Biological Report 82(11.98)

February 1989

Species Profiles: Life Histories andEnvironmental Requirements of Coastal Fishesand Invertebrates (Mid-Atlantic)

SPOT

TR EL-82-4

Coastal Ecology GroupWaterways Experiment StationFish and Wildlife Service

U.S. Department of the Interior U.S. Army Corps of Engineers

Biological Report 82(11.98)TR EL-82-4February 1989

Species Profiles: Life Histories and Environmental Requirementsof Coastal Fishes and Invertebrates (Mid-Atlantic)

SPOT

by

J. M. Phillips, M. T. Huish, and J. H. KerbyNorth Carolina Cooperative Fishery Research Unit

U.S. Fish and wildlife ServiceNorth Carolina State University

Zoology DepartmentRaleigh, NC 27695

and

D. P. MoranU.S. Fish and Wildlife Service

National Wetlands Research Center1010 Gause Blvd.Slidell, LA 70458

Project ManagerEdward Pendleton

U.S. Fish and Wildlife ServiceNational Wetlands Research Center

1010 Gause BoulevardSlidell, LA 70458

Performed forCoastal Ecology Group

Waterways Experiment StationU.S. Army Corps of Engineers

Vicksburg, MS 39180

and

U.S. Department of InteriorFish and Wildlife ServiceResearch and Development

Washington, DC 20240

This series may be referenced as follows:

U.S. Fish and Wildlife Service. 1988. Species profiles: life histories andenvironmental requirements of coastal fishes and invertebrates. U.S. FishWildl. Serv. Biol. Rep. 82(11.). U.S. Army Corps of Engineers, TR EL-82-4.

This profile may be referenced as follows:

Phillips, J.M., M.T. Huish, J.H. Kerby, and D.P. Moran. 1989. Species profiles:life histories and environmental requirements of coastal fishes andinvertebrates (mid-Atlantic)--spot. U.S. Fish Wildl. Serv. Biol. Rep.82(11.98). U.S. Army Corps of Engineers, TR EL-82-4. 13 pp.-

CONVERSION TABLE

Multiply

millimeters (mm)centimeters (cm)meters (m)meters (m)kilometers (km)kilometers (km)

square meters (M2

)

square kilometers (km 2 )hectares (ha)

liters (1)cubic meters (m

3)

cubic meters (m3

)

milligrams (mg)grams (g)kilograms (kg)metric tons (t)metric tons (t)

kilocalories (kcal)Celsius degrees ('C)

inchesinchesfeet (ft)fathomsstatute miles (Wi)nautical miles (nmi)

square feet (ft 2 )square miles (mi 2 )acres

gallons (gal)cubic feet (ft

3)

acre-feet

Metric to U.S. Customary

B03

0.039370.3937

3.2810.54680.62140.5396

10.760.38612.471

0.264235.310.0008110

0.000035270.035272.205

2205.01.102

3.968

1.8(0 C) + 32

U.S. Customary to Metric

25.402.540.30481.8291.609

-1.852

To Obtain

inchesinchesfeetfathomsstatute milesnautical miles

square feetsquare milesacres

gallonscubic feetacre-feet

ouncesouncespoundspoundsshort tons

British thermal unitsFahrenheit degrees

millimeterscentimetersmetersmeterskilometerskilometers

0.09292.5900.4047

3.7850.02831

1233.0

28350.028.350.45360.000450.9072

0.25200.5556 (OF - 32)

ounces (oz)ounces (oz)pounds (lb)pounds (lb)short tons (ton)

British thermal units (Btu)Fahrenheit degrees (IF)

square meterssquare kilometershectares

literscubic meterscubic meters

milligramsgramskilogramsmetric tonsmetric tons

kilocaloriesCelsius degrees

iv

CONTENTS

Page

PREFACE ........................ .................................... . i.i.CONVERSION FACTORS ................... ........... .... ..... ... ...... ivACKNOWLEDGMENTS ... ............................. .... ............ .. vi

NOMENCLATURE/TAXONOMY/RANGE ............ ........................... . I.. 1MORPHOLOGY/IDENTIFICATION AIDS ...... ........................ ........ 1REASON FOR INCLUSION IN SERIES ................... ....................... 3LIFE HISTORY ............................ .................... . ......... 3

Spawning ....................................... ................. 3Eggs, Larvae, and Juveniles . . . . . . . . . . . . . . . . . . . . . . . . 4Migrations .... .................. . ....................... . .... 4

GROWTH CHARACTERISTICS ....................... ........................... 5COMMERCIAL AND SPORT FISHERIES ......... ............................. 6ECOLOGICAL ROLE . . .................... ..................... . .. ...... 6

Food ...... ............................. 6Predation ................ ................................. ...... 7

ENVIRONMENTAL REQUIREMENTS ................................................. 8Temperature, Salinity, and Dissolved Oxygen ............ ................ 8Chemical Tolerances ........................ ........................... 8

LITERATURE CITED ................... ....................... ........... 9

v

ACKNOWLEDGMENTS

We are sincerely grateful to Mrs. Dorothy Wright for typing and placingthis document on computer and for proofreading the material.

The work was supervised by the North Carolina, Cooperative Fishery ResearchUnit which is sponsored by the North Carolina Wildlife Resources Commission,North Carolina State University, and the United States Fish and Wildlife Service.

We are thankful for peer reviews by William Hettler of the National MarineFisheries Service, Beaufort, North Carolina, and Charles Wenner of the SouthCarolina Marine Resources Research Institute, Charleston.

vi

F/X -,

Figure 1. Spot (Mid-Atlantic).

SPOT

NOMENCLATURE/TAXONOMY/RANGE

Scientific name ............. Leiostomusxanthurus Lacepede (Figure 3 1

Preferred common name ............. SpotOther common names ....... Flat croaker,

Norfolk spot, golden croaker (duringspawning season), croaker, goody,Cape May goody, silver gudgeon,lafayette, roach, chub, jimmy

Class ..................... OsteichthyesOrder ...................... PerciformesFamily .............. Sciaenidae - drumsGeographic range: Estuarine and

coastal waters from Cape Cod to theBay of Campeche in Mexico (Dahlberg1976; Ross 1980); especiallyabundant in the estuaries in summerand. fall from Delaware Bay toGeorgia. Also reported to occur infreshwater as far as 23 mi upstreamfrom brackish water (Raney andMassman 1953; Massman 1954) (Figure2).

MORPHOLOGY/IDENTIFICATION AIDS

Dorsal spines and rays X-XI+I,29-35; anal spines and rays II, 12-13;vertebrae 25 (10 precaudal and 15caudal); lateral line scales, 72-77;gill rakers short, 8 to 12 on theupper limb and 20 to 24 on the lowerlimb of the first arch (Hildebrand andSchroeder 1927; .Miller and Jorgenson1973; Chao 1978). Body rather shortand deep, with five marginal and fiveupper pores on the snout, and fivemental pores at the tip of the lowerjaw, barbels absent; tail broad andtruncate in young but notably concavein adults (Chao and Musick 1977;Hildebrand and Schroeder 1927).Pelvic fins moderately long, insertedjust behind the base of the pectoralfins; pectoral fins reach well beyondthe tips of the pelvic fins in adults,much shorter in young (Hildebrand andSchroeder 1927). Larvae with an

1

.~ ,.~,

NEW YORK

A TLANT/C OCEAN

BALTIMORE 4

MILES0 50 100

O 50 100KILOMETERS

El Coastal distribution

!RAS

Figure 2. Distribution of spot in the Mid-Atlantic Region.

2

oblique terminal mouth becominginferior once larval length reachesabout 25 mm (Hildebrand and Cable1930). The number of premaxillary anddentary teeth increase until fishlength reaches 60 mm (SL), at whichtime the dentary teeth begin to fallout, becoming completely absent infish greater than 100 mm (SL) inlength (Govoni 1987). Upper jawsomewhat protrusible, gape small;villiform teeth in broad bands on thepremaxillaries (juveniles only), andinner row of dentaries enlarged,canines absent (Chao and Musick 1977).

Larval spot 7-15 mm long can beseparated from other sciaenids by thepresence of 12 anal rays and theabsence of pigmentation (Pearson1928). Postlarvae of spot andAtlantic croaker (Micropogoniasundulatus) can be differentiated bytheir caudal fins, which are squarelytruncated in spot and pointed inAtlantic croakers (Welsh and Breder1923). Larval and postlarvaldevelopment in spot was described byHildebrand and Cable (1930), Johnson(1978),and Powell and Gordy (1980).

Color in life: an ill-definedrow of faint melanophores on eachside of the anterior body in newlyhatched larvae. A faint dorsal and afaint ventral melanophore locatedabout midbddy and several more faintmelanophores at the dorsal midlineshortly after hatching. Dorsalmelanophores decreasing and ventralmelanophores increasing in number aslarvae grow. Finally, a single rowof melanophores along the ventralmidline becomes established in thelate yolk-sac stage and persiststhroughout. the larval period (Powelland Gordy 1980).

Fish 20-50 mm long, mostly pale;sides of head silvery; sides of bodyand back each with a row of darkb l otches composed of duskypunctations, besides other irregularlyplaced dusky points. Fish longer than50 mm, bluish gray with golden

reflections above; silvery underneath;sides with 12 to 15 oblique yellowishbars, becoming indistinct in verylarge fish; a large yellowish-blackshoulder spot present, except in veryyoung; fins mostly pale yellow; dorsaland caudal fins more or less dusky;anal and pelvics also partly dusky inlarge fish (Hildebrand and Schroeder1927; Pearson 1928).

REASON FOR INCLUSION IN SERIES

Spot are important to bothrecreational anglers and commercialfishermen in the Mid-Atlantic Region(Pacheco 1962a; Kjelson and Johnson1976; Hodson et al. 1981b; Ross 1980).They constitute a major proportion ofthe biomass and numbers of fishpresent in estuarine waters of thisregion (Pacheco 1962a; Kjelson andJohnson 1976; Markle 1976; Shenker andDean 1979). Consequently, they areconsidered to be important in thestructure and function of theseestuarine ecosystems (Kjelson andJohnson 1976).

LIFE HISTORY

Spawning

Females as small as 214 mm havebeen found with ripening ova(Hildebrand and Schroeder 1927). Thelargest fish in the populationgenerally spawn first (Hildebrand andCable 1930). Most spawn offshore overthe outer continental shelf, fromOctober to March (Hildebrand and Cable1930; Ross 1980; Lewis and Judy 1983;Miller et al. 1984; Warlen and Chester1985). According to Lewis and Judy(1983) some spot spawn inshore.Laboratory spawning has been inducedat temperatures of 17.5-25.0 oC at aphotoperiod of 8 h light and 16 h dark(Hettler and Powell 1981). Mostspawning off the coast of NorthCarolina occurs 75-95 km offshore(Warlen and Chester 1985), and peaksin December and January (Lewis andJudy 1983; Warlen and Chester 1985).

3

Eggs, Larvae, and Juveniles

From laboratory-induced spawning,the number of eggs produced per female

..ranges from 30,000 to 60,000 (Hettlerand Powell 1981). Eggs occur in thewater above the Continental Shelf inwinter (Powell and Gordy 1980;Stickney and Cuenco 1982). Eggdiameters range from 0.72 to 0.87 mm(Powell and Gordy 1980) . Theincubation period lasts about 48 hoursat a water temperature of 20 oC(Powell and Gordy 1980). The eggs andpreflexion larvae (larvae in which thenotochord has not yet begun to flex)are buoyant; the larvae probablybecome demersal during the flexionstage (Lewis and Judy 1983; Kendall etal. 1984). Larvae are about 1.5-1.7

mm long at hatching (Hildebrand andCable 1930; Powell and Gordy 1980;Warlen and Chester 1985), and beginfeeding when they are 3 days old at 240Q, and when they are 6 days old at 18oC (Powell and Chester 1985). Larvaeup to 21,days old exhibit irreversiblestarvation when unfed for three days(Powell and Chester 1985). Olderlarvae (60-90 days) have 50% mortalityafter 20 days without food (Powell andChester 1985).

In the offshore waters of NorthCarolina (6 to about 63 nautical milesfrom land), spot larvae are most densein mid-water and at the bottom duringthe day and appear to migrate to thesurface at night (Kjelson et al.1976). In the nearshore waters (< 5nautical miles from land), larvalconcentrations are greatest on thebottom during both night and day(Kjelson et al. 1976). In datacollected in one year from January toApril, the average densities of larvalspot ranged from 0 to 59 + 81 (SD) per1000 m3 of water in the nearshore areaof Onslow Bay, and from 14 + 13 (SD)to 892 + 689 (SD) in Beauf~rt Inlet(Kjelson-et al. 1976).

The mean age and length of spotlarvae vary inversely with thedistance from shore (Kjelson et al.

1976; Lewis and Judy 1983; Warlen andChester 1985). Off North Carolina,larvae collected near the Gulf Streamwere 29 days old and < 4 mm standardlength (SL). Their average age is 59days (11.3-15.6 mnm SL) when they firstenter the Newport River estuary(Warlen and Chester 1985). Larvaeless than 11 mm long are rarelycollected in the estuaries, butpostlarvae are common in nearshore andestuarine waters (Kjelson and Johnson1976). Near the inlets, the larvaemetamorphose to juveniles (Miller etal. 1984).

In the York and Cape Fear Riversand their respective tributaries, age0 spot are densest upstream (Chao andMusick 1977, Weinstein 1979);yearlings are densest in the lowerreaches (Chao and Musick 1977). Thehighest density reported for juvenilespot was 14.9/m2 in Rose Bay, N.C.(Gilliam et al. 1985). Seagrassmeadows and tidal creeks are importantnursery habitats for postlarval andjuvenile spot (Spitsbergen and Wolff1976; Wolff 1976; Weinstein 1979;Weinstein and Brooks 1983). . Thesespot constitute as much as 80% and 90%of the total number of fish present inseagrass meadows and tidal creeks,respectively, but appear to prefermarsh creeks over seagrass meadows(Weinstein and Brooks 1983).

Migrations

In North Carolina, larvae firstmove inshore (to the Newport Riverestuary) from mid-December to mid-April and, in Onslow Bay at that time,are thought to be passivelytransported by the water currents(Warlen and Chester 1985). Juvenilespot first occur in marshes of theAlbemarle Sound and Neuse Riverestuaries in February (Hester 1975;Miller et al. 1984). The mechanism bywhich the postlarvae move into thetidal creeks and marshes is unclear.One speculation is that they stay onthe bottom during the day and on ebbtides, moving to the surface at night

4

when flood tides carry them into tidalcreeks and marshes (Weinstein et al.1980). Spot may also move into thenursery areas of drowned river valleyestuaries (where the downstreamsurface flow of the less densefreshwater causes a displacement ofwater in the lower layers, resultingin the movement of saltwater upstreamalong the bottom of the estuary).However, neither of these mechanismsis important in shallow sounds withnarrow inlets and low lunar tidalamplitudes such as those in PamlicoSound (Miller et al. 1984). There,the spot may move into the nurseriesby bottom currents created whennorthwesterly winds build up wateragainst the barrier islands resultingin a countercurrent flow in theopposite direction toward the nurseryareas (Miller et al.. 1984). Overall,early postlarval spot probably havelittle direct control over theirhorizontal movements due to thestrength of the horizontal currents.But the vertical currents are usuallyweak enough to allow postlarval spotsome potential control over theirvertical movements; thesemovements are, in turn, probably theway they control their horizontaldirection of migration (J. Miller,North Carolina State University,Raleigh; pers. comm.).

When spot first arrive in RoseBay, N.C., they tend to occur mostlyalong the shallow edges of the bay;they disperseto all depths by April,but their densities remain greatest inthe shallows (Currin 1984). In theChesapeake Bay and Albemarle Soundestuaries, young spot remain in theestuaries until September or October,and then migrate to the sea (Pacheco1962a; Hester 1975). In Neuse Riverestuaries, most spot leave by June(and probably move to Pamlico Sound)presumably due to decreases indissolved oxygen (Hester 1975).Movements of spot 150-255 mm in forklength (FL) (based on tagging studieswithin or between estuaries in thelower Chesapeake Bay) generallyranged from 5 to 74 mi over a period

of 5-155 days, although several fishmoved 178-200 mi (Pacheco 1962b).

GROWTH CHARACTERISTICS

Initial growth of larval spot offthe North Carolina coast has beenreported to be about 7% of body lengthper day (Warlen and Chester 1985).Average instantaneous growth rates(in dry weight) of larvae are about0.20 pg/pg/day at 18-23 days of ageand decrease to about 0.14 pg/pg/dayat 23-48 days (Warlen et al. 1979).By the time spot move into coastaland estuarine waters, which areoften cooler than 10 OC, growthrates decrease to less than 1.5% ofbody length per day (Warlen andChester 1985). In moving from inletsto nursery, areas in the Pamlico Sound,spot may increase from about 15 to 20

mm in length and 0.075-0.179 g in wetweight (Miller et al. 1985). Butspot may be as small as 16 mm whenthey reach the nursery areas in theJames River, Va. (McCambridge andWalden 1984). Currin et al. (1984),in a literature review, reported thatinstantaneous daily growth rates ofjuvenile spot ranged from 0.021 to0.040 g/g/d. Growth rates of spot inRose Bay, N.C., have been estimated tobe 3% per day by weight (Miller 1985).McCambridge and Walden (1984) reportedthat growth rates of spot (63-224 mmTL) range from 10.5 to 19.1 mmTL/month.

Annual production of juvenilespot in Rose Bay has been reported at7.5 g/m 2 , or 745 kg/ha, although itmay be 10 times as high in areas nearthe headwaters (Miller 1985). Aboutone-third of spot production in RoseBay is in the areas less than 1.75 min depth, or about one-fourth of thebay's area (Miller 1985). Currin etal. (1984) indicated that annual spotproduction ranges from 0.25 to 7.51g/m 2 ; however, the large range inproduction is attributed not to growthrate differences, but to differencesin the biomass (or numbers) of spotpresent.

5

Most spot are of age classes 0-Iand few are older than III;predominance of smaller fish may be anartifact of collecting gearinefficiency for larger spot (Pacheco1962a). The largest spot reported was360 mm TL (Ross 1980). Lengths by ageare variable and overlap: age-O, 80-181 mm; age-i, 122-230 mm; age-2, 215-290 mm; age-3, 275 mm (Welsh andBreder 1923; Hildebrand and Cable1930; Pacheco 1962a).

Determinants of year-classstrength have not been adequatelyinvestigated. Joseph (1972) suggestedthat year-class strength is determinedby the time postlarvae enter theestuarine nursery grounds-- indicatingthat year-to-year populationfluctuations are due to environmentalchanges at the spawning grounds or inwaters traversed by the larvae asthey move toward the estuaries.Since large-scale mortalities ofjuveniles are not observed in thenursery grounds, reduction in popu-lation numbers occurs during larvaland post-larval stages. Significantnumbers of juvenile spot, however,are killed incidentally by trawlersin Pamlico Sound, N.C. (Wolff 1972).

COMMERCIAL AND SPORT FISHERIES

The commercial fishery for spotis concentrated along the Atlanticcoast from the Chesapeake Bay throughthe Carolinas (C. Manooch, NationalMarine Fisheri-es Service, Beaufort,N.C.; pers. comm.' B. Kelly, pers.comm.). From 1972 to 1986, thelargest commercial landings of spotwere in North Carolina (Table 1).Most of the fish presently landedthere are probably used for humanconsumption (C. Manooch, per. comm.;B. Kelly, per. comm.). In NorthCarolina, spot are primarily capturedin gill nets or haul seines (Wolff1972);however, substantial numbers ofspot are landed in the scrap fisheriesin North Carolina, some of which aresold for industrial use. In Carteret

County, N.C., most of the spot landedin trawls between 1969 and 1971 (about463,000 pounds) were sold as scrapfish (Wolff 1972). Additionalincidental captures in shrimp trawls*and with miscellaneous gears wereestimated to equal about 32 millionpounds; although these fish werereturned to the water, few are likelyto have survived (Wolff 1972).

North of the Chesapeake Bay,combined catches of spot have notreached 100,00.0 lb since 1958, andfrom 1960 to 1965, the combined catchhas been less than 1,000 lb (Joseph1972).

ECOLOGICAL ROLE

Food

Early stages of spot (1-10mm) eatplankton such as pteropods, larvalpelecypods, and cyclopoid copepods(Govoni et al. 1983). Spot 11-20 mmlong feed primarily on calanoid,harpacticoid and cyclopoid copepods,mysids, and amphipods (Kjelson et al.1975; Livingston 1982; Currin 1984).In the process of migrating to theestuaries from the Continental Shelf,larval . spot (and other species) maysignificantly decrease the zooplanktonstanding crop (Thayer et al. 1974).Juvenile spot are nonterritorial,benthic, grazing generalists (Hodsonet al. 1981a; Woodward 1981;Livingston 1982) that forageeffectively regardless of substratetype (Gerry 1981)--though they prefersand or mud (Ross 1980; Cowan andBirdsong 1985). Juvenile spotsometimes reduce benthic infaunaldensities and species richness(Virnstein 1977). In the York Riverestuary, as spot increase in size togreater than 20 mm SL. calanoids andnematodes decrease in importance inthe diet while harpacticoids,amphipods, and polychaetes increasein importance. All sizes of spotpresent eat bivalve siphons andmaldanid polychaete tails (Smithet al. 1984). Juvenile spot in

6

Table 1. Commercial landings (thousands of pounds) of spot and their value(thousands of dollars) by state along the Mid-Atlantic coast, from 1972-86.(U.S. Dep. Commerce, and N.C. landings, N.C. Div. Marine Fisheries; unpubl. data).

NY NJ DEL MA VA NC

Year lbs $ lbs $ lbs $ lbs $ lbs $ lbs $

1972 * * 1 1 * * 74 12 2,951 322 3,902 3781973 * * 10 1 * * 27 5 2,576 361 5,398 6761974 * * 11 2 * * 37 5 2,251 349 5,607 .6251975 * * 59 11 7 4 103 11 1,918 276 8,300 8611976 3 1 1 1 8 1.2 16 3 1,192 224 2,647 3481977 6 1 20 3 11 3 16 2 1,867 388 3,805 4691978 1.2 0.3 11 3 19 3 31 5 3.205 593 4,879 6271979 0.3 0.1 2 0.3 18 4 11 2 2,541 513 7,304 1,4301980 1 0.6 2 0.5 5 2 6 2 1,795 591 7,100 1,4941981 * * 6 3 11 3 14 5 1,025 411 3,511 8241982 * * 2 0.3 2 2 6 2 1,017 390 .4,919 1,0801983 * * 0.8 0.4 * * 129 53 1,568 490 2,952 6851984 * * 0.1 0.02 * * 43 18 735 261 3,487 8141985 * * 2 0.4 17 5 8 4 1,562 574 4,044 8741986 * * 7 2 86 30 104 43 1,840 589 3,354 772

* None reported

the shallow bays of Pamlico Sound,N.C., feed primarily on harpacticoids,nematodes, clam siphons, dipterans,and polychaetes (Gerry 1981; Currin1984).

Adult spot feed by scooping upbenthic sediments in their mouth,followed by chewing and then spittingout unwanted material (Roelofs 1954).Their main diet consists of polychaeteannelids and copepods, with decapods,nematodes, and diatoms making up fooditems of lesser importance (Roelofs1954; Chao and Musick 1978).Different diets of spot in differentlocations are probably due to thepresence of different prey types(Currin 1984).

Kjelson et al. (1975) reportedthat larvae begin feeding at dawn, andattain a maximum gut content by aboutmidday; however, Hodson et al. (1981a)found that stomachs of spot (9-124 mmSL) are fuller at night than duringthe day. Daily rations of postlarval

spot (about 9-25 mm SL) and juvenilespot (> about 25 mm SL) range from4.3% to 9.0% of body weight,probablydepending on food availability.(Kjelson et al. 1975; Kjelson andJohnson 1976). Using these dailyration values, Currin et al. (1984)calculated mean consumption to be from5.89 to 284.4 mg (dry wt)/m 2 daily.

Predation

Chaetognaths (arrow-worms) areone of the most abundant planktonicpredators in the waters over theContinental Shelf during and immedi-ately after the winter spawning ofspot. But their predation on larvalspot is thought to be less importantthan their effect as a competitor forfood (Clements 1979). Large fish,which may be predators of juvenilespot, usually live in the deeper areasof bays where salinities are stable,rather than in the shallower areaswhere salinity fluctuates greatly;however, spot occur in both deep and

7

shallow areas of bays (Gerry 1981;Miller et al. 1984). In Rose Bay,N.C., from mid-May to mid-July, theinstantaneous daily mortality of spotwas -0.0313--a large proportion ofwhich was credited to predation indeep areas of the bay (Currin 1984;Miller et al. 1984). Spot areconsidered to be of some importance asa food 'for cormorants (Phalacrocoraxauritus) and spotted seatrout(Cynoscion nebulosus) (Pearson 1928;Thayer et al. 1976). Spot are also,to a limited degree, a food source forstriped bass (Morone saxatilis) inAlbemarle Sound, N.C. (Nianooch 1972);but they have been a major componentin the diet of striped bass in theChesapeake Bay (Hollis 1952).

ENVIRONMENTAL REQUIREMENTS

Temperature, Salinity, and DissolvedOxygen

Spot have been found attemperatures of 8-31 oC (Wolff 1976).The lower lethal temperature for spotis thought to be 4-5 oC, varying withthe size of fish, the rapidity of thetemperature drop, and the duration ofexposure (Dawson 1958). In thelaboratory, postlarval and juvenilespot smaller than 25 mm SL have anupper -incipient lethal temperature of35.2 °C at a salinity of 20 ppt. Atincreasing salinities, time to, deathincreases, but the lethal temperaturedecreases (Hodson et al. 1981b).

Spot have been found atsalinities of 0-60 ppt (Hedgpeth 1967;Wolff 1976; Cowan and Birdsong 1985).Juvenile spot in York Rivertributaries occur primarily in creekswith salinities of 16 ppt or greater(Smith et. al. 1984). In PamlicoSound, N.C., spot are most abundant intributaries with relatively lowsalinities (Spitsbergen and Wolff1976). Early life history stages ofspot appear to be able to toleraterelatively high salinity fluctuations(Gerry 1981; Gilliam et al. 1985).But it has been speculated,that spot

move away from their primary nurserygrounds due to their decreasedtolerance of salinity fluctuations asthe fish age (Miller et al. 1984), andyet recent experiments indicate thatsalinity fluctuations do not influencejuvenile spot distributions (Moser1985).

For juvenile spot at 28 °Cexposed for I and 96 h, the LC5 0values for dissol-ved oxygen are 0.49and 0.70 mg/L, and the LC9 5 values are0.43 and 0.60 mg/L (Burton et al.1980). Oxygen consumption by spot(respiration rate) increases with fishweight, swimming speed, .and activity(Neumann et al. 1981). Spot appear tobe more efficient oxygen consumersthan striped bass or white perch(Morone americanus) (Neumann et al.1981).

Chemical Tolerances

Chemicals that reach theestuarine system in runoff, in treatedsewage, and in water used to coolpower plants may form compounds thatare toxic to fish. The hatchingsuccess of spot eggs tends to beinversely related to concentrations of5-chlorouracil (a chloro-organiccompound) at greater than 40 ppb(Warlen and Lewis 1976). In larvalspot exposed to chlorine -producedoxidants at 0.47 ppm for 3-30 min at 9'C, survival ranged from 80% to 100%.When the temperature was raised to 12oC with a concentration of 0.43 ppm,

however, survival fell from 40% to zeroas exposure time increased from 5 to30 min (Warlen and Lewis 1977). Inpostlarval spot exposed to copper inthe form of CuC1 2 , toxicity increasedwith time: LC50 values decreased from0.59 mg Cu/L for 4 days of exposure,to 0.16 mg Cu/L for 14 days ofexposure (Engle and Thuotte 1976).The LC50 values based on pCu (negativelog of the free cupric ion activity)ranged from 9.0 to 9.2 for egg tohatching, and 8.4 to 8.6 for larvae(Engle et al. 1976).

8

LITERATURE CITED

Burton, D.T., L. Richardson, and C.Moore. 1980. Effect of oxygenreduction rate and constant lowdissolved oxygen concentrations ontwo estuarine fish. Trans. Am.Fish. Soc. 109:552-557.

Chao, L.N. 1978. A basis forclassifying western AtlanticSciaenidae (Teleoste: Perci-formes). U.S. Natl. Mar. Fish.Serv. Circ. 415. 64 pp.

Chao, L.N., and J.A. Musick. 1977.Life history, feeding habitý andfunctional morphology of juvenilesciaenid fishes in the York RiverEstuary, Virginia. U.S. Natl. Mar.Fish. Serv. Fish. Bull. 75:657-702.

Clements, L.C. 1979. Preliminarystudies on chaetognaths as plank-tonic predators of fish larvae.Ann. Rep. U.S. Natl. Mar. Fish.Serv. Lab., Beaufort, N.C.

Cowan, J.H., and R.S. Birdsong. 1985.Seasonal occurrence of larval andjuvenile fishes in a VirginiaAtlantic coastal estuary withemphasis on drums - (FamilySciaenidae). Estuaries 8:48-59.

Currin, B.M. 1984. Food habits anafood consumption of juvenile spot,Leiostomus xanthurus, and croaker,Micropogonias undulatus, in theirnursery areas. M.S. Thesis. NorthCarolina State University, Raleigh.103 pp.

Currin, B.M., J.P. Reed, and J.M.Miller. 1984. Growth, production,food consumption, and mortality ofjuvenile spot and croaker: a

comparison of tidal and nontidalnursery areas. Estuaries 7:451-459.

Dahlberg, M.D. 1976. Guide to coast-al fishes of Georgia and nearbystates. University of GeorgiaPress, Athens. 187 pp.

Dawson, C.E. 1958. A study of thebiology and life history of thespot, Leiostomus xanthurusLacepede, with special reference to

°South Carolina. Contri. BearsBluff Lab. No. 28, pp. 48.

Engle, D.W., W.G. Sundra, and R.M.Thuotte. 1976. The effects ofcupric ion activity on the survivalof eggs and postlarvae of the spot,Leiostomus xanthurus. Pages 431-436 in Atlantic EstuarineFisher--es Center annual report tothe Energy Research and DevelopmentAgency, U.S. Natl. Mar. Fish. Serv.,Beaufort, N.C.

Engle, D.W., and R.M. Thuotte. 1976.The effects of copper on thesurvival of postlarval fish. Pages423-430 in Atlantic Estuarine Fisheries Center annual report to theEnergy Research and DevelopmentAgency, U.S. Natl. Mar. Fish. Serv.,Beaufort, N.C.

Fisheries of the United States, 1985.U.S. Natl. Mar. Fish. Serv., Curr.Fish. Stat. No. 8380. 122 pp.

Gerry, L.R. 1981. The effects ofsalinity fluctuations and salinitygradients on the distribution ofjuvenile spot, Leiostomus xanthurus,

9

and croaker, Micropogoniasundulatus. M.S. Thesis. NorthCarolina State University, Raleigh.57 pp.

Govoni, J.J. 1987. The ontogeny ofdentition in Leiostomus xanthurus.Copeia 1987:1041I-046.

Govoni, J.I., .EE. Hoss, and A.J.Chester. 1983. Comparativefeeding of three species of larvalfishes in the Northern Gulf ofMexico: Brevoortia patronus,Leiostomus xanthurus, andMicropogonias undulatus. Mir. Ecol.Prog. Ser. 13:189-199.

Gunter, G. 1950. Correlation betweentemperature of water and size ofmarine fishes on the Atlantic andGulf Coasts of the United States.Copeia 1950:298-304.

Hata, D.N. 1985. Aspects of the lifehistory and population dynamics ofthe spot, Leiostomus xanthurus, inthe northwestern Gulf of Mexico (May1985). M.S. Thesis. Texas A&MUniversity. 88 pp.

Hedgpeth, J.W. 1967. Ecologicalaspects of the Laguna Madre, ahypersaline estuary. Pages 383-389in G. H. Lauff, ed. Estuaries.American Association for theAdvancement of Science Publ. No. 83.

Hester, J.M. , Jr. 1975. Nektonpopulation dynamics in the AlbemarleSound and Neuse River estuaries.M.S. Thesis. North Carolina StateUniversity, Raleigh. 129 pp.

Hettler, W.F., and A.B. Powell. 1981.Egg and larval fish production atthe NMFS Beaufort Laboratory, N. C.,USA. Rapp. P.-V. Reun. Cons. Int.Explor. Mer 178:501-503.

Hildebrand, S.F., and L.E. Cable.1930. Fourteen teleostean fishes atBeaufort, N.C. Bull. U.S. Bur.Fish. 46:383-488.

Hildebrand, S.F., and W.C. Schroeder.1927. Fishes of Chesapeake Bay.Bull. U.S. Bur. Fish. 43:1-366.

Hodson, R.G., J.0. Hackman, and C.R.Bennett. 1981a. Food habits ofyoung spots in nursery areas of theCape Fear River estuary, NorthCarolina. Trans. Am. Fish. Soc.110:495-501.

Hodson, R.G., R.G. Fechelm, and R.J.Monroe. 1981b. Upper temperaturetolerance of spot, Leiostomus xanth-urus, from the Cape Fear River estu-ary, North Carolina. Estuaries4:345-356.

Hollis, E.H. 1952. Variations in thefeeding habits of the striped bass,Roccus saxatilis (Walbaum) inChesapeake Bay. Bull. BinghamOceanogr. Collect. Yale Univ.14:111-131.

Johnson, G.D. 1978. Development offishes in the Mid-Atlantic Bight.Vol . IV. Carangidae throughEphippidae. U.S. Fish Wildl. Serv.Biol. Serv. Program FWS/OBS-78/12.Pages 203-211.

Joseph, E.B. 1972. The status ofthe sciaenid stocks of the MiddleAtlantic Coast. Chesapeake Sci.13:87-100.

Kendall, A.W.,Jr., E.H. Ahlstrom, andH.G. Moser. 1984. Early lifehistory stages of fishes and theircharacteristics. Pages 11-22 inOntogeny and systematics of fishes.Special Publication No. 1. AmericanSociety of Ichthyologists andHerpetologists. Allen Press Inc.,Lawrence, KS.

Kielson, M.A., D.S. Peters, G.W.Thayer, and G.N. Johnson. 1975.The general feeding ecology ofpostlarval fishes in the NewportRiver Estuary. U.S. Natl. Mar.Fish. Serv. Fish. Bull. 73:137-144.

10

Kjelson, M.A., and G.N. Johnson.1976. Further observations of thefeeding ecology of postlarvalpinfish, Lagodon rhomboides, andspot, Leiostomus xanthurus. U.S.Natl.. Mar. Fish. Serv. Fish. Bull.

.74:423-432.

Kjelson, M.A., G.N. Johnson, R.L.Garner, and J.P. Johnson. 1976.The horizontal-vertical distributionand sample variability of ichthyo-plankton populations within thenearshore and offshore ecosystems ofOnslow Bay. Pages 287-341 inAtlantic Estuarine Fisheries Centerannual report to the Energy Researchand Development Agency, U.S. Natl.Mar. Fish. Serv., Beaufort, N.C.

Lewis, R.M., and M.H. Judy. 1983.The occurrence of spot, Leiostomusxanthurus, and Atlantic croaker,Mfcropogonias undulatus, larvae inOnslow Bay an Newport Riverestuary, North Carolina. U.S. Natl.Mar. Fish. Serv. Fish. Bull.81:405-412.

Livingston, R.J.. 1982. Trophicorganization of fishes in a coastalseagrass system. Mar. Ecol. Prog.Ser. 7:1-12.

Manooch, C.S. 1972. Food habits ofadult and yearling striped bass,Morone saxatilis (Walbbaum) fromAlbemarle Sound, North Carolina.M.S. Thesis. North Carolina StateUniversity, Raleigh. 94 pp.

Markle, D.F. 1976. The seasonalityof availability and movements offishes in the channel of the YorkRiver, Virginia. Chesapeake Sci.17:50-55.

Massman, W.H. 1954. Marine fishes infresh and brackish waters ofVirginia rivers. -Ecology 35:75-78.

McCambridge, J.T., Jr., and R.W.Walden, I1I[. 1984. Growth ofjuvenile spot, Leiostomus xanthurusLacepede, in the nursery region of

the James River, Virginia.Estuaries 7:478-480.

Miller, G.L. , and S.C. Jorgenson.1973. Meristic characters of somemarine fishes of the westernAtlantic Ocean. U.S. Natl. Mar.Fish. Serv. Fish. Bull. 71:301-312.

Miller, J.M. 1985. The effects offreshwater discharge into primarynursery areas for juvenile fish andshellfish: criteria for theirprotection. Pages 62-84 in Watermanagement and estuarine nurseries.University of North Carolina SeaGrant Publication 85-2.

Miller, J.M., J.P. Reed, and L.Pietrafesa. 1984. Patterns,mechanisms and approaches to thestudy of migrations' of estuarine-dependent fish larvae and juveniles.Pages 205-225 in J.D. McCleave, G.P.Arnold, J.J. Johnson, and W.H.Neill, eds. Mechanisms of migrationin fishes. Plenum Press, New York.544 pp.

Miller, J.M., L.B. Crowder, and M.L.Moser. 1985. Migration andutilization of estuarine nurseriesby juvenile fishes: an evolutionaryperspective. Contrib. Mar. Sci.27:338-342.

Moser, M.L. 1985. Effects ofsalinity fluctuations on juvenileestuarine fish. Estuaries8(2B) :9A.

Neumann, D.A., J.M. O'Connor, and J.A.Jerk, Jr. 1981. Oxygen consumptionof white perch (Morone americanus),striped bass (M. saxatilis and spot(Leiostomus xanthurus). Comp.Biochem. Physiol. 69A:467-478.

Pacheco, A.L. 1962a. Age and growthof spot in lower Chesapeake Bay,with notes on distribution andabundance of juveniles in the YorkRiver System.. Chesapeake Sci.3:18-28.

11

Pacheco, A.L. 1962b. Movements ofspot, Leiostomus xanthurus, in thelower Chesapeake Bay. ChesapeakeSci. 3:256-257.

Pearson, J.C. 1928. Natural historyand conservation of the redfish andother commercial sciaenids of theTexas Gulf. Bull. U.S. Bur. Fish.44:129-214.

Powell, A.B., and A.J. Chester. 1985.Morphometric indices of nutritionalcondition and sensitivity tostarvation of spot larvae. Trans.Am. Fish. Soc. 114:338-347.

Powell, A.B., and H.R. Gordy. 1980.Egg and larval development of thespot Leiostomus xanthurus (Sciae-nidae). U.S. Natl. Mar. Fish. Serv.Fish. Bull. 78:701-714.

Raney, E.C., and W.C. Massman. 1953.The fishes of the tidewater sectionof the Pamunkey River, Virginia.J. Wash. Acad. Sci. 43:424-432.

Roelofs, E.W. 1954. Food studies ofyoung scianid fishes, Microeoganand Leiostomus from North Carolina.Copeia 195:151-153.

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Shenker, J.M., and J.M. Dean. 1979.The utilization of an intertidalsalt marsh creek by larval andjuvenile fishes: abundance,diversity and temporal variation.Estuaries 2:154-163.

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Spitsbergen, D.L., and M. Wolff.1976. Survey of nursery areas inwestern Pamlico Sound, NorthCarolina. Completion Rep. forProject No. 2-175-R. N.C.Department of Natural Resources,Division of Marine Fisheries,Morehead City, N.C. 80 pp.

Stickney, R.R., and M.L. Cuenco.1982. Habitat suitability indexmodels: juvenile spot. U.S. FishWildl. Serv. Biol. Serv. ProgramFWS/OBS-82/10.20. 13 pp.

Thayer, G.W., D.E. Hoss, M.A. Kjelson,W.F. Hettler, Jr., and M.W. LaCroix. 1974. Biomass ofzooplankton in the Newport RiverEstuary and the influence ofpostlarval fishes. Chesapeake Sci.15:9-16.

Thayer, G.W., M.A. Kjelson, and T.J.Price. 1976. Feeding habits ofavian populations utilizing theestuarine area near Beaufort. Pages356-363 in Atlantic EstuarineFisheries Center annual report tothe Energy Research and DevelopmentAgency, U.S. Natl. Mar. Fish. Serv.,Beaufort, N.C.

Virnstein, R.W. 1977. The importanceof predation by crabs and fishes onbenthic infauna in Chesapeake Bay.Ecology 58:1199-1217.

Warlen, S.M., and C.W. Lewis. 1976.A preliminary report on the effectsof two chloro-organics on severalestuarine organisms. Pages 405-411in Atlantic Estuarine FisheriesCenter annual report to the EnergyResearch and Development Agency,U.S. Natl. Mar. Fish. Serv.,Beaufort, N.C.

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12

Warlen, S.M., A. Powell, M. Boyd, P.Howland, M. Look, and 0. Lewis.1979. Age and growth of larval spot(Leiostomus xanthurus) and Atlanticmenhaden (Brevoortia tyrannus) withestimates of their spawning times.Pages 465-482 in Annual report ofNatl . Mar. Fish. Serv. Lab.,Beaufort, N.C.,

Warlen, S.M., and A.J. Chester. 1985.Age, growth and distribution oflarval spot, Leiostomus xanthurus,off North Carofi-na.U.S. Nati. Mar.Fish. Serv. Fish. Bull. 83:587-599.

Weinstein, M.P., and H.A. Brooks.1983. Comparative ecology of nektonresiding in a tidal creek andadjacent seagrass meadow: communitycomposition and structure. Mar.Ecol. Prog. Ser. 12:15-28.

Weinstein, M.P. 1979. Shallow marshhabitats as primary nurseries forfishes and shellfish, Cape FearRiver, North Carolina. U.S. Natl.Mar. Fish. Serv. Fish. Bull. 77:339-357.

Weinstein, M.P., S.L. Weiss, R.J.Hodson, and L.R. Gerry. 1980.Retention of three taxa of post-

larval fishes in an intensivelyflushed tidal estuary, Cape FearRiver, North Carolina. U.S. Natl.Mar. Fish. Serv. Fish. Bull. 78:419-436.

Welsh, W.W., and C.M. Breder. 1923.Contributions to life history ofSciaenidae of the eastern UnitedStates Coast. Bull. Bur. Fish.39:141-201.

Wolff, M. 1972. A study of the NorthCarolina scrap fishery. N.C. Dep.Nat. Econ. Resour. Div. Comm.Sports Fish. Spec. Sci. Rep. No.20. 29 pp.

Wolff, M. 1976. Nursery area surveyof the outer banks region.Completion Rep. for Project No. 2-222-R. N.C. Department of NaturalResources, Division of MarineFisheries. Morehead City, N.C. 47pp.

Woodward, J.L. 1981. Enclosurestudies of food resource parti-tioning between juvenile spot andcroaker. M.S. Thesis. North Caro-lina State University, Raleigh. 42pp.

13

16272"*lfll

REPORT DOCUMENTATION I. REPORT NO 2. 3. Reec,o..'s Acc*,o. No.

PAGE Biological Report 82(11.98)*__"

4. Title and Subttl S.• Report Data

Species Profiles: Life Histories and Environmental Requirements February 1989of Coastal Fishes and Invertebrates (Mid-Atlantic): Spot 6-

7. Authlgos) a brformrng Organzation Root No.

J.H. Phillips, M.T. Huish, J.H. Kerby, and D.P. %branb

1. Porfo.•- O san.zato!'6 Nain and Addres s0. bt.0iect/Task/Wo.1 Unit No.

aN.C. Cooperative Fishery Research Unit bNational Wetlands ResearchDepartment of Zoology, Box 7617 Center Ii. CWtrc,(C) of Grnt(G) No.

North Carolina State University U.S. Fish and Wildlife Service c,Raleigh, NC 27695 Slidell, LA 70458 (G)12. Soonsoi.ng Organization Nam. and Add,",(s

U.S. Department of the Interior U.S. Army Corps of Engineers . TyPe ofRepor&APnoridCo,..d

U.S. Fish and Wildlife Service Waterways Experiment StationNational Wetlands Research Center P.O. Box 631Washington, D.C. 20240 Vicksburg, MS 39180 14.

15. Supplementary Notes

*U.S.Army Corps of Engineers Report No.TR EL-82-4

16. A•ta• (UWit: 200 words)

Spot (Leiostomus xanthurus) is an important species to recreational fishermenand to the commercial fishing industry. Landings in Virginia are reported to benearly 2 million pounds annually and in North Carolina 3 to 7 million pounds.

Spot are distributed throughout the Mid-Atlantic area and their larvae arefound up to 63 nautical miles from land. The larvae are reported to metamorphose tothe juvenile phase near estuarine inlets and the juveniles appear in estuaries fromabout mid-December to mid-April where they remain until September or October. Thejuveniles may constitute 80%-90% of the total number of fish present in tidal creeksand seagrass meadows. Growth rates (weight) of juvenile spot vary but are reportedas 3% per day. Lengths of young-of-year were reported by various authors to beabout 80-181 mm; age-l, 122-230 mm; age-2,.215-290 mm; and age-3, 275 mm.Relatively few spot are over 3 years old. Their diet includes benthic fauna whichvaries with location. Spot-may be eaten by a variety of predators, includingstriped bass.

Spot occur at temperatures ranging from 8-31 °C and at salinities of 0-66 ppt.They were shown to increase their oxygen consumption with weight, swimming speed andactivity. They appear to be more efficient consumers of oxygen than some majorestuarine species, such as the striped bass and white perch.

17. Docurrafrt Analysis a. Descrptors

Fish FisheriesGrowth Feeding HabitsSalinity Life CycleTemperature Oxygen

b. Idantifier/Opon-Ended Toms

Leiostomus xanthurusSpotHabitat requirements

c. COSATI Fold/Gmuo

I& AaIllability ISttairrnt 19. Security Class (This R* M 21. No. o rdUnclassified 13

Unl imi ted Distribution •so: ecuit class rri.,ra) 2L-ric

Unclassified(See ANSI-MI• 09-TIONAL FORM" 272 (4-7

tVsimety NTIS-3S)

Oalsormitef at Comelwnerc

. -t I . .

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