ) f rom a dyked d i s o o s a l a rea f o r dredged m a t e r i a l t a k e n f r o m the harbor (Hoss e t a l 1974) F in r o t disease i n summer f lounder was s l i g h t l y more common i n the inshore waters o f the New York and New Jersey coasts than i n more o f fshore waters (Ziskowski e t a l 1987) I n a model o f the e f f e c t s o f p o l l u t i o n on a mu1 t i species group o f coastal f ishes summer f l ounder showed moderate e f fec ts (depression o f abundance) bu t took 10-12 years t o recover (Schaaf e t a1 1987)

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B i g e l ow HB and W C Schroeder 1953 F i s h e s o f t h e G u l f o f Vlaine US F i s h k i l d l Serv F i s h B u l l 53 577 pp

Breder CM J r 1922 D e s c r i p t i o n o f t h e s p a w n i n g h a b i t s o f P s e u d o p l e u r o n e c t e s a m e r i c a n u s i n c a p t i v i t y Copeia 1023-4

B r e d e r C M J r 1 9 2 4 Some embryonic and l a r v a l s tages o f t h e w i n t e r f l o u n d e r B u l l US Bur F i s h 38311-315

B r i g g s P T 1 3 6 5 T h e s o o r t f i s h e r i e s f c r w i n t e r f l o u n d e r i n s e v e r a l bays o f Long I s l a n d N Y F i s h Game J 1248-70

Burton MP and D R I d l e r 1984 The reproductive cycle i n winter f lounder ~l euronectes - Can J Zool 622563-2567

C a s t e r 1 i n FIE and W W Reyno lds 1982 Thermoregul a t o r y b e h a v i o r and d i e 1 a c t i v i t y o f y e a r l i n g w i n t e r f l o u n d e r ~ s e u d ~ ~ l e u r o n e c t e s americanus Env i ron B i o l F ishes 7177-180

D e a c u t i s CF 1978 E f f e c t o f thermal shock on p r e d a t o r avo idance b y l a r v a e o f two f i s h s p e c i e s Trans Am F i s h Soc 107632-635

D i c k i e LM and FD McCracken 1955 I s o p l e t h d iagrams t o p r e d i c t e q u i l i b r i u m y i e l d s o f a s m a l l f l o u n d e r f i s h e r y J F i s h Res Board Can 12 187-209

Deubler EE J r 1958 A comparative study o f the post larvae o f three flounders (Para1 ichthvs) i n North Carol ina Copeia 1958 112- 116

E d w a r d s R L 1 9 6 8 F i s h e r y r e s o u r c e s o f t h e N o r t h A t l a n t i c area Pages 52-60 i n D G i l b e r t ed The f u t u r e o f t h e f i s h i n g i n d u s t r y o f U n i t e d S t a t e s Un iv Wash Pub l F i s h New Ser 4

Fletcher G L J W Kiceni uk and V P Will iams 1981 E f fec ts o f o i l e d sediments on mor ta l i t y feeding and growth o f w i n t e r f l o u n d e r (Pseudo~ l euronectes americanus) Mar Ecol Prog Ser 491-96

H i 1 debrand S F and WC Schroeder 1928 F i s h e s o f t h e Chesapeake Bay US B u r e a u o f F i s h e r i e s 1024366 PP

H o f f JG and JR Westman 1966 The tempera tu re t o l e r a n c e s o f t h r e e spec ies o f m a r i n e f i s h e s J Mar Res 24131-140

Hoss DE LC C o s t o n and WE Schaaf 1974 E f f e c t s o f seawater e x t r a c t s o f s e d i m e n t s f r o m C h a r l e s t o n Harbor SC on l a r v a l e s t u a r i n e f i s h e s E s t u a r i n e Coas ta l Fiar S c i 2 323-328

Howe AB and PG Coates 1975 W i n t e r f l o u n d e r movements growth and m o r t a l i t y o f f P l a s s a c h u s e t t s Trans Am F i s h Soc 10413-29

Howe AB PG C o a t e s and DE P i e r c e 1976 W i n t e r f l o u n d e r

e s t u a r i n e y e a r - c l ass abundance m o r t a l i t y and r e c r u i t m e n t Trans Am F i s h Soc 105647-657

I t z k o w i t z N and JR S c h u b e l 1983 To1 e r a n c e o f f i v e - d a y - o l d w i n t e r f l o u n d e r pseudopl eu ronec tes americanus 1 arvae t o thermal shock US N a t l Mar F i s h Serv F i s h B u l l 81913-916

I t z k o w i t z N JR S c h u b e l and PMJ Woodhead 1983 R e s ~ o n s e s o f summer f l o u n d e r P a r a l i k h t h y s den ta tus embryos t o thermal shock Env i ron B i o l F i s h e s 8125-135

J e f f r i e s HP and W C Johnson 1974 S e a s o n a l d i s t r i b u t i o n s o f b o t t o m f i s h e s i n t h e N a r r a g a n s e t t 3ay area seven-year v a r i a t i o n s n t h e a ~ u n d a n c e o f w i n t e r f l o u n d e r (Pseudopl eu ronec tes americanus) J F i s h Res 3oard Can 311057- i066

J o h n s I WH H o w e l l and S K l e i n - F a c P h e e 1 9 8 1 Y o l k u t i l i z a t i o n and g rowth t o y o l k sac a b s o r p t i o n i n summer f l o u n d e r ( P a r a l i c h t h y s d e n t a t u s ) l a r v a e a t c o n s t a n t and c y c l i c tempera tu res K a r B i o l ( B e r l ) 63301-330

Kennedy VS and 3H S t e e l e 1971 T h e w i n t e r f l o u n d e r ( P s e u d o p l eu ronec tes americanus) i n L o n g P o n d C o n c e p t i o n B a y Wewfoundl and J F i s h Res Board Can 281153-1165

Keup L and J aay less 1964 F i s h d i s t r i b u t i o n a t v a r y i n g s a l i n i t i e s i n N e u s e R i v e r b a s i n N o r t h Caro l i n a Chesapeake S c i 5119- 123

L a u r e n c e G C 1975 L a b o r a t o r y g r o w t h and me tabo l i sm o f t h e w i n t e r f 1 o u n d e r P s e u d o p l e u r o n e c t e s a m e r i c a n u s f r o m h a t c h i n g t h r o u g h metamorphosis a t t h r e e tempera tu res Mar B i o l ( B e r l ) 32223-229

Lev ings CD 1974 Seasonal changes i n f e e d i n g and p a r t i c l e s e l e c t i o n b y

w i n t e r f l o u n d e r (Pseudopl eu ronec tes amer icanus) Trans Am F i s h Soc 103828-832

M a r t i n FD and GE Drewry 1978 Deve lopment of f i s h e s o f t h e Mid- A t l a n t i c B i g h t an a t l a s o f egg 1 a r v a l and juven i 1 e s tages Vol V I S t r o m a t e i d a e t h r o u g h Ogocepha l i d a e US F i s h W i l d l Serv B i o l Serv Program FWSOBS- 7812 416 pp

McCracken FD 1963 Seasonal movements o f the w in te r f lounder P s e u d o ~ l e u r o n e c t e s americanus (Walbaum) on the A t l a n t i c coast J Fish Res Board Can 20551-586

Morse W W 1981 Reproduc t i on o f t h e summer f l o u n d e r P a r a l i c h t h s d e n t a t u s ( L J d 19189-203

r i a t i o n a l Y a r i n e F i s h e r i e s S e r v i c e 1980 F i s h e r y S t a t i s t i c s o f t h e U n i t e d S t a t e s 1979 US N a t l Far F i s h Serv Cur r F i s h S t a t NO aooo

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987a F i s h e r i e s o f t h e U n i t e d S ta tes 1486 08 N a t l Mar F i s h Serv Cur r F i s h S t a t 8385

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987b Mar ine r e c r e a t i o n a l f i s h e r y s t a t i s t i c s survey A t l a n t i c and g u l f coas ts 1986 US N a t l Mar F i s h Serv Cur r F i s h S t a t 8392

O l l a BL R Wicklund and S Wilk 1969 Behavior o f winter f lounder i n a natura l h a b i t a t Trans Am Fish Soc 98717-720

O l l a BL CE Samet and AL Studholme 1972 A c t i v i t y and feeding behavior o f the summer flounder (Paral i c h t h v ~ dentatus) under c o n t r o l 1 ed 1 abora to ry conditions Fish B u l l 701127- 1136

P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

LITERATNE CITED

B i g e l ow HB and W C Schroeder 1953 F i s h e s o f t h e G u l f o f Vlaine US F i s h k i l d l Serv F i s h B u l l 53 577 pp

Breder CM J r 1922 D e s c r i p t i o n o f t h e s p a w n i n g h a b i t s o f P s e u d o p l e u r o n e c t e s a m e r i c a n u s i n c a p t i v i t y Copeia 1023-4

B r e d e r C M J r 1 9 2 4 Some embryonic and l a r v a l s tages o f t h e w i n t e r f l o u n d e r B u l l US Bur F i s h 38311-315

B r i g g s P T 1 3 6 5 T h e s o o r t f i s h e r i e s f c r w i n t e r f l o u n d e r i n s e v e r a l bays o f Long I s l a n d N Y F i s h Game J 1248-70

Burton MP and D R I d l e r 1984 The reproductive cycle i n winter f lounder ~l euronectes - Can J Zool 622563-2567

C a s t e r 1 i n FIE and W W Reyno lds 1982 Thermoregul a t o r y b e h a v i o r and d i e 1 a c t i v i t y o f y e a r l i n g w i n t e r f l o u n d e r ~ s e u d ~ ~ l e u r o n e c t e s americanus Env i ron B i o l F ishes 7177-180

D e a c u t i s CF 1978 E f f e c t o f thermal shock on p r e d a t o r avo idance b y l a r v a e o f two f i s h s p e c i e s Trans Am F i s h Soc 107632-635

D i c k i e LM and FD McCracken 1955 I s o p l e t h d iagrams t o p r e d i c t e q u i l i b r i u m y i e l d s o f a s m a l l f l o u n d e r f i s h e r y J F i s h Res Board Can 12 187-209

Deubler EE J r 1958 A comparative study o f the post larvae o f three flounders (Para1 ichthvs) i n North Carol ina Copeia 1958 112- 116

E d w a r d s R L 1 9 6 8 F i s h e r y r e s o u r c e s o f t h e N o r t h A t l a n t i c area Pages 52-60 i n D G i l b e r t ed The f u t u r e o f t h e f i s h i n g i n d u s t r y o f U n i t e d S t a t e s Un iv Wash Pub l F i s h New Ser 4

Fletcher G L J W Kiceni uk and V P Will iams 1981 E f fec ts o f o i l e d sediments on mor ta l i t y feeding and growth o f w i n t e r f l o u n d e r (Pseudo~ l euronectes americanus) Mar Ecol Prog Ser 491-96

H i 1 debrand S F and WC Schroeder 1928 F i s h e s o f t h e Chesapeake Bay US B u r e a u o f F i s h e r i e s 1024366 PP

H o f f JG and JR Westman 1966 The tempera tu re t o l e r a n c e s o f t h r e e spec ies o f m a r i n e f i s h e s J Mar Res 24131-140

Hoss DE LC C o s t o n and WE Schaaf 1974 E f f e c t s o f seawater e x t r a c t s o f s e d i m e n t s f r o m C h a r l e s t o n Harbor SC on l a r v a l e s t u a r i n e f i s h e s E s t u a r i n e Coas ta l Fiar S c i 2 323-328

Howe AB and PG Coates 1975 W i n t e r f l o u n d e r movements growth and m o r t a l i t y o f f P l a s s a c h u s e t t s Trans Am F i s h Soc 10413-29

Howe AB PG C o a t e s and DE P i e r c e 1976 W i n t e r f l o u n d e r

e s t u a r i n e y e a r - c l ass abundance m o r t a l i t y and r e c r u i t m e n t Trans Am F i s h Soc 105647-657

I t z k o w i t z N and JR S c h u b e l 1983 To1 e r a n c e o f f i v e - d a y - o l d w i n t e r f l o u n d e r pseudopl eu ronec tes americanus 1 arvae t o thermal shock US N a t l Mar F i s h Serv F i s h B u l l 81913-916

I t z k o w i t z N JR S c h u b e l and PMJ Woodhead 1983 R e s ~ o n s e s o f summer f l o u n d e r P a r a l i k h t h y s den ta tus embryos t o thermal shock Env i ron B i o l F i s h e s 8125-135

J e f f r i e s HP and W C Johnson 1974 S e a s o n a l d i s t r i b u t i o n s o f b o t t o m f i s h e s i n t h e N a r r a g a n s e t t 3ay area seven-year v a r i a t i o n s n t h e a ~ u n d a n c e o f w i n t e r f l o u n d e r (Pseudopl eu ronec tes americanus) J F i s h Res 3oard Can 311057- i066

J o h n s I WH H o w e l l and S K l e i n - F a c P h e e 1 9 8 1 Y o l k u t i l i z a t i o n and g rowth t o y o l k sac a b s o r p t i o n i n summer f l o u n d e r ( P a r a l i c h t h y s d e n t a t u s ) l a r v a e a t c o n s t a n t and c y c l i c tempera tu res K a r B i o l ( B e r l ) 63301-330

Kennedy VS and 3H S t e e l e 1971 T h e w i n t e r f l o u n d e r ( P s e u d o p l eu ronec tes americanus) i n L o n g P o n d C o n c e p t i o n B a y Wewfoundl and J F i s h Res Board Can 281153-1165

Keup L and J aay less 1964 F i s h d i s t r i b u t i o n a t v a r y i n g s a l i n i t i e s i n N e u s e R i v e r b a s i n N o r t h Caro l i n a Chesapeake S c i 5119- 123

L a u r e n c e G C 1975 L a b o r a t o r y g r o w t h and me tabo l i sm o f t h e w i n t e r f 1 o u n d e r P s e u d o p l e u r o n e c t e s a m e r i c a n u s f r o m h a t c h i n g t h r o u g h metamorphosis a t t h r e e tempera tu res Mar B i o l ( B e r l ) 32223-229

Lev ings CD 1974 Seasonal changes i n f e e d i n g and p a r t i c l e s e l e c t i o n b y

w i n t e r f l o u n d e r (Pseudopl eu ronec tes amer icanus) Trans Am F i s h Soc 103828-832

M a r t i n FD and GE Drewry 1978 Deve lopment of f i s h e s o f t h e Mid- A t l a n t i c B i g h t an a t l a s o f egg 1 a r v a l and juven i 1 e s tages Vol V I S t r o m a t e i d a e t h r o u g h Ogocepha l i d a e US F i s h W i l d l Serv B i o l Serv Program FWSOBS- 7812 416 pp

McCracken FD 1963 Seasonal movements o f the w in te r f lounder P s e u d o ~ l e u r o n e c t e s americanus (Walbaum) on the A t l a n t i c coast J Fish Res Board Can 20551-586

Morse W W 1981 Reproduc t i on o f t h e summer f l o u n d e r P a r a l i c h t h s d e n t a t u s ( L J d 19189-203

r i a t i o n a l Y a r i n e F i s h e r i e s S e r v i c e 1980 F i s h e r y S t a t i s t i c s o f t h e U n i t e d S t a t e s 1979 US N a t l Far F i s h Serv Cur r F i s h S t a t NO aooo

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987a F i s h e r i e s o f t h e U n i t e d S ta tes 1486 08 N a t l Mar F i s h Serv Cur r F i s h S t a t 8385

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987b Mar ine r e c r e a t i o n a l f i s h e r y s t a t i s t i c s survey A t l a n t i c and g u l f coas ts 1986 US N a t l Mar F i s h Serv Cur r F i s h S t a t 8392

O l l a BL R Wicklund and S Wilk 1969 Behavior o f winter f lounder i n a natura l h a b i t a t Trans Am Fish Soc 98717-720

O l l a BL CE Samet and AL Studholme 1972 A c t i v i t y and feeding behavior o f the summer flounder (Paral i c h t h v ~ dentatus) under c o n t r o l 1 ed 1 abora to ry conditions Fish B u l l 701127- 1136

P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

e s t u a r i n e y e a r - c l ass abundance m o r t a l i t y and r e c r u i t m e n t Trans Am F i s h Soc 105647-657

I t z k o w i t z N and JR S c h u b e l 1983 To1 e r a n c e o f f i v e - d a y - o l d w i n t e r f l o u n d e r pseudopl eu ronec tes americanus 1 arvae t o thermal shock US N a t l Mar F i s h Serv F i s h B u l l 81913-916

I t z k o w i t z N JR S c h u b e l and PMJ Woodhead 1983 R e s ~ o n s e s o f summer f l o u n d e r P a r a l i k h t h y s den ta tus embryos t o thermal shock Env i ron B i o l F i s h e s 8125-135

J e f f r i e s HP and W C Johnson 1974 S e a s o n a l d i s t r i b u t i o n s o f b o t t o m f i s h e s i n t h e N a r r a g a n s e t t 3ay area seven-year v a r i a t i o n s n t h e a ~ u n d a n c e o f w i n t e r f l o u n d e r (Pseudopl eu ronec tes americanus) J F i s h Res 3oard Can 311057- i066

J o h n s I WH H o w e l l and S K l e i n - F a c P h e e 1 9 8 1 Y o l k u t i l i z a t i o n and g rowth t o y o l k sac a b s o r p t i o n i n summer f l o u n d e r ( P a r a l i c h t h y s d e n t a t u s ) l a r v a e a t c o n s t a n t and c y c l i c tempera tu res K a r B i o l ( B e r l ) 63301-330

Kennedy VS and 3H S t e e l e 1971 T h e w i n t e r f l o u n d e r ( P s e u d o p l eu ronec tes americanus) i n L o n g P o n d C o n c e p t i o n B a y Wewfoundl and J F i s h Res Board Can 281153-1165

Keup L and J aay less 1964 F i s h d i s t r i b u t i o n a t v a r y i n g s a l i n i t i e s i n N e u s e R i v e r b a s i n N o r t h Caro l i n a Chesapeake S c i 5119- 123

L a u r e n c e G C 1975 L a b o r a t o r y g r o w t h and me tabo l i sm o f t h e w i n t e r f 1 o u n d e r P s e u d o p l e u r o n e c t e s a m e r i c a n u s f r o m h a t c h i n g t h r o u g h metamorphosis a t t h r e e tempera tu res Mar B i o l ( B e r l ) 32223-229

Lev ings CD 1974 Seasonal changes i n f e e d i n g and p a r t i c l e s e l e c t i o n b y

w i n t e r f l o u n d e r (Pseudopl eu ronec tes amer icanus) Trans Am F i s h Soc 103828-832

M a r t i n FD and GE Drewry 1978 Deve lopment of f i s h e s o f t h e Mid- A t l a n t i c B i g h t an a t l a s o f egg 1 a r v a l and juven i 1 e s tages Vol V I S t r o m a t e i d a e t h r o u g h Ogocepha l i d a e US F i s h W i l d l Serv B i o l Serv Program FWSOBS- 7812 416 pp

McCracken FD 1963 Seasonal movements o f the w in te r f lounder P s e u d o ~ l e u r o n e c t e s americanus (Walbaum) on the A t l a n t i c coast J Fish Res Board Can 20551-586

Morse W W 1981 Reproduc t i on o f t h e summer f l o u n d e r P a r a l i c h t h s d e n t a t u s ( L J d 19189-203

r i a t i o n a l Y a r i n e F i s h e r i e s S e r v i c e 1980 F i s h e r y S t a t i s t i c s o f t h e U n i t e d S t a t e s 1979 US N a t l Far F i s h Serv Cur r F i s h S t a t NO aooo

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987a F i s h e r i e s o f t h e U n i t e d S ta tes 1486 08 N a t l Mar F i s h Serv Cur r F i s h S t a t 8385

N a t i o n a l M a r i n e F i s h e r i e s S e r v i c e 1987b Mar ine r e c r e a t i o n a l f i s h e r y s t a t i s t i c s survey A t l a n t i c and g u l f coas ts 1986 US N a t l Mar F i s h Serv Cur r F i s h S t a t 8392

O l l a BL R Wicklund and S Wilk 1969 Behavior o f winter f lounder i n a natura l h a b i t a t Trans Am Fish Soc 98717-720

O l l a BL CE Samet and AL Studholme 1972 A c t i v i t y and feeding behavior o f the summer flounder (Paral i c h t h v ~ dentatus) under c o n t r o l 1 ed 1 abora to ry conditions Fish B u l l 701127- 1136

P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

P e a r c y kG 1962 Eco logy o f an e s t u a r i n e p o p u l a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l ~ u r o n e c t e s americanus (Na l ~au rn ) Y u l l oingnam C I c e a n o s r C o l l e c t Y a l e U n i v

P e a r s o n JC 1932 W i n t e r t r a w l f i s h e r y o f f t h e V i r g i n i a and N o r t h C a r o l i n a c o a s t s 1JS Eur F i s h I n v e s t Rep 10 3 1 pp

P e t e r s D S a n d JW A n g e l o v i c 1 9 7 1 E f f e c t o f t e m p e r a t u r e s a l i n i t y and f o o d a v a i l a b i l i t y on g r o w t h and e n e r g y u t i l i z a t i o n o f i u v e n i 1 e s a m m e r f l o u n d e r pa ra1 i c h t h y s d e n t a t u s Pages 5451 5 5 4 i n D J N e l s o n e d ~ a d i o c c l i d e s i n e c o s y s t e m s Wat iona l Symposium on Rad ioeco logy Oak Ridge Tenn

Pierce DE and AB Howe 1977 A further study on winter flounder g r o u p i d e n t i f i c a t i o n o f f Massachusetts Trans Am Fish SOC 106131-139

Powe l l AB 1974 B i o l o g y o f t h e s u m m e r f l o u n d e r P a r a l i c h t h y s d e n t a t u s i n P a m l i c o Sound and - -

a d j a c e n t waters w i t h comments on P l e t h o s t i g n a and- P a l b i g u t t a i17 T h e s i s U n i r e r s i t y o f N o r t h C a r o l i n a Chapel H i l l 145 pp

P o w e l l A B and F J S c h w a r t z 1977 D i s t r i b u t i o n o f p a r a l i c h t h i d f 1 o u n d e r s ( B o t h i d a e P a r a l i c h t h s ) + i n N o r t h C a r o l i n a e s u a r i e s Chesapeake Sc i 18 334-339

~ ~ o b i e i I and J ~ i h h a r t z

t j o t h i d a e e s t u a r i e s E s t u a r i e s 2276-279

a i c h a r d s C E and M C a s t a g n a 1970 Mar ine f i s h e s o f V i r g i n i a s E a s t e r n S h o r e ( i n 1 e t and marsh s e a s i d e ( l t e r s ) Chesapeake S c i 11235-L48

R o g e r s CA 1 9 7 6 E f f e c t s o f t e m p e r a t u r e and s a l i n i t y o n t h e s u r v i v a l o f w i n t e r f l o u n d e r embryos US N a t l Mar F i s h Serv F i s h eu i 1 7452-58

Rogers SG and MJ Van Den A v y l e 1 9 8 3 S p e c i e s p r o f i l e s L i f e h i s t o r i e s a n d e n v i r o n m e n t a l r e q u i r e m e n t s o f c o a s t a l f i s h e s and i n v e r t e b r a t e s ( S o u t h A t l a n t i c ) - - summer f l o u n d e r US F i s h W i l d l Se rv FWSIOBS-8211115 US Army Corps o f Eng inee rs TR EL-82-4 14 PP-

S a i l a SB 1961 A s t u d y o f w i n t e r f l o u n d e r m o v e m e n t s L i m n o l Oceanogr 0292-295

S a i l a SB 1962a The c c n t r i b u t i o n o f e s t u a r i e s t o t h e o f f s h o r e w i n t e r f 1 o u n d e r f i s h e r y i n Rhode I s 1 arid P r o c G u l f C a r i b b F i s h I n s t 1495-109

Sai 1 a SB 19625 Proposed h u r r i - c a n e b a r r i e r s r e l a t e d t o w i n t e r f l o u n d e r movements i n N a r r a n g a n s e t t B a y T r a n s Am F i s h S o c 91 189-195

S a i l a SB DB Hor ton and RJ B e r r y 1 9 6 5 E s t i m a t e s o f t h e t h e o r e t i c a l b i o m a s s o f j u v e n i l e w i n t e r f l o u n d e r P S ~ U ~ O D ~ eu ronec tes americanus ( ~ a l baum) r e q u i r e d f o r a f i s h e r v i n Rhode I s l a n d J F i s h Res amp a r d Can 22945-995

Scarlett PG 1981 Fishery management plan for the summer flounder fishery Atlantic States Marine Fisheries Commission Management Report 81-1 Washington DC 8 0 pp

Schaaf WE DS Peters DS Vaughan L Coston-Cl ements and CW Krouse 1987 Fish population responses to chronic and acute pollution the influence of life history strategies Estuaries 10267-275

Smith RW and FC Da ibe r 1977 B i o l o g y o f t h e summer f l o u n d e r P a r a l i c h t h y s den ta tus i n Delaware Bay US N a t l Par F i s h Serv F i s h B u l l 75823-830

Smith R W LM Dery P J Scar1 e t t and A Jearld J r 1981 Proceedings o f the summer f lounder (Paral ich thvs dentatus) age and growth workshop 20-21 May 1980 Northeast Fishery Center Woods Hole Massachusetts NOAA Tech Memo NMFS-FNEC-11 31 pp

Smith WG 1973 The d i s t r i b u t i o n o f sumnier f l o u n d e r P a r a l i c h t h y s d e n t a t u s eQas and l a r v a e on t h e c o n t i n e n t a l e l f between Cape Cod and Cape Lookout 1965-1966 US N a t l Mar F i s h Serv F i s h 5 u l l 71527-548

Smolowitz RJ 1983 Mesh s i ze and the New England ground f i shery - - appl i cat i ons and imp1 i cat i ons NOAA Tech Rep NMFS-SSRF-771 60 pp

S u l l i v a n WE 1914 A d e s c r i p t i o n o f t h e younq s taqes o f t h e w i n t e r f l o u n d e r ( ~ s e d o ~ l e u r o n e c t e s a m e r i c a n u s W- F i s h Soc 44125-136

Takvor ian PM and A C a l i 1984 S e a s o n a l p r e v a l e n c e o f t h e m i c r o s P o r i d e a n G l u g e a s t e p h a n i ( Hagenmul l e r ) i n w i n t e r f l o u n d e r P s e u d o p l e u r o n e c t e s a m e r i c a n u s I W a l b a u m ) f r o m t h e New York-New Jersey LOWamp Bay Complex J F i s h B i 01 24 655-663

Topp RW 1968 An estimate o f fecundi ty o f the w in te r f lounder (Pseudo~l eu ronec te~ americanus) J Fish Res Board Can 25 1299-1302

Weins te in MP 1979 Sha l low marsh h a b i t a t s as p r i m a r y n u r s e r i e s f o r f i s h e s and s h e l l f i s h e s Cape Fear R i v e r N o r t h C a r o l i n a US N a t l M a r F i s h S e r v F i s h B u l l 77339-357

h e i n s t e i n MP and HA B r o o k s 1983 Comparat ive e c o l o g y o f nek ton r e s i d i n g i n a t i d a l c r e e k and a d j a c e n t seagrass meadow communi t y c o m p o s i t i o n and s t r u c t u r e P~ar E c o l Prog Ser 1215-27

W e i n s t e i n MP SL Weiss R G H o d s o n and LR G e r r y 1 9 8 0 R e t e n t i o n o f t h r e e t a x a o f p o s t l a r v a l f i s h e s i n an i n t e n s i v e l y f l u s h e d t i d a l e s t u a r y Cape Fear R i v e r N o r t h C a r o l i n a US N a t l M a r F i s h S e r v F i s h d u l l 78419-436

W i 1 k SJ W W Forse and DE R a l p h 1 9 7 8 L e n g t h - w e i g h t r e l a t i o n s h i p s o f f i s h e s c o l l e c t e d i n t h e New York B i g h t B u l l NJ Acad S c i 2358-64

M i l k SW WG Smith DE Ralph and J Sibunka 1980 P o p u l a t i o n s t r u c t u r e o f summer f l o u n d e r between New York and F l o r i d a based on 1 i n e a r d i s c r i m i n a n t a n a l y s i s Trans Am F i s h Soc 109265-271

W i l l i a m s AB and EE D e u b l e r 1 9 6 8 A t e n - y e a r s t u d y o f m e r o p l a n k t o n i n N o r t h C a r o l i n a e s t u a r i e s assessment o f e n v i r o n - menta l f a c t o r s and samp l ing success among b o t h i d f l o u n d e r s and penaeid shr imps Chesapeake S c i 927-41

Worobec MN 1984 F i e l d e s t i m a t e s o f t h e d a i l y r a t i o n o f w i n t e r f 1 o u n d e r P s e u d o p l e u r o n e c t e s americanus ( Wal baum) i n a s o u t h e r n New England s a l t pond J Exp Mar

Z i s k o w s k i J and R M u r c h e l a n o 1 9 7 5 F i n e r o s i o n i n w i n t e r f l o u n d e r Mar P o l l u t B u l l 626- 29

Ziskowski JJ L Despres-Patanjo R A Murchel ano A B Howe D Ralph and S Atran 1987 Disease i n commerci a1 l y valuable f i s h stocks i n the northwest A t l a n t i c Mar Po l lu t Bu l l 18496-504

I -

I - I

4 Title and Subtitle

Species P r o f i l e s L i f e H i s t o r i e s and Environmental Coastal Fishes and I n v e r t e b r a t e s ( M i d - A t l a n t i c )--Summer and Winter

5 0 1 7 1 -101

13 T Y ~ of Report 6 Period Covered US Department o f t h e I n t e r i o r US Army Corps o f Engineers F i s h and W i l d l i f e Serv ice Waterways Experiment S t a t i o n Na t iona l Net lands Research Center PO Box 631 Washington DC 20240 Vicksburg MS 39180

3 Recipients Accession NO I REPORT DOCUMENTATION 1 1 REPORT NO

PAGE I B i o l o q i c a l Report 82(11112)

F lounder 7 AuthaNs) b Barbara H Grimes Me lv in T Huish and J Howard ~ e r b ~ ~ Dav id b r a n -- a Nor th Caro l ina Cooperat ive

F i she ry Research U n i t b Na t iona l Wetlands Research Center US F i s h and W i l d l i f e S e r v i c e

Department o f Zoologyl BOX 7617 lolo Gause Boulevard N o r t h Caro l i na S t a t e U n i v e r s i t y Slidel 1 LA 70458 Raleigh NC 27695 -

12 Sponsoring Orgenizatlon Name and Address

US Army Corps o f Engineers Repor t No TR EL-82-4

2

8 Performing Organ~zation Rep( NO

lo PeTakWOrk Unit

11 Cantract(C1 or Grant(amp) NO

(c)

(GI

16 Abstract (Limit 200 words) I Species p r o f i l e s a r e l i t e r a t u r e s u m r i e s o f t h e taxonomy morphology range l i f e h i s t o r y and environmental requ i rements o f c o a s t a l species They a r e des igned t o a s s i s t i n environmental impact assessments The summer f l o u n d e r suppor t s an i m p o r t a n t commercial and r e c r e a t i o n a l f i s h e r y i n t h e M i d - A t l a n t i c and a r e i n p o r t a n t c o n s t i t u e n t o f e s t u a r i n e and c o n t i n e n t a l s h e l f systens th roughou t t h e reg ion Summer f l ounder spawning beg ins i n Septenber and w i n t e r f l ounder s p a m i n g beg ins i n June Summer f l o u n d e r eggs a r e p e l a g i c whereas w i n t e r f l o u n d e r eggs a r e demersal Summer f l ounder l a r v a e a r e more abundant i n i n l e t s and j u v e n i l e s a r e found i n e s t u a r i n e seagrass beds i n s a l i n i t i e s 2 1 2 p p t Win ter f l o u n d e r j u v e n i l e s a r e abundant i n sha l l ow bays and e s t u a r i e s moving seaward i n s p r i n g and summer Growth o f w i n t e r f l o u n d e r and summer f l o u n d e r i s seasonal There a r e probab ly t h r e e spawning popu la t i ons o f b o t h spec ies which produce a complex s tock p a t t e r n Summer f l o u n d e r a r e t o l e r a n t o f a w ide range o f chemical and phys i ca l f a c t o r s b u t p r e f e r gt 10 p p t s a l i n i t i e s W in te r f l o u n d e r op t ima l temperature i s 185 C Diseases o f w i n t e r f l ounder a r e more p r e v a l e n t i n p o l l u t e d waters Summer f l ounder a r e t o l e r a n t o f sediments l a d e n w i t h con tan i nants

17 Document Analysis a Dascripton

a1 F lounder F i s h e r i e s S a l i n i t y Growth Feeding h a b i t s Temperature L i f e cyc les -I

b ) Para1 i c h t h y s denta tus Summer f l o u n d e r Pseudopl euronectes ameri canus Winter f l ounder

I I U o c l a s s i f i e d I (See ANSI-23918)

I OPTIONAL FORM 272 (4-77)

c COSATl FieldCroup

(Formerly NT IE35) Department ol Cornmarc-

21 No of Pages la Availability Statement

U n l i m i t e d D i s t r i b u t i o n 19 Security Class (This Report) t U n c l a s s i f i e d ZO Security Class Vhis Paae)

18 22 Price

As the Nations principal conservation agency the Department of the Interior has responsibility for most of our nationally owned public lands and natural resources This includes fostering the wisest use of our land and water resources protecting our fish and wildlife preserving the environmental and cultural values of our national parks and historical places and providing for the enjoy- ment of life through outdoor recreation The Department assesses our energy and mineral resources and works to assure that their development is in the best interests of all our people The Depart- ment also has a major responsibility for American Indian reservation communities and for people who live in island territories under US administration

US DEPARTMENT OF THE INTERIOR FlSH AND WILDLIFE SERVICE

TAKE PRIDE in America

UNITED STATES DEPARTMEIUT OF THE INTERIOR

FlSH AND WILDLIFE SERVICE National Wetlands Research Center

NASA-Slidell Computer Complex 101 0 Gause Boulevard

Slidell LA 70458

POSTAQE AND FEE8 PAID U 8 DEPARTMENT OF THE INTERIOR

1157415

OFFICIAL BUSINESS PENALTY FOR PRIVATE USE $300

I -

I - I

4 Title and Subtitle

Species P r o f i l e s L i f e H i s t o r i e s and Environmental Coastal Fishes and I n v e r t e b r a t e s ( M i d - A t l a n t i c )--Summer and Winter

5 0 1 7 1 -101

13 T Y ~ of Report 6 Period Covered US Department o f t h e I n t e r i o r US Army Corps o f Engineers F i s h and W i l d l i f e Serv ice Waterways Experiment S t a t i o n Na t iona l Net lands Research Center PO Box 631 Washington DC 20240 Vicksburg MS 39180

3 Recipients Accession NO I REPORT DOCUMENTATION 1 1 REPORT NO

PAGE I B i o l o q i c a l Report 82(11112)

F lounder 7 AuthaNs) b Barbara H Grimes Me lv in T Huish and J Howard ~ e r b ~ ~ Dav id b r a n -- a Nor th Caro l ina Cooperat ive

F i she ry Research U n i t b Na t iona l Wetlands Research Center US F i s h and W i l d l i f e S e r v i c e

Department o f Zoologyl BOX 7617 lolo Gause Boulevard N o r t h Caro l i na S t a t e U n i v e r s i t y Slidel 1 LA 70458 Raleigh NC 27695 -

12 Sponsoring Orgenizatlon Name and Address

US Army Corps o f Engineers Repor t No TR EL-82-4

2

8 Performing Organ~zation Rep( NO

lo PeTakWOrk Unit

11 Cantract(C1 or Grant(amp) NO

(c)

(GI

16 Abstract (Limit 200 words) I Species p r o f i l e s a r e l i t e r a t u r e s u m r i e s o f t h e taxonomy morphology range l i f e h i s t o r y and environmental requ i rements o f c o a s t a l species They a r e des igned t o a s s i s t i n environmental impact assessments The summer f l o u n d e r suppor t s an i m p o r t a n t commercial and r e c r e a t i o n a l f i s h e r y i n t h e M i d - A t l a n t i c and a r e i n p o r t a n t c o n s t i t u e n t o f e s t u a r i n e and c o n t i n e n t a l s h e l f systens th roughou t t h e reg ion Summer f l ounder spawning beg ins i n Septenber and w i n t e r f l ounder s p a m i n g beg ins i n June Summer f l o u n d e r eggs a r e p e l a g i c whereas w i n t e r f l o u n d e r eggs a r e demersal Summer f l ounder l a r v a e a r e more abundant i n i n l e t s and j u v e n i l e s a r e found i n e s t u a r i n e seagrass beds i n s a l i n i t i e s 2 1 2 p p t Win ter f l o u n d e r j u v e n i l e s a r e abundant i n sha l l ow bays and e s t u a r i e s moving seaward i n s p r i n g and summer Growth o f w i n t e r f l o u n d e r and summer f l o u n d e r i s seasonal There a r e probab ly t h r e e spawning popu la t i ons o f b o t h spec ies which produce a complex s tock p a t t e r n Summer f l o u n d e r a r e t o l e r a n t o f a w ide range o f chemical and phys i ca l f a c t o r s b u t p r e f e r gt 10 p p t s a l i n i t i e s W in te r f l o u n d e r op t ima l temperature i s 185 C Diseases o f w i n t e r f l ounder a r e more p r e v a l e n t i n p o l l u t e d waters Summer f l ounder a r e t o l e r a n t o f sediments l a d e n w i t h con tan i nants

17 Document Analysis a Dascripton

a1 F lounder F i s h e r i e s S a l i n i t y Growth Feeding h a b i t s Temperature L i f e cyc les -I

b ) Para1 i c h t h y s denta tus Summer f l o u n d e r Pseudopl euronectes ameri canus Winter f l ounder

I I U o c l a s s i f i e d I (See ANSI-23918)

I OPTIONAL FORM 272 (4-77)

c COSATl FieldCroup

(Formerly NT IE35) Department ol Cornmarc-

21 No of Pages la Availability Statement

U n l i m i t e d D i s t r i b u t i o n 19 Security Class (This Report) t U n c l a s s i f i e d ZO Security Class Vhis Paae)

18 22 Price

As the Nations principal conservation agency the Department of the Interior has responsibility for most of our nationally owned public lands and natural resources This includes fostering the wisest use of our land and water resources protecting our fish and wildlife preserving the environmental and cultural values of our national parks and historical places and providing for the enjoy- ment of life through outdoor recreation The Department assesses our energy and mineral resources and works to assure that their development is in the best interests of all our people The Depart- ment also has a major responsibility for American Indian reservation communities and for people who live in island territories under US administration

US DEPARTMENT OF THE INTERIOR FlSH AND WILDLIFE SERVICE

TAKE PRIDE in America

UNITED STATES DEPARTMEIUT OF THE INTERIOR

FlSH AND WILDLIFE SERVICE National Wetlands Research Center

NASA-Slidell Computer Complex 101 0 Gause Boulevard

Slidell LA 70458

POSTAQE AND FEE8 PAID U 8 DEPARTMENT OF THE INTERIOR

1157415

OFFICIAL BUSINESS PENALTY FOR PRIVATE USE $300

As the Nations principal conservation agency the Department of the Interior has responsibility for most of our nationally owned public lands and natural resources This includes fostering the wisest use of our land and water resources protecting our fish and wildlife preserving the environmental and cultural values of our national parks and historical places and providing for the enjoy- ment of life through outdoor recreation The Department assesses our energy and mineral resources and works to assure that their development is in the best interests of all our people The Depart- ment also has a major responsibility for American Indian reservation communities and for people who live in island territories under US administration

US DEPARTMENT OF THE INTERIOR FlSH AND WILDLIFE SERVICE

TAKE PRIDE in America

UNITED STATES DEPARTMEIUT OF THE INTERIOR

FlSH AND WILDLIFE SERVICE National Wetlands Research Center

NASA-Slidell Computer Complex 101 0 Gause Boulevard

Slidell LA 70458

POSTAQE AND FEE8 PAID U 8 DEPARTMENT OF THE INTERIOR

1157415

OFFICIAL BUSINESS PENALTY FOR PRIVATE USE $300