THE EFFECTS OF SILTATION ON RECRUITMENT OF SPINY LOBSTERS,PANULIRUS ARGUS

WILLIAM F. HERRNKIND,' MARK J. BUTLER IV,' AND

RICHARD A. TANKERSLEy2

ABSTRACT

Several surveys in the Florida Keys indicated fewer juvenile spiny lobsters, Panullrus argus, in anarea where their primary habitat, stands of benthic algae Laurencia spp., was heavily silted ascompared with similar, less silted habitat. We tested several hypotheses explaining this relationship:1) planktonic postlarvallobster abundances are lower in the silted area, 2) siltation of algae impedespostlarval settlement or subsequent juvenile habitat selection, or 3) siltation increases mortality atthe time of metamorphosis. We also compared the time-to-metamorphosis for settling pueruli withinsilted and nonsilted algae, analyzed the physical character of algal silt in low-silt and h,gh-slltregions and measured the abundances of epifauna constituting prey ofjuvenile spiny lobsters. Plank­tonic postlarval abundances were substantially higher in the high-silt area thus rejecting hypothe­sis 1. Likewise, results from laboratory experiments testing the effect of algal siltation on postlarvaltime-to-metamorphosis and early postsettlement survival showed no short-term Increase in mortal­ity. Limited postlarval settlement and avoidance of silted alga: habitats by juveniles, as determinedin substrate choice experiments, probably accounts for the paucity of young spiny lobsters in heavilysilted localities. In addition, although juvenile spiny lobsters are nonselective predators, lower preyavailability in silted algae probably promotes transciency which, in tum, causes increased mortalityby predation while juveniles are exposed. Large-scale siltation exacerbated by human activity mustbe viewed as potentially deleterious to spiny lobster recruitment.

The western Atlantic or Florida spiny lobster,Panulirus argus, is the focus of an intense com­mercial and recreational fishery in south Florida,particularly the Florida Keys. Besides severefishing pressure, spiny lobster populations aresubject to a variety of other factors that poten­tially limit population size. For example, habitatdegradation, like that resulting from chronic sil­tation, may affect not only adult lobsters but thepostlarval settlement stage as well. During 1983and 1984 we sampled numerous sites in a regionof about 40 km2 east of Big Pine Key which waschronically heavily silted and held low numbersof newly settled spiny lobsters despite extensivebenthic algal growth typical of settlement habi­tat, We hypothesized that postlarval spiny lob­sters either do not settle in silted habitat or settlethere but do not survive, In either case, we sup­posed that the heavy siltation reduced the carry­ing capacity of otherwise suitable habitat, poten­tially reducing regional recruitment wheresiltation is widespread.

lDepartment of Biological Science, The Florida State Univer­sity, Tallahassee, FL 32306-3050.

2Department of Biological Science, The Florida State Univer­sity, Tallahassee, FL; present address: Department of Biology,Wake Forest University, Winston-Salem, NC 27109.

Manuscript accepted February 1988.FISHERY BULLETIN: VOL. 86, NO.2, 1988.

Sediment particle size, composition, and stabil­ity influence larval settlement in a variety ofmarine benthic invertebrates (Crisp 1974, 1976;Gray 1974; Rhoads 1974; Pearson and Rosenberg1978). For example, heavy siltation and sedimentinstability, created by natural biogenic rework­ing of the substrate and subsequent resuspensionof sediments by turbulence reduces the abun­dance of suspension feeding infauna (Rhoads andYoung 1971; Aller and Dodge 1974). In addition,siltation from human activities (e.g., dredging,shoreline development, boat traffic, etc.) can de­grade benthic community structure via anaero­biosis, direct burial, toxic poisoning, or increasedturbidity (Morton 1977; Allen and Hardy 1980;Jones and Candy 1981; Cortes and Risk 1985),Most available information concerns sessile or in­faunal species, but little information exists formobile, epibenthic forms (Pearson and Rosenberg1978). Although the habitat selection and bur­rowing behavior of some shrimps and juvenileclawed-lobsters has been investigated in relationto substrate character (Ruello 1973; Howard andBennett 1979; Aziz and Greenwood 1982; Boteroand Atema 1982; Pottle and Elner 1982; Roach1983; Herrnkind and Butler 1986), we know of noresearch describing the effect of siltation on deca-

331

re5:eaJrch fi on the im-r po :tlarvae and

early benthic juvenil , ilia are morpho-logically and behaviorally distinct from adul .

Late ge P. argus phyllo me larvae drift; inth oceanic plankton for ~9 months after hatch­ing and metamorpho offshore into nonfeedingpueruli (po tlarvae) that wim in hore and e Iein benthic vegetation ( arx 19 6). e Iy ettledpueruli metamorpho into cryptically coloredbenthic juvenile in tars after about one we k.Pueruli preferentially ettle in highly architec­tured benthic algal emblage where ub ­quent urvival and growth depend upon availableprey and phy ical refuge from predator<Herrnkind and Butler 19 6). Ubiquitous, widelydistributed tands of bushy red alga ,Laurenciaspp., provide these e ential conditions and prob­ably serve as the mo t important regional ettle­ment and nursery habitat for juvenile piny lob-ters ( arx and Herrnkind 19 5a, b; Herrnkind

and Butler 1986; arx 19 6). The early instarsremain within the algae for everal month untilattaining about 20 mm carapace length ( L)(Andree 1981; Marx and Herrnkind 1985a) whenthey begin to occupy crevice in rubble or underponges, coral, and expo ed eagra rhizome

rna . In Florida, po tlarval ettlement i year­round with vernal, autumnal, newmoon, and oc­c ionally aperiodic peak (Little 1977; Little and

ilano 19 0; Marx 1986). The patial pattern ofsettlement i poorly known although new recruitsare widely dispersed within algal habitats; diverurvey have yielded timate ofone juvenile p r

36 m2 of profu e algal growth ( arx and Herrn­kind 19 5al. Yet becau po tlarvae ttle con­tlnUOU Iy and juvenile grow rapidly; a inglehectare of the above habitat i stimated to nur­ture about 1,000 piny lob te annually (and Herrnkind 19 5a; 19 6). Ther i nocompelling evidence ugg ting that benthic. g lob Immigrate into lorid a fromolh r Carib an •al hough th ir pII rv pr urn bly do (yon 19 ;19 l. cruitment i thu primarily limi d 0

po tlarv 1influx. Th refo ,pr cis kno 1 dg 0

th facto influencing po tlarval ntnd ruitmo lit i niltomana l7'i"",th..

in n IV Florida pin 10 r fiH port on udi und

i th im 0 thon pin Iabund

p

2

HERRNKIND ET AL.: RECRUITMENT OF SPINY LOBSTERS

Florida Keys

Gulfof

Mexico

~~WFOUNDHARBOR KEYS

FLORIDA

INAME

KjY

I BAHIAHONDA

I~KEY

FIGURE i.-Map of field sites in the middle and lower Keys, Monroe County, FL, U.S.A. Insets provide more detail of the areassurrounding our field sites (e). Diagonal lines depict approximate extent of the heavily silted area we surveyed.

of sieves (500 )..I., 250 )..I., and 63 )..I.; U.s. StandardSieve Series), but only the two smallest size frac­tions were retained because subsamples >500 )..I.

consisted entirely of shell and algae fragments.Silt samples were dried for 48 hours at 100°C andthen weighed. The amount of algal-entrained siltat the two sites was compared using a two-samplet-test. Organic weight of the silt was derived bydigesting three silt samples in 30% hydrogen per­oxide for 1 week, then oven drying the remainingsilt at 60°C for 48 hours (Cortes and Risk 1985).The fraction of carbonates in the silts was deter­mined by dissolving the three samples in 5% hy-

drochloric acid for 1 week, then drying the sam­ples as above (Cortes and Risk 1985). Percentorganics and carbonates (by weight) in the silts atthe two sites were compared in two-sample t -testson arcsin transformed data.

We counted the number of epifaunal prey insilted and unsilted clumps to determine the possi­ble influence of siltation on juvenile spiny lobsterfood abundance. The reported estimates of preyabundance are means of two separate counts perclump; 5 clumps per treatment were processed.The volume of each Laurencia clump was deter­mined by water displacement, and all silt load

333

and prey abundance estimates standardized byclump volume. Prey abundance data were ana­lyzed using a two-way fixed-effects ANOVA onlog transformed data and Bonferroni pairwisemultiple comparisons.

Habitat Selection/Settling Experiments

We tested postlarval settlement and juvenilehabitat selection in laboratory experiments usingclumps of Laurencia spp. with high- and low-siltloads I referred to hereafter as silted and un­~ilted); the null hypothesis being equal selectionof both habitats. Experiments were conducted infourteen 75.7 L aquaria with subgravel filtersand circulating current of 3 cm s 1. Light wasprovided by skylights and fluorescent lights witha photoperiod of approximately 14L:I0D. Two 20em diameter algal clumps, one silted and one un­silted, were situated 25 cm apart at opposite endsof each aquarium and at least 5 cm from aquar­ium walls. The number of natural prey in bothsilted and unsilted clumps far exceeded the num­ber eaten daily by a juvenile. To further controlfood availability in experiments with juvenileswe added equal amounts (10 mg) of Tetramin 3

fish food to each clump, providing an overabun­dance of food available ad libitum. If juvenileschose one type of algal clump over the other, thentheir selectIOn was most likely based on the pres­ence or absence of silt, because food abundanceand quality were similar, if not strictly identical,in both types of algal clumps. Pueruli neither feednor respond to the differential abundance of po­tl:'ntial prey (Herrnkind and Butler 1986l. Siltedalgae was collected from the No Name Key site\see "l:'ction on Algal Silt Content and 'Prey Con­umt): unsilted algae was collected just offshore ofthe Sl:'a World Marine Science and Conservation('"r.tl'r on Long Key. Fresh algal clumps wereu"ed in each experimental replicate. An experi­ment was initiated by introducing a singlepuerulus or juvenile spiny lobster to the center ofan aquarium through a 5 cm diameter PVC pipe.Once a spiny lobster settled to the substrate, thepipe was slowly withdrawn allowing the lobsterto move freely about the aquarium. This tech­nique prevented "tailflipping" by lobsters and fa­cilitated active selection of habitats. Twenty-fourhours later we located the lobsters and recordedtheir positions, as in previous experiments

3Reference to trade names does not imply endorsement by theNatIOnal Manne Fisheries Service, NOAA.

334

FISHERY BULLETIN: VOL. 86, NO.2

<Herrnkind and Butler 1986). Fourteen spiny lob­sters were tested on day 1, 14 more on day 2, andso on until our stock of animals was depleted.Each lobster was used only once. All pueruli werecollected on the incoming tide from the planktonin interisland channels. Pueruli were eithertested immediately or allowed to metamorphosefor later use in experiments requiring juveniles.Data were analyzed with log-linear (}{)odness-of­fit tests.

Metamorphosis Experiment

The effect of siltation on the survival and time­to-metamorphosis of pueruli was tested experi­mentally in an outdoor, flow-through seawatersystem. One freshly collected puerulus was placedin each of 46 seawater-filled 1 L plastic beakers,23 containing 5 cm diameter clumps of unsiltedalgae and the other 23 an equal amount of siltedalgae. Each container was independently sup­plied with flowing, filtered seawater. Algalclumps were replaced daily. Pueruli do not feedand their habitat selection operates independentof food availability <Herrnkind and Butler 1986>,thus no food was added to the containers. Sea­water temperature in the beakers remained be­tween 26° and 28°C; photoperiod was approxi­mately 14L:10D. Pueruli were monitored dailyand their survival and time-to-metamorphosisrecorded.

Pueruli were collected as transparent postlar­vae from the plankton in interisland channelswhich concentrate oceanic postlarvae as theymove into Florida Bay nursery areas. Time-to­metamorphosis values represent the elapsed time(in days) from puerulus collection until metamor­phosis into the first benthic stage. Values arelikely to differ among collections as different co­horts of pueruli arrive inshore. There are cur­rently no techniques available to determine theactual age of pueruli (i.e., time since metamor­phosis from the phyllosoma stage), but estimatesof duration of the puerulus stage range from2 weeks to 1 month (Lyons 1980; Calinski andLyons 1983). Differences in time-to­metamorphosis between the two treatments wereanalyzed via a two-sample t -test.

Juvenile Spiny Lobster Prey SelectionExperiments

Laboratory experiments were conducted to de­termine juvenile spiny lobster prey preference

HERRNKIND ET AL.: RECRUITMENT OF SPINY LOBSTERS

TABlE 1.-Relative prey availabilities (A) and predator usage (U)values (percentages) in the three juvenile spiny lobster prey selec­tion experiments. N = 15 lobsters per experiment. F-values calcu­lated from Johnson (1980) indicate whether prey choice dlHeredsignificantly from random in each trial: none of the tests were signif·icant at P = 0.05.

and rate of consumption of algal epifauna. Preywere obtained by rinsing large clumps of Lauren­cia through a 100 ~ sieve. Prey included smallgastropods, amphipods, isopods, and ostracodsranging in size from 1 to 9 mm (Marx and Herrn­kind 1985a). Prey were individually counted andplaced in 1 L plastic beakers containing 750 mL ofseawater. One starved (24-h) juvenile lobster (6­8 mm CL) was introduced to each container, al­lowed to feed for 12 hours, and was then removed;the remaining prey were counted. Fifteen spinylobsters were tested in each experiment; each lob­ster was used once. Three experiments were con­ducted using different prey combinations (Table1), but the total number of prey available re­mained similar and exceeded the amount a singlelobster could consume in 12 hours. Electivity in­dices calculated for each experiment were used inmultiple comparison tests to determine whetherjuvenile spiny lobsters fed preferentially or ran­domly (Johnson 1980).

Experiment

2

Prey type A U A U

GastropodaTricolia sp. 43.5 61.5 71.4 83.0Banillaria spp. 8.7 1.0 4.3 02Tegula spp. 6.5 0.0Atys spp. 14.3 7.2

Amphipoda 32.6 33.9 10.0 9.6lsopodaCopepodaOstracodaDecapoda 8.3 3.6

F-values 0.46 0.40df 4.11 3.14

3A U

58.0 54.5

7.0 7.117.4 20.011.6 13.16.0 5.3

0.094.11

Silt recovered from the algal clumps waslargely calcareous and formed a coheSive castaround the algal filaments. ClassifYIn~ al~al­

bound silts by particle size would yield irrelevantvalues because sieving caused fra~entation ofaggregated particles. Therefore we report on lythe total dry weight of the silts. Algae at :--;0Name Key carried a higher silt load than algat· atBurnt Point (~ = 125 vs. 65 g L algae. respt'C­tively; t = 2.90. df = 18. P r 0.011. Slit at :"-10Name Key was characterized as 12.5 • 74"; or­ganic and 28.1:= 27.6'1 carbonate hy weight.whereas Burnt Point silt was 16.9 - 1.06'; or­ganic and 66.3 := 14.5~; carbonate (means· 1 :'()I.

There was no significant difference In slit compo­sition between sites (organics: t :·0.10\:3. df 4.P >0.05; carbonates: t = 1.97. df~ 4. P . (UI!) I.

although sample sizes at each site were small andsample variance substantial. Algae at both Sllt·S

contained primarily gastropods. amphipods. andisopods. although significantly more gastropodsand echinoderms occupied unsilted clumps(Fig. 2. Table 3; P < 0.05 in Bonferroni pairwlst·multiple comparisons).

Significantly more pueruli settled in unslllt'dalgal clumps than in silted clumps during lahora­tory settlement choice experiments 1:38 \'s 11. n'·spectively; G = 15.72, P < 0.0011. Juvenile Sptn~·

lobsters responded similarly in the hahltat splt·c­tion experiment (54 vs. 24; G = 11.7R. p. O.IHlIl

We excluded the open sand habitat in aquariafrom our analysis because 11 juvenile Sptn\ Inh·sters are never found residing on open sand 1:1 t ht,field. presumably due to a lack of food and rt'fugl'

TABLE 2-(A) Posllarvallobster abundances at Silled and unsiltedFlonda Bay study areas Posllarval catch per un,t e"o<1 rCPUE I

was estimated from Wilham collector catches (B) Juvenile lob·ster (8-20 mm CL) abundances at the two study sites ,n 1985 anaadjacent areas sampled dunng 1983 and 1984 Juvenile CPUEwas estimated via diver surveys

RESULTSA POSTLARVAL ABUNDANCE

CPUE'

'CPUE . no 01 (lOStIarvae no 01 collectorsno 01 clayS be_ c:oIIec1JOnS

No Name Key (1983-85) SIltedBurnt POint (1983-85) unSlned

B. JUVENILE ABUNDANCES

no Of Iobslen OOileC1edno of~nours

0'5o '0

282'0

DIVinghours

008 032001 005

June July

Descnptoon

SiltedunSilted

Descnphon

LocatIOn

2(;PUE

Location

No Name KeyBurnt POint

Postlarvae were more abundant on collectors atthe silted site than at the unsilted site. Diversurveys revealed that higher numbers of algal­dwelling juveniles «20 mm CLl resided at theunsilted site despite greater influx of pueruli intothe silted area (Table 2). Only one juvenile spinylob ter collected at the silted site was <20 mmCL, most were considerably larger (25-35 mmCLl than those at the unsilted site, and some werepossibly large enough to have immigrated therefrom acijacent unsilted areas.

FISHERY BULLETIN: VOL. 86, NO.2

ECHINO*DEC AISOAMPHIGASTRO* OSTRA

I1200

o NO NAME KEY (silted)

1000• BURNT POINT (unsilted)

u..0...J 800......en...J<C~ 6000>0z 400u..0a:

200wCD~~

Z

FIGURE 2.-Abundances Ix :!: 1 SEl of the six most common prey found in algal clumps atthe silted 0 Name Key and unsilted Burnt Point sites. Five clumps were collected at eachsite. Values are standardized by clump volume. Asterisks denote significant difference inBonferroni multiple comparison tests IP = 0.05l. Abbreviation key: GASTROpod, OSTRAcod,AMPHlpod. Isopod. DECApod. ECHINOderm.

TABLE 3.-Two-way fixed-effects ANOVA testing for differences inthe total number of Individuals among six prey categories (seeTable 1) at two sites. one silted (No Name Key) and one unsilted(Burnt POint) Data were log transformed.

Source df SS F P

Site 1 0.841 18.78 0.001Prey type 5 6.242 27.89 0.001Site X prey type 5 0.847 3.78 0.006Error 48 2.149

(Marx and Herrnkind 1985b; Herrnkind and But­ler 1986). 2) most spiny lobsters recovered fromopen sand were actually in corners, indicatingedge-seeking behavior rather than selection forsand per se, and 3) only 10.6% of 142 spiny lob­sters tested were found on sand even though itconstituted 68% of the exposed substrate inaquaria. Silt had no effect on puerulus survivalthrough metamorphosis to the first benthic instar(13% vs. 9% mortality in silted and unsiltedalgae, respectively), or time-to-metamorphosis(Fig. 3; t = 0.37, P > 0.05).

The total number of prey items consumed in thejuvenile prey selection experiments ranged from19 to 57 prey per lobster per 12 hours. Juvenilesfed randomly from the three different prey combi­nations and frequencies offered to them (Table 1).

"zen 200:::ca.a:0~ 10~W~

dz 0

0 1 2 3 4 5 6

DAYS

FIGURE 3.-Cumulative number of spiny lobster postlarvaemetamorphosing as a function of time in one of two treatments:silted algae (Laurencia spp.J or unsilted algae. Twenty-threepostlarvae were tested in each treatment; two postlarvae died inthe unsilted treatment and three in the silted treatment.

DISCUSSION

The relative paucity of newly settled spiny lob­sters in the heavily silted region around No NameKey over a 3-yr period indicates that low recruit­ment to benthic habitat is typical there. The ab­sence of juveniles was apparently not due to a

336

HERRNKIND ET AL.: RECRUITMENT OF SPINY LOBSTERS

lack of postlarval influx, which was higher thanthat at the unsilted Burnt Point site, but insteadto low rates ofpostlarval settlement. Results fromour habitat selection experiments support thishypothesis because settlement was significantlylower in silted algal clumps than in unsiltedclumps. Previous studies showed that postlarvaeselectively settled in highly architectured materi­als, like algal clumps (Herrnkind and Butler1986). Thus, heavy silt covering an otherwise pre­ferred habitat either masks the stimuli triggeringsettlement or contains stimuli that elicit rejectionby pueruli. This question remains for furtherstudy. We cannot conclusively ascertain from ourlaboratory experiments the mechanisms govern­ing habitat choice in the field where silted andunsilted habitats may not be adjacent, as theywere in our aquaria. Yet for many species withplanktonic larvae, these kinds of experiments,coupled with field observations of more generalpatterns of behavior and abundance, providevaluable insights into natural processes (Sulkin1986).

Twenty percent of the pueruli we tested in lab­oratory tanks settled in silted clumps despite thegeneral rejection of this habitat. Pueruli settlingin silted algae probably metamorphose normally

I into the first benthic instar, as indicated by the,equivalent time-to-metamorphosis and early post­settlement survival in both silt levels tested.However, subsequent residency by juveniles pre­sumably is limited, given their great mobility andpreference for unsilted algae with high food levels(Marx and Herrnkind 1985b; Herrnkind and But­ler 1986). We found that prey abundances weresignificantly lower in silted algae. Thus, even ifpueruli settle in the silted habitat the subsequentjuveniles may leave to obtain adequate food. Fre­quent interclump movement by juvenile spinylobsters, searching either for food or unsiltedhabitat, would predictably result in increasedpredatory mortality. Susceptibility to predationis much greater for juveniles in the open, than itis for individuals amidst algal clumps or denseseagrass (Herrnkind and Butler 1986). Thus, ju­venile' residency patterns and susceptibility topredation may, in addition to locally low settle­ment, contribute to the paucity of lobsters in thesilted habitat.

The algal-bound silt load at No Name Key wasroughly twice that at Burnt Point where spinylobster recruitment was considerable. Our cur­sory surveys from Key Largo to Boca Chica Keyindicate that similar silt levels are common,

though geographically variable in Florida Bay.Benthic algae, including Laurencia spp., serve assediment traps (Scoffin 1970) and demonstrate aremarkable resistance to siltation, growing pro­fusely even in heavily silted areas. Silt in theseareas is primarily calcareous, most of it probablya byproduct of sediment processing by depositfeeding shrimp (particularly Callianassa l, an­nelids, and sea cucumbers.

We did not evaluate the geographic extent ofsiltation relative to spiny lobster settlement inFlorida Bay. However, the demonstrated aver­sion to settling in naturally silted algae, charac­teristic of the region around No Name Key,strongly suggests that low postlarval recruitmentand juvenile abundances would occur in similarconditions elsewhere. The sparse juvenile popula­tion at our silted site, one-tenth that of the un­silted site, suggests deleterious impact of highchronic silt levels in areas of potential recruit­ment. Human activities also cause siltation (Mor­ton 1977; Allen and Hardy 1980). We noted thatalgal stands adjacent to heavily trafficked boatchannels typically were more heavily silted thanadjacent areas. We suspect the effect of manmadesiltation to be similar to that from natural causes.Although it is now generally accepted that Flor­ida Bay shallows serve as the main nurserygrounds for the south Florida spiny lobster popu­lation (Marx 1986), the regional distribution ofsettlement and early juvenile habitation remainsto be mapped. Future wide-area surveys by con­cerned researchers and agencies should includesampling of new spiny lobster recruits as well assilt levels. Meanwhile, sizable human activitiessuch as channel construction, dredging, spoildumping, coastal development, and mineral min­ing must be viewed as potentially deleterious tospiny lobster recruitment.

ACKNOWLEDGMENTS

We thank the Sea World Center for Marine Sci­ence and Conservation on Long Key, FL, for logis­tical support and the use of their facilities. JohnHunt and Jim Marx of the Florida Department ofNatural Resources Marine Research Laboratoryin Marathon provided field assistance and helpfuladvice throughout the project. Comments byP. Greenwood, D. Wilber, and two anonymous re­viewers substantially improved the manuscript.This research was supported by a Sea Grantaward (RJLR-B-16) to W. F. Herrnkind. Addi­tional support was provided M. J. Butler via

337

Marine Science Fellowships from the AylesworthFoundation and the International Women's Fish­ing Association (lWFA).

LITERATURE CITED

AU.EN K D ANIl J W HAROV

19HO Impacts of navIgatIOnal dredlnng on fish andwildlIfe: a lIterature revIew US FIsh Wild. Serv., BIOI.Sl'n' Program FWS OBS-8007, III p

AIHR R C \NIl R E DOO(;E

1974 Animal-sediment relations 10 a tropIcal lagoon,DlscoH'ry Bay, JamaIca J Mar Res :12209-232.

A"1llflEE S W19H 1 Locomotory actIvIty patterns and food Items of ben­

thIC post larval spmy lobsters, Panuhrus argus. MSThe",,,, Flonda State UnIversIty. Tallahassee. FL. 50 p.

AZIZ K A \SIl ,J G GflEENWOOIl

19H2 Responsl' of Juvenile Melap<'nal'us h"nnPllae Racek& Doll 19751 Decapoda' Penaeldael to sedIments of dlffer­109 particle sIze. Crustaceana 4:3:121-126.

BOTERO. L. ASf) J ATE~A

19H2. BehaVIOr and substrate selection dunng larval set­t1mg 10 the lobster Homar"s amerlcanus ,1. Crust.BIOI 259-69.

CALINSKI. M D AND W G LVONS

1983. SWlmmmg behaVIOr of the puerulus of the spmylobster Panuhrus argus ILatnelle, 18041 I Crustacea: Pal­mundael J Crust. BIOI. 3329 335

COflTES. J NAND M J RISK

19H5 A reef under SIltation stress Cahulta, CostaRIca Bull Mar. Sc.. 36339-356

CRISP D J1974 Factors mfluennng the settlement of mannI' mver­

tebrate larvae In P T Grant and A M MackIe ledltorl,Chemoreception 10 manne organIsms, p. 177-265Acad Pre"s, .Y.

1976 Settlement responses 10 manne organIsms. InR C ~eweilledltorl, AdaptatIon to environment. essayson th .. phYSIology of manne animals, p. 83-124.Rutterworths, Lond.

GR,\Y,J S1974 Animal-sediment relationships. Oceanogr Mar.

Bioi Annu. Rev. 12223-261.HEflf{SKlsn. W F. AND M J BUTLER IV

19H6 Factors regulating postlarval settlement and juve­nile microhabItat use by spiny lobsters Panulrrusargus Mar Ecol Prog. Ser. 34:23-30.

111,\\ .\flO. A E. AND D B BENNETI.

1979 The substrate preference and burrowing behavior ofJuvenile lobsters IHomarus gammarus (L.)). J. Nat.Hist. 13:433-438.

JOHNSON.D H

1980. The comparison of usage and availability measure­ments for evaluating resource preference. Ecology6165-71

JONES. G . AND S CANDV

1981 Effects of dredging on the macrabenthic infauna ofBotany Bay. Aust. J. Mar. Freshwater Res. 32:379-398.

UTILE. E J1977. Observations on recruitment of postlarval spiny

lobsters, Panulirus argus, to the South Florida coast.

338

FISHERY BULLETIN: VOL. 86, NO.2

Fla, Mar. Res. Publ. No. 29, 35 p.UTILE. E J ,JR. AND G R MILANO

1980. Techniques to monitor recruitment of postlarvalspiny lobsters. Panulirus argus, to the FloridaKeys. Fla. Mar. Res. Publ. No. 37. 16 p.

LVONS, W G

1980 Possible sources of FlorIda's spiny lobster popula­t,on Proc. Gulf Canbb. Fish. Inst. 33:253-266.

MARX.J M

1986. RecruItment and settlement ofspiny lobster pueruli10 south Flonda. Can. J. Fish. Aquat. Sci. 43:2221­2227.

MARX. J M. AND W F HERRNKIND

1985a. Macroalgae (Rhodophyta: LaurencUJ spp.J as ahabitat for young JuvenIle spiny lobsters, Panullrusargus Bull Mar. Sci. 36:423-431.

1985b. Factors regulating microhabitat use by young ju­venile spmy lobsters, Panullrus argus: food and shel­ter J Crust. BioI. 5:650-657.

MORTON, J W.

1977. Ecological effects of dredging and dredge spoil dis­posal: a literature revIew. U.S. Fish Wild. Serv. Tech.Pap. No. 94, Wash., D.C.

PEARSON. T H . AND R ROSENBERG

1978 Macrobenthlc succession in relation to organic en­nchment and pollution of the marine environ­ment Oceanogr Mar. BioI. Annu. Rev. 16:229-311.

POITLE. R A. AND R W ELNER

1982 Substrate preference behaVIor ofJuvenile Americanlobsters, Homnrus a~rtcanus, in gravel and silt-claysedIments. Can. J. Fish. Aquat. Sci. 39:928-932.

RHOADS. DC

1974 OrganIsm-se<!Jment relations on the muddyseafloor Oceanogr. Mar. BIOI. Annu. Rev. 12:263-300.

RHOADS. D C. AND D KYOUNG

1971 AnImal-sediment relations in Cape Cod Bay, Mas­sachusetts. II. Reworking by MolpadUJ oalltu:aIHolothuroideal. J. Mar. BioI. 11:266-261.

ROACH.S G1983 Survivorship, growth, and behavior of juvenile lob­

sters Homnrus a~ru:anusMilne-Edwards in controlledenvironments in nature. ova Scotia Dep. Fish. Mar.Res. Tech. Rep. Ser. 83-02, 60 p.

RUELLO. N V1973. Burrowing, feeding, and spatial distribution of the

school prawn Metapena.eus mncleayi lHaowell) in theHunter region (Australia). J. Exp. Mar. BioI. Ecol.13:189-206.

SCOFFIN, T P.

1970. The trapping and binding ofsubtidal carbonate sed­iments by marine vegetation in Bimini Lagoon, Ba­hamas. J. Sediment Petrol. 40:249-273.

SULKIN,S D .

1986. Application of laboratory studies of larval behaviorto fisheries problems. Can. J. Fish. Aquat. Sci. 11:2184­2188.

WITHAM. R., R. M. INGLE, AND H. W. SIMS JR.

1964. Notes on postlarvae ofPanulirus argus. Q. J_ Fla.Acad. Sci 27:289-297_

WITHAM, R, R. M INGLE, AND E. A. JOYCE JR_

1968. Physiological and ecological studies of Panulirusargus from the St. Lucie estuary. FL Board Conserv.Tech. Ser. 53:1-31.