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BULLETIN OF MARINE SCIENCE 56(1) 268-282 1995

BATHYMETRIC DISTRIBUTION AND POPULATION SIZESTRUCTURE OF PAXILLOSID SEASTARS(ECHINODERMATA) IN THE CABO FRIOUPWELLING ECOSYSTEM OF BRAZIL

Carlos Renata Rezende Ventura and Flavia da Costa Fernandes

ABSTRACTSampling of paxilJosid seastars by 20-min trawls was made monthly at depths of 30 45

and 60 m from January 1986 to December 1988 Bottom water and sediments were ana-lyzed Four thousand one hundred twenty-one individuals comprising five species were col-lected Astropecten cingulatus (546) A brasiliensis (264) Luidia ludwigi scotti(189) L altemata laquoI ) and Tethyaster vestitus laquo1 )Astropecten brasiliensis occurredprimarily at 30 m (from very well to well-sorted medium sand) and 45 m (from well tomoderately-well sortedmedium sand) while A cingulatus and L ludwigi scotti were mostcommon at 45 m and 60 m (from well to moderately-well sorted fine sand) Differences insize-frequency distributions of A brasiliensis were recorded at 30 and 45 m depths Popu-lation densities were higher and body size smaller (R = 4-5 cm) at the shallower depth (30m) At deeper depth (45 m) individuals were larger (R = 7-10 cm) and coexisted with otherspecies of seastars Astropecten cingulatus showed similar size-frequency distributions at both45 and 60 m depths (R = 4 cm) No species showed a pattern of seasonal variation in densityHighest densities occurred when sea water temperatures were lower than 18degC suggestingsome relation with periods of upwelling Differences in population size structures of seastarssuggest that the recruitment rate is independent of local densities

The distribution of different species may be studied on several scales Thelarger-scale approach allows a biogeographic analysis based on patterns of distri-bution of species and genera The smaller-scale approach gives details of spatialvariations in density with and between species It is important to quantify patternsof distribution and to identify the processes that determine such patterns (Thrush1991) In both approaches species distribution relates to the nature of the abioticenvironment The small-scale spatial distribution may also be affected by biolog-ical interactions Both intraspecific and interspecific interactions as well as den-sity-dependent factors influence spatial distribution (Mukai et aI 1986 Thrush1991)

Distribution data of species are also useful for determination of adaptive zonesof a supraspecific taxon (Van Valen 1971 Blake 1990) Paxillosid asteroids havea distinct adaptive zone They live in shallow to deep environments feeding onlarge prey and small particles from substrate (Jangoux 1982 Blake 1990) Mostpaxillosidans lack suckered disks on the tube feet and are apparently limited tosoft substrata (Blake 1990) Paxillosid adaptive zones seem to be well definedbut further details of depth distribution and population size structure of sympatricspecies are necessary to provide background information for a better understand-ing of the group

Studies on population biology of seastars along the coast of Brazil have focusedprimarily on taxonomy and systematics (Tommasi 1958 1961 1970 1974 1985Bernasconi 1957 Brito ]968 Manso 1989) Only a few studies have examinedthe relationship between the distribution or abundance of seastars and environ-mental characteristics of sediment or bottom water (Carrera-Rodriguez and Tom-masi 1977 Manso 1989) However the seastars are an ecologically importantand numerically dominant group in soft-bottom marine communities of Brazil

268

VENTURA AND FERNANDES BRAZILIAN PAXILLOSID SEASTARS 269

The purpose of this study was to describe the bathymetric distribution abundanceand population size structure of seastars from an upwelling region of the CaboFrio continental shelf These aspects are interpreted in the light of sea watersalinity and temperature data as well as information on sediment grain size andorganic content

STUDY AREAThe Cabo Frio region (23degS 42degW) is in the central-southern littoral zone of Brazil The shore line

bends inwards abruptly from N-S to E-W and the continental shelf becomes narrow Consequently100 and 200 m depths occur near the coast (Valentin 1984) (Fig I) During spring-summer (Septem-ber to March) the prevailing E-NE winds and Coriolis effects cause upwelling of subtropical waters(South Atlantic Central Water SACW) resulting in temperatures lower than 18degC salinities lowerthan 360 and nitrate concentration higher than 10 mmolmiddotm-3 (Thomsen 1962 Valentin et aI 1987Rodriguez et aI 1992) Downwelling occurs when S-SW winds cause the replacement of SACWwith tropical warmer water (Brazil Current BC and Coastal Water CW) The upwelling cycle isinterrupted most frequently during winter (June to August) (Valentin 1984 Valentin et aI 1987Rodriguez et aI 1992)

MATERIALS AND METHODS

Seastars were sampled by conducting one 20-min trawl monthly along Maambaba Beach Arraialdo Cabo RJ (22deg57S 23deg00S 47deg07W 42deg11 W) at depths of 3045 and 60 m from January 1986to December 1988 The otter-trawl was equipped with a 12-m footrope and cod-end mesh with a sizeof 25 mm All trawls were conducted in daylight (10 AM to 3 PM) at a speed of approximately 30kn The area sampled in each trawl was approximately 2620 m2 as estimated by methods of Alverson(1971) and Pauly (1984) Bottom sea water was sampled with a Nansen bottle at six oceanographicstations (Fig I) Water temperature was measured at each station using a reversing thermometerSalinity was measured with a Beckman induction salinometer and dissolved oxygen by the Winklermethod (Strickland and Parsons 1972)

Sediment samples were collected using a Van- Veen grab (01 m2) at each depth from April 1986to February 1987 Granulometrical sediment fractions were determined according to Ingram (1971)The size-distribution of grains was expressed in dry weight and statistical grain parameters werecalculated according to Buchanan (1984) A portion of the sediment samples (100 g) was used formeasuring the proportion of calcium carbonate and organic carbon The former was expressed aspercent weight loss after HCI treatment and the latter by chromic acid organic matter oxidation bothon a dry weight basis (Buchanan 1984)

Abundance of seas tars was determined considering the number of individuals sampled per trawlSize-distributions of seastars were estimated by measuring the radius (R) (the distance from the

mouth to the longest arm tip 1 mm accuracy) Bathymetric differences in the size-distributions ofseastars and in the bottom sea water and sediment parameters were statistically analyzed using a Chi-square test and Mann-Whitney and Kruskal-WaIlis rank tests respectively (Siegel 1975 Sokal andRohlf 1981) The Thkeys test for non-parametric randomized block analysis of variance was calcu-lated following Kruskal-Wallis Analysis (Zar 1984)

After measurement seastars were fixed in 5 formaldehyde and preserved in 70 alcohol Allspecies collected were identified according to Tommasi (1970) Clark (1982) and Clark and Downey(1992) Specimens were deposited in the Echinodermata collection of the Museu Nacional (Univer-sidade Federal do Rio de Janeiro)

RESULTS

Abiotic Features of Bottom Water and Sediment-Bottom sea water temperatureranged from 128degC (November 1988 at 45 m) to 242degC (May 1988 at 30 m)Of all samples 64 were collected in cold water (lower than 18degC) mostlyoccurring in summer (33) and spring (29) Low sea water temperatures wereless frequent in autumn (22) and winter (16) Warmer sea water bottom tem-peratures were recorded more frequently in winter (50) and autumn (34) thanin spring (9) and summer (6) Monthly variations in bottom sea water tem-perature reflect this tendency for colder water to be present during summer andspring (Fig 2) Mean bottom sea water temperatures decreased with increasing

270 BULLETIN OF MARINE SCIENCE VOL 56 NO I 1995

---- -----~--

~ bullbullbullbullbullbullbullbullbullbullbullbull J

- --100 bullbull

N

1-

LAGOON

~lll

2 411mbullbullbullbull _ _ bull- (5middot50 bullI --- -- -~ bullbullbullbullbullbullbullbullbullbull-

-- So 11011I 11

ATLANTIC OCEAN

Figure 1 Map of the Cabo Frio region squared-off area is expanded to indicate details of the studysites Strippled area show where the trawls were taken

depth from 30 to 60 m depth Salinity and dissolved oxygen changed only slight-ly The former ranged from 3430 (November 1988 at 60 m) to 36510 (June1988 at 30 m) and the latter from 354 m1middotliter-I (May 1987 at 60 m) to 662ml-liter-I (September 1988 at 45 m) Mean monthly temperature salinity anddissolved oxygen did not differ significantly (P lt 005 Kruska1-Wallis Analysis)among depths It was possible to identify three distinct water masses in the studyarea South Atlantic Central Water (SACW) laquo18degC and lt3600) Coastal Water(CW) (gt18degC and lt3600) and Brazilian Current Water (BC) (gt18degC andgt3600)

Mean amounts of calcium carbonate organic carbon grain median diameterand inclusive graphic standard deviation of shallow (30 and 45 m) and deep (60

VENTURA AND FERNANDES BRAZILIAN PAXILLOSID SEASTARS

30

- 30 metres --- 45 metres middotmiddot0middot- middotmiddot 60 metres

271

o 26o

~ 22JCOCD 18QE~ 14

10JFMAMJJASONDJFMAMJJASONDJFMAMJJASONDII 1986 I 987 I 988

37- 30 metres -- 45 metres ---- 60 metres

0-(flt 36

35 35

34 JFMAMJJASONDJFMAMJJASONDJFMAMJJASONDI 986 I 987 I 988 I

7

3JFMAMJJASONDJFMAMJJASONDJFMAMJJASONDI 986 I 987 I 1988 I

Months

bullbull(J)

EcCD(J)gtoD92o(f)(f)

o

6

4

-30 metres bull - 45 metres laquo- 60 metrmiddotes

Figure 2_ Monthly variations in sea water temperature salinity and dissolved oxygen at oceanograph-ic stations_


Table 1 Mean values of calcarium (Ca) organic carbon (DC) mean grain size diameters (MGSD)and inclusive graphic standard deviation (IGSD) of sediments

Depths(m) Ca (mgg-) OC() MGSD (phi) IGSD (phi) Classification

30 338 t 132 021 tom 170 t 048 040 t 008 Well-sorted medium sand45 1015 t 553 021 t 001 182 t 058 059 t 022 Moderately well-sorted

medium sand60 1982 t 1036 051 tom 267 t 034 068 t 022 Moderately well-sorted

fine sandbull Wentworth grade classification

m) depths (Table 1) differed significantly (P lt 005 Kruskal-Wallis Analysis)Tukeys test showed that these differences occurred between 30 and 60 m stationsand between 45 and 60 m in all but one parameter (calcium carbonate) The onlydifferences in calcium carbonate levels were recorded between stations 1 (30 m)and 2 (45 m) and stations 5 (45 m) and 6 (60 m) (Fig 1) Shallower depths hadlarger grain sizes as compared to the 60 m depth (Kruskal-Wallis Analysis)Therefore sediments were similar at 30 and 45 m depths where lower values oforganic carbon were detectedBathymetric Distribution and Abundance of Species-A total of 4121 specimenscomprising 5 species were collected from 96 trawls Astropecten cingulatus Slad-en 1889 Astropecten brasiliensis Muller and Troschel 1842 and Luidia ludwigiscotti Bell 1917 were the most frequently collected and abundant species Onlyone specimen of Tethyaster vestitus (Say 1825) and of Luidia alternata (Say1825) were collected during the entire study (Table 2) A cingulatus was the mostnumerous species sampled (546) followed by A brasiliensis (264) and Lludwigi scotti (1895) (Table 2)

The bathymetric distributions of these species showed the same patterns during1986 1987 and 1988 Differences between the observed numerical distributionof seastars according to depths and those expected under a null hypothesis ofrandom distribution were highly significant (Table 3) At 30 m depth A brasilien-sis was the most abundant and frequently collected species (Fig 3 Tables 2 4)At 45 m depth A brasiliensis A cingulatus and L ludwigi scotti coexistedcomprising more similar percentages of the populations than at other depths (Fig3 Tables 2 4 5 6) At 60 m depth A cingulatus and L ludwigi scotti predom-inated but the former was more abundant and the most frequently collected (Fig3 Tables 2 5 6)

Temporal variations in the densities of seastars did not show any seasonality(Fig 3) Nonetheless the greatest densities were recorded when sea water tem-peratures and salinities were lower than 18degC and 3600 respectively (Fig 4)In 1988 the greatest densities of seastars were recorded at 30 45 and 60 m depth(Fig 3 Tables 2 4 5 6)

Size Structure of Seastar Populations-Size-frequency distributions of seastarsshowed variations by depth and year (P lt 005 Mann-Whitney test) (Fig 5Table 7) A brasiliensis showed a similar distribution at 30 m (x plusmn I SO R =599 plusmn 133) and 45 m (x plusmn I SO R = 607 plusmn 149) depths in 1986 Largerindividuals (6-10 em R) were more frequent at 45 m (x plusmn I SO R = 664 plusmn175) in 1987 In 1988 size-frequency distributions were basically bi-modal at30 (x plusmn 1 SO R = 552 plusmn 208) and 45 m (x plusmn 1 SO R = 501 plusmn 257) depthsand significantly different from one another Smaller individuals (1-3 em R) weremore frequent in 1988 A cingulatus populations were composed of smaller in-

VENTURA AND FERNANDES BRAZILIAN PAXILLOSlD SEASTARS 273

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Table 3 Observed and expected (in parentheses) number of individuals of seastar species

DepthSpecies

(m) Period A brasiliensis A cingulaus L ludwig scotli X

30 1986 72 (3181) 13 (5157) 2 (361)45 48 (3876) 57 (6284) 1 (440) P lt 00160 12 (6143) 144 (9959) 12 (558)

30 1987 143 (4564) 11 (7732) 3 (3403)45 146 (10000) 110 (16942) 88 (7457) P lt 00160 2 (14535) 372 (24625) 126 (10839)

30 1988 248 (6271) 1 (14551) 11 (5177)45 406 (172 70) 113 (40072) 197 (14258) P lt om60 11 (42958) 1429 (99677) 341 (35465)

dividuals than other species (reaching only 6 cm R) At 60 m depth where theyoccurred in greatest densities size-frequency distributions revealed a mode atapproximately 4-cm radius (x plusmn 1 SD R = 418 plusmn 081 in 1986 392 plusmn 073in 1987 and 408 plusmn 080 in 1988) At 60 m mean sizes were smaller than at 45m (x plusmn lSD R = 440 plusmn 069 in 1986 454 plusmn l01 in 1987 and 466 plusmn 067in 1988) L ludwigi scotti was the most easily damaged species with many in-dividuals losing arms during trawls Therefore estimating the size-frequency dis-tribution of the population was difficult Size distributions of individuals withentire arms are shown in Figure 5 In 1987 the mode of sizes peaked at 3 emradius at 60 m depth (x plusmn 1 SD R = 368 plusmn 167) A bi-modal size distributionwas recorded at 45 m depth (minor mode about 3 em R and major mode about9 em R x plusmn lSD R = 579 plusmn 266) In 1988 this species was more abundantthan in 1986 and 1987 At 60 m depth the size structure of the population ap-proximated a normal distribution (mode about 5 em R x plusmn 1 SD R = 558 plusmn183) and at 45 m depth (x plusmn 1 SD R = 435 plusmn 217) an irregular distributionwas recorded (Fig 5)

DISCUSSION

Abiotic Features-Bottom sea water temperature and salinity variations recordedduring this study are in accordance with the local hydrological patterns (Moreirada Silva 1965 Mascarenhas et aI 1971 Ikeda et aI 1971 Valentin 1984Valentin et aI 1987) The high frequency of cold waters in conjunction with lowsalinity (SACW) in spring and summer (October to March mainly) and warmtropical water and higher salinity (BC and CW) in autumn and winter are due toprevailing E-NE and S-SW winds respectively Costa and Fernandes (1993)showed the relationship between the direction and intensity of wind variationsand upwelling periods from November 1986 to December 1987 and from May1988 to October 1988 on the same study area Upwelling occurred when pre-

Table 4 Number (mean plusmn SO) and biomass of individuals of Astropecten brasiliensis per 100 m2

1986 1987 1988

Depth Wet eight Wet weight Wet weight(m) No (g) No (g) No (g)

30 026 plusmn 032 472 plusmn 508 046 plusmn 117 616 plusmn 1502 071 plusmn 079 1174 plusmn 151945 019 plusmn 023 321 plusmn 399 046 plusmn 074 947 plusmn 1556 129 plusmn 094 1793 plusmn 158560 006 plusmn 009 021 plusmn 047 om plusmn 002 013 plusmn 031 004 plusmn 008 026 plusmn 051

+-obullltDDEJZ

120

80

40

o

120

80

40

o

600

430

360

240

120

o


A

JF~AMJJA~~NDJFMAMJJASONDJFMAMJJASONDI 1986+ I 1987 I 1988 I

B

JFMAMJJA~QNDJFMAMJJASONDJFMAMJJASONDI 1986+ I 987 I 1988 I

c

275

JFMAMJJ~~QNDJFMAMJJASONDJFMAMJJASONDI 1986 I +1987 I + 1988 I

_ A braSiliensis _ L ludwigi scotti D A cingula Ius

Figure 3 Monthly variations in abundance (number of individuals per trawl) of seastars sampled A= 30 m B = 45 m C = 60 m (+) month that no trawl was taken


Table 5 Number (mean plusmn SD) and biomass of Astropecten cingulatus per 100m2

Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wei weight(g)

304560

005 plusmn 006 071 plusmn 069024 plusmn 026 265 plusmn 344071 plusmn 142 483 plusmn 1336



vailing E-NE winds attained 95 mmiddotsec-I and was interrupted when S-SW windsbecame stronger increasing from 25 mmiddotsec-I in November-February 1987 to 75mmiddotsec-I in June-July 1987 Sporadic upwelled waters may also occur due tochanges in wind direction and intensity as recorded in March and August 1987and August 1988 Such changes were caused by predominantly E-NE winds(Costa and Fernandes 1993) Changes in surface sea water temperature and sa-linity can occur after as little as 48 hours during E-NE winds averaging 80msec~1 (Ikeda 1976)

As suggested by Rowe (1985) the benthic subsystem in upwelling ecosystemsmay be divided to ltwOcategories 1) those overloaded with organic matter an-aerobic and dominated by sulfate reduction (for example Peru and SW Africa)and 2) those that are not overloaded with organic matter and remain aerobic (forexample NW Africa and Baja California) The benthos of the area studied shouldbe classified primarily as an aerobic system Dissolved oxygen in bottom waterfluctuated around 50 mlmiddotliter-1 (x plusmn 1 SD = 4766 plusmn 0494 mlmiddotliter-I) and thepercentages of organic carbon of sediment were lower than 055

Abundance and Bathymetric Distribution-Primary productivity of surface wa-ters and depth are major factors determining benthic biomass especially whenoxygen contents of sediment are not limited (Rowe 1971 and 1985) Even thoughlocal water column chlorophyll levels appear very low (reaching 6 -1gmiddot1iter-1

Valentin and Coutinho 1990) when compared to other upwelling regions (25-1gmiddot1iterl at NW Africa Herbland et aI 1973) Cabo Frio upwelling is charac-terized by high levels of detritus (Barth 1973) and zooplanktonic biomass (annualaverage of organic matter of 66 mgmiddotm-3 reaching 280 mgmiddotm-3 Valentin andMoreira 1978) The greatest abundance of seastars was recorded during periodsof upwelling (Fig 4) when densities of the crab Portunus spinicarpus (Brisson1992) and cephalopods (Costa and Fernandes 1993) were also highest Thereforevariations in densities of seastars and other major macrobenthic organisms maybe related to upwelling cycles rather than seasons However the impact of up-welling on benthic biomass and secondary production is not known Significanttemperature fluctuations can yield changes in the sexual maturity cycles and du-ration of planktonic stages of macrofauna (Glemarec and Menesguen 1980) Such

Table 6 Number (mean plusmn SD) and biomass of individuals of Luidia ludwigi scotti per 100 m2

Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wet weight(g)

304560

001 plusmn 002 0004 plusmn 0010005 plusmn 001 -006 plusmn 012 008 plusmn 021



Arm-broken individual


35 355 36 Salinity (0)I

12 SACW

cI14

166~~ 18J(1)

-Q)QE 20~ BC

22 0 bull Obull O~ bull24 0

A braSiliensiso gt 100 Ind

o 10 a lOa Ind

o 1 a 10 indo

A cingulatus

bull gt 100 Ind

bull 10 a 100 Ind

1 a 10 indo

L ludwigi scotti

bull gt100ind

bull 10 a 100 Ind

bull 1 a 10 ind

SACW = South Atlantic Central WaterCW= Coastal WaterBC= Brazil Current

Figure 4 Abundance of seastar species according to the water masses present in the study area Eachpoint represents the number of individuals collected in one trawl

irregularities can destabilize the community from one year to the next both qual-itatively and quantitatively (Glemarec and Menesguen 1980)

The seastars sampled are tropical and widely distributed in the Atlantic Oceanextending even to temperate zones which are influenced by warm waters (Tom-masi 1970 Carrera-Rodriguez and Tommasi 1977 Clark 1982) Their bathy-metric distribution is wide ranging from shallow water to 200-300 m depthsalthough the highest densities occur at shallow depths to 100 m (Carrera-Rodri-guez and Tommasi 1977 Clark 1982) In the study area a distinct bathymetric


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Table 7 Intraspecific comparisons of size-distributions of seastars (Mann-Whitney test) (significancelevel = 005 significant difference)

A brasiliensis A cingulatus L ludwig scali

Calculated Associated Calculated Associated Calculated AssociatedDepths (m) values probabilities values probabilities values probabilities

198630 X 45 06143 0539045 X 60 -21170 00343

198730 X 45 88643 lt0000345 X 60 -56930 lt00001 -47188 lt00001

198830 X 45 -29112 lt0000445 X 60 -50568 lt00001 44379 lt00001

distribution of seastars is evident This pattern seems to be related to character-istics of sediments which vary according to depth Hence A brasiliensis wasmore frequently collected and numerically abundant where sediments were coarser(medium sand at 30 m) A cingulatus and L ludwigi scotti were more frequentin the finer sediment with higher amounts of organic matter (fine sand at 60 m)At 45 m where sediments were mixed three species co-occurred in similar fre-quencies Thus substrate conditions changed gradually and significantly over anarrow bathymetric interval Gomes (1989) also considered the 45 m isobath atransitional zone where species of pelecypods characteristic of 30 and 60 m depthswere found in the same study area The distinct depth distribution of seastars maybe directly related to spatial variations in density of their prey (Ventura 1991)since astropectinids and luidiids are recognized as infaunal predators feedingespecially on mollusks (Jangoux 1982 Nojima 1988) Similar patterns of bathy-metric distribution of A brasiliensis and A cingulatus have been described alongthe southern Brazilian coast (Carrera-Rodriguez and Tommasi 1977)Population Size Structures-Analysis of size-frequency structures of seastar pop-ulations revealed variations among 3 years mainly in 1988 Certainly the appar-ent lack of recruitment in ]986 and] 987 is not an artifact of cod-end mesh sincesmall individuals (1-3 cm R chiefly A brasiliensis and L ludwigi scotti) werecollected in the highest frequency in 1988 using the same sampling technic Therarity of small individuals is often observed in long-term monitoring of echino-derm populations The successful recruitment may vary over long periods Loos-anoff (1964) reported only two mass recruitments of the seastar Asterias forbesiover 25-year period Zann et al (1987) observed only a single large recruitmentof juvenile seastar Acanthaster planci in 9 years of monitoring Also Ebert (1983)recorded only one significant settlement in 16 years of monitoring of the seaurchin Strongylocentrotus purpuratus population Unpredictable and rare suc-cessful recruitments are not surprising in these species since they have a long-lived (of several weeks) pelagic larval phase (Johnson 1992) The larvae aresubject to hydrological processes which may provide long dispersal distancesTherefore the recruitment rate is independent of local densities As a result thelocal populations are generally open (since all recruits may come from otherregions) and recruitment-limited (Roughgarden and Iwasa 1986 Karlson andLevitan 1990) Considering hydrological dynamics of the studied area it is pos-sible that local larvae could be transported to the offshore Pedrotti and Fenaux

280 BULLETIN OF MARINE SCIENCE VOL 56 NO1 1995

(1992) reported a maximal dispersal distance of echinoderm larvae of 28 milesin an upwelling area of Mediterranean However coastal upwelling may act asefficient or inefficient factor on larval dispersal according to its intensity andfrequency (Ebert and Russell 1988 Pedrotti and Fenaux 1992) Up to now thereis not enough information on seastar reproduction or larval dispersal from thestudied area to be relatedto upwelling events

Size-frequency distributions of A brasiliensis showed that the largest individ-uals (6-10 cm R) were most common at the depth of 45 m where they coexistedwith smaller (1-6 cm R) A cingulatus The smallest individuals (1-5 cm R)were abundant at 30 m where A brasiliensis was dominant Size-frequency dis-tributions of A cingulatus were similar at 45 and 60 m depths Similar situationwas described by Ribi et ai (1977) for other Astropecten species in Mediterra-nean Differences between diets of each species led the authors to suggest thatcharacter displacement was occurring Further information on the feeding pref-erences of Astropecten species and prey abundance (Ventura et aI in prep) arenecessary to understand the distribution pattern of these seastars in Cabo Frioregion

ACKNOWLEDGMENTS

We are thankful to J M Lawrence J B McClintock for reviewing earlier versions of the manuscriptand for making helpful suggestions both with regard to content and editorial style R R Iglesiasprovided valuable insights into the population ecology of seastars D L Pawson kindly assisted withsystematics information This research was supported by Brazilian Navy and National Research Coun-cil of Brazil (CNPq)

LITERATURE CITED

Alverson D L ed 1971 Manual of methods for fisheries research Survey and appraisal Part IISurvey and charting of fishering resources Fao Fish Tech Paper Vol 102 80 pp

Barth R 1973 Contribui~6es ao conhecimento do seston na costa do Brasil Publ Inst Pesq Mar77 1-33

Bernasconi I 1957 Otra nueva especie de asteroideo brasileno Neotropica 3 33-34Blake D B 1990 Adaptive zones of the class asteroidea (Echinodermata) Bull Mar Sci 46 701-

718Brisson S 1992 Estudos sobre a popula~ao de Portunus spinicarpus (Stimpson 1871) (Crustacea

Decapoda Brachyura) da regiao de Cabo Frio Brasil MSc Dissertation Universidade Federaldo Rio de JaneirolMuseu Nacional 118 pp

Brito I M 1968 Aster6ides e equin6ides do Estado da Guanabara e adjacencias Bolm Mus NacRio de J 260 1-51

Buchanan J B 1984 Sediment analysis Pages 41-65 in N A Holme and A D McIntyre eds IBPhand book 16 methods for study of marine benthos 2nd ed Blackwell Scientific PublicationLondon

Carrera-Rodriguez C J and L R Tommasi 1977 Asteroidea de la plataforma continental de RioGrande do Sui (Brasil) coleccionados durante los viajes del NOc Prof Besnard para elprojecto Rio Grande do SuI Bolm Inst Oceanogr S Paulo 26 51-130

Clark A M 1982 Notes on Atlantic Asteroidea 2 Ludiidae Bull Br Mus Nat Hist (Zool) 42(3)157-184

--- and M E Downey 1992 Starfishes of the Atlantic Chapman amp Hall London 794 ppCosta P A S and F C Fernandes 1993 Seasonal and spatial changes of cephalopods caught in the

Cabo Frio (Brazil) upwelling ecosystem Bull Mar Sci 52 751-759Ebert T A 1983 Recruitment in echinoderms Pages 169-203 in M Jangoux and J M Lawrence

eds Echinoderm studies Vol 1 A A Balkema Publ Rotterdam--- and M P Russell 1988 Latitudinal variation in size structure of west coast purple urchin a

correlation with headlands Limnol Oceanogr 33 286-294Glemarec M and A Menesguen 1980 Functioning of muddy sand ecosystem seasonal fluctuations

of different trophic levels and difficulties in estimating production of the dominant macrofaunaspecies Pages 49-68 in K R Tenore and B Coull eds The Belle W Baruch Library in Marine

VENTURA AND FERNANDES BRAZILIAN PAXlLLOSID SEASTARS 281

Science 11 marine benthic dynamics University of South Carolina Press Columbia South Car-olina

Gomes A S 1989 Distribui~iio espacial dos moluscos bivalves na Praia de Ma bullbullambaba Arraial doCabo RJ MSc Dissertation Museu Nacional Universidade Federal do Rio de Janeiro 121 pp

Herbland A R Le Borgne and B Voituriez 1973 Production primaire secondaire et regenerationdes sels nutritifs dans Iupwelling de Mauritanie Doc Sci Cent Rech Oceanogr Abidjan 475 pp

Ikeda Y 1976 Variations in mean scale of temperature and salinity in the sea region betweenGuanabara Bay and Cabo Frio (August 17-26 1971) Bolm Inst Oceanogr S Paulo 25 221-280

--- L B Miranda and N J Rock 1971 Observations on stages of upwelling in the region ofCabo Frio (Brazil) as conducted by continuous surface temperature and salinity measurementsPages 74--97 in Proceedings of the United Nations Panels Meeting on the Establishment andImplementation of Research Programmes in Remote Sensing Report 14 United Nations NewYork

Ingram R L 1971 Sieve Analysis Pages 49--67 in R E Carver ed Procedures in sedimentarypetrology Wiley Interscience New York

Jangoux M 1982 Food and feeding mechanisms Asteroidea Pages 117-159 in M Jangoux and JM Lawrence eds Echinoderm nutrition A A Balkema Publ Rotterdam

Johnson C 1992 Settlement and recruitment of Acanthaster planci on the Great Barrier Reef ques-tions of process and scale Aust J Mar Freshwater Res 43 611--627

Karlson R H and D R Levitan 1990 Recruitment-limitation in open populations of Diadernaantillarurn an evaluation Oecologia 82 40-44

Loosanoff V L 1964 Variation in time and intensity of setting of the starfish Asterias forbesi inLong Island Sound during a twenty-five year period BioI Bull 126 423-439

Manso C L C 1989 Os Echinodermata da plataforma continental interna entre Cabo Frio e Sa-quarema Rio de Janeiro Brasil Rev Brasil BioI 49 355-359

Mascarenhas A S L B Miranda and N J Rock 1971 A study of the oceanographic conditionsin the region of Cabo Frio Pages 285-308 in J D J Costlow ed Fertility of the sea Vol 1Gordon and Breach New York

Moreira da Silva P C 1965 Problemas da circula~iio oceanica nas aguas brasileiras An AcadBrasil Cienc 37 157-165

Mukai H M Nishihira H Kamisato and Y Fujimoto 1986 Distribution and abundance of the sea-star Archaster typicus in Kabira Cove Ishigaki Island Okinawa Bull Mar Sci 38 366-383

Nojima S 1988 Stomach contents and feeding habits of four sympatric sea stars genus Astropecten(Echinodermata Asteroidea) from northern Kyushu Japan Publ Amakusa Mar BioI Lab 967-76

Pauly D 1984 Fish population dynamics in tropical waters a manual for use with programmablecalculators ICLARM Stud Rev 8 1-325

Pedrotti M L and L Fenaux 1992 Dispersal of echinoderm larvae in a geographical area markedby upwelling (Ligurian Sea NW Mediterranean) Mar Ecol Prog Ser 86 217-227

Ribi G R Scharer and P Oschner 1977 Stomach contents and size-frequency distribution of twocoexisting sea star species Astropecten aranciacus and A bispinosus with reference to compe-tition Mar BioI 43 181-185

Rodriguez E G J L Valentin D L Andre and S A Jacob 1992 Upwelling and downwelling atCabo Frio (Brazil) comparison of biomass and primary production responses J Plankton Res14 289-306

Roughgarden J and Y Iwasa 1986 Dynamics of a metapopulation with space-limited subpopula-tions Theor Pop BioI 29 235-261

Rowe G T 1971 Benthic biomass and surface productivity Pages 441-454 in J D Costlow edFertility of the sea Vol 1 Gordon and Breach New York

--- 1985 Benthic production and process off Baja California Northwest Africa and Peru aclassification of benthic subsystems in upwelling ecosystems Pages 589--612 in Inst Inv PesqInt Symp Upw W Afr Vol II Inst Inv Pesq Barcelona

Siegel S 1975 Estatfstica niio-parametrica McGraw-Hill Sao Paulo 350 ppSokal R R and F J Rohlf 1981 Biometry 2nd ed W H Freeman and Company New York 859 ppStrickland J D H and T R Parsons 1972 A practical handbook of seawater analysis Bull Fish

Res Bd Can 167 310 ppThomsen H 1962 Massas de agua caracteristicas del Atlantico (parte sudoeste) Servo Hidrografia

Naval Secret Mar H (Buenos Aires Public) 632 1-27Thrush S F 1991 Spatial patterns in soft-bottom communities TREE 6 75-79Tommasi L R 1958 Os equinodermas do litoral de Siio Paulo II-Diadematidae Schiasteridae

282 BULLETINOFMARINESCIENCEVOL56 NOI 1995

Brissidae Cidaroidea (Echinoidea) e Asteroidea do bentos costeiro Contri~()es Inst OceanogrUniv S Paulo 2 1--39

--- 1961 Equinodermas do Estado do Rio de Janeiro I-Crinoidea Asteroidea Echinoidea eHoloturoidea da regiao compreendida entre 0 Cabo de Buzios e Cabo Frio An Acad BrasilCienc 31 601-604

--- 1970 Lista dos aster6ides recentes do Brasil Contri~6es Inst oceanogr Univ S Paulo SerOcean BioI 18 1-61

--- 1974 Equinod~rmes do Brasil III-Observa~6es sobre algumas especies coletadas duranteas viagens do NOc Almirante Saldanha Bolm Inst Oceanogr S Paulo 23 1-15

--- 1985 Equinod~rmas da regiao da I1ha da Vit6ria (SP) Relat Int Inst Oceanogr Univ SPaulo 13 1-5

Valentin J L 1984 Analyse des parametres hydrobiologiques dans la remontee de Cabo Frio (Bresil)Mar BioI 82 259-276

--- and R Coutinho 1990 Modelling maximum chlorophyll in the Cabo Frio (Brazil) upwellinga preliminary approach Ecol Modelling 52 103-113

--- and PMoreira 1978 A materia organica de origem zooplanct6nica nas aguas da ressurgenciado Cabo Frio (Brasil) An Acad Brasil Cienc 50 103-112

--- D L Andre and S A Jacob 1987 Hydrobiology in the Cabo Frio (Brazil) upwelling two-dimensional structun~and variability during a wind cycle Cont Shelf Res 7 77-88

Van Valen L 1971 Adaptive zones and the orders of mammals Evolution 25 420-428Ventura C R R 1991 Distribui~ao abundancia e habito alimentar de Asteroidea (Echinodermata)

de fundos inconsolidados da plataforma continental do Cabo Frio RJ MSc Dissertation MuseuNacionallUniversidade Federal do Rio de Janeiro 101 pp

Zann L J Brodie C Berryman and M Naqasima 1987 Recruitment ecology growth and behav-iour of juvenile Acanthaster planci (L) (Echinodermata Asteroidea) Bull Mar Sci 41 461-475

Zar J H 1984 Biostatistical analysis Prentice Hall New York 717 pp

DATEACCEPTEDMay 13 1993

ADDRESSES(CRRV) Departamento de Biologia Marinha Instituto de Biologia UniversidadeFederal do Rio de Janeiro Rio de Janeiro RJ Brazil 21949-900 (FCF) Instituto de Estudos doMar Almirante Paulo Moreira Arraial do Cabo RJ Brazil 28930-000


The purpose of this study was to describe the bathymetric distribution abundanceand population size structure of seastars from an upwelling region of the CaboFrio continental shelf These aspects are interpreted in the light of sea watersalinity and temperature data as well as information on sediment grain size andorganic content

STUDY AREAThe Cabo Frio region (23degS 42degW) is in the central-southern littoral zone of Brazil The shore line

bends inwards abruptly from N-S to E-W and the continental shelf becomes narrow Consequently100 and 200 m depths occur near the coast (Valentin 1984) (Fig I) During spring-summer (Septem-ber to March) the prevailing E-NE winds and Coriolis effects cause upwelling of subtropical waters(South Atlantic Central Water SACW) resulting in temperatures lower than 18degC salinities lowerthan 360 and nitrate concentration higher than 10 mmolmiddotm-3 (Thomsen 1962 Valentin et aI 1987Rodriguez et aI 1992) Downwelling occurs when S-SW winds cause the replacement of SACWwith tropical warmer water (Brazil Current BC and Coastal Water CW) The upwelling cycle isinterrupted most frequently during winter (June to August) (Valentin 1984 Valentin et aI 1987Rodriguez et aI 1992)

MATERIALS AND METHODS

Seastars were sampled by conducting one 20-min trawl monthly along Maambaba Beach Arraialdo Cabo RJ (22deg57S 23deg00S 47deg07W 42deg11 W) at depths of 3045 and 60 m from January 1986to December 1988 The otter-trawl was equipped with a 12-m footrope and cod-end mesh with a sizeof 25 mm All trawls were conducted in daylight (10 AM to 3 PM) at a speed of approximately 30kn The area sampled in each trawl was approximately 2620 m2 as estimated by methods of Alverson(1971) and Pauly (1984) Bottom sea water was sampled with a Nansen bottle at six oceanographicstations (Fig I) Water temperature was measured at each station using a reversing thermometerSalinity was measured with a Beckman induction salinometer and dissolved oxygen by the Winklermethod (Strickland and Parsons 1972)

Sediment samples were collected using a Van- Veen grab (01 m2) at each depth from April 1986to February 1987 Granulometrical sediment fractions were determined according to Ingram (1971)The size-distribution of grains was expressed in dry weight and statistical grain parameters werecalculated according to Buchanan (1984) A portion of the sediment samples (100 g) was used formeasuring the proportion of calcium carbonate and organic carbon The former was expressed aspercent weight loss after HCI treatment and the latter by chromic acid organic matter oxidation bothon a dry weight basis (Buchanan 1984)

Abundance of seas tars was determined considering the number of individuals sampled per trawlSize-distributions of seastars were estimated by measuring the radius (R) (the distance from the

mouth to the longest arm tip 1 mm accuracy) Bathymetric differences in the size-distributions ofseastars and in the bottom sea water and sediment parameters were statistically analyzed using a Chi-square test and Mann-Whitney and Kruskal-WaIlis rank tests respectively (Siegel 1975 Sokal andRohlf 1981) The Thkeys test for non-parametric randomized block analysis of variance was calcu-lated following Kruskal-Wallis Analysis (Zar 1984)

After measurement seastars were fixed in 5 formaldehyde and preserved in 70 alcohol Allspecies collected were identified according to Tommasi (1970) Clark (1982) and Clark and Downey(1992) Specimens were deposited in the Echinodermata collection of the Museu Nacional (Univer-sidade Federal do Rio de Janeiro)

RESULTS

Abiotic Features of Bottom Water and Sediment-Bottom sea water temperatureranged from 128degC (November 1988 at 45 m) to 242degC (May 1988 at 30 m)Of all samples 64 were collected in cold water (lower than 18degC) mostlyoccurring in summer (33) and spring (29) Low sea water temperatures wereless frequent in autumn (22) and winter (16) Warmer sea water bottom tem-peratures were recorded more frequently in winter (50) and autumn (34) thanin spring (9) and summer (6) Monthly variations in bottom sea water tem-perature reflect this tendency for colder water to be present during summer andspring (Fig 2) Mean bottom sea water temperatures decreased with increasing


---- -----~--


- --100 bullbull

N

1-

LAGOON

~lll


-- So 11011I 11

ATLANTIC OCEAN





30


271

o 26o

~ 22JCOCD 18QE~ 14



0-(flt 36

35 35


7


Months

bullbull(J)


o

6

4
















0-OO~~ ~OCi~~~ ~q-N


~~O~C0~0-00-NltI

lt1lt


~-- r-


bull


Eo

Eo

00~ Eu




DepthSpecies


30 1986 72 (3181) 13 (5157) 2 (361)45 48 (3876) 57 (6284) 1 (440) P lt 00160 12 (6143) 144 (9959) 12 (558)

30 1987 143 (4564) 11 (7732) 3 (3403)45 146 (10000) 110 (16942) 88 (7457) P lt 00160 2 (14535) 372 (24625) 126 (10839)

30 1988 248 (6271) 1 (14551) 11 (5177)45 406 (172 70) 113 (40072) 197 (14258) P lt om60 11 (42958) 1429 (99677) 341 (35465)


DISCUSSION



1986 1987 1988



+-obullltDDEJZ

120

80

40

o

120

80

40

o

600

430

360

240

120

o


A


B


c

275






Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wei weight(g)

304560









Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wet weight(g)

304560






35 355 36 Salinity (0)I

12 SACW

cI14

166~~ 18J(1)

-Q)QE 20~ BC



o 10 a lOa Ind

o 1 a 10 indo

A cingulatus

bull gt 100 Ind

bull 10 a 100 Ind

1 a 10 indo

L ludwigi scotti

bull gt100ind

bull 10 a 100 Ind

bull 1 a 10 ind






00til

A 0 N 3 n 0 3 ~ ~()o is

2

0 ltlt lJ


ltD sectgt to (J)

~to ~ sect(]) -~

jj

j

~-

Cillgt

(j) ~- ltl)

Q) gt~ 0

Q) cE tl

cfil 53 g 2 0 5l ~ 53 pound 2 0 g ~ g 2 2 0 0

CO 0

~$I 0 gt

l c



~ - 0lJ 2 ~ (j) JS-Q) tl

()~ ltl)

Q) E bull

[JJZlgt gt 0

LO c0

ltj- S~

IE

Ic

c( 5

[ a ugt()

(j) cltl)

-

2 0

2 ~ 53 2 2 0 g til 2 2 0 5l ~ til 0 2 ~ Q)

E ltl)lt1 7l 2 N

~ ~ iii 0 Vi ~ ()co

lIiltD

I-


bI)ti





198630 X 45 06143 0539045 X 60 -21170 00343

198730 X 45 88643 lt0000345 X 60 -56930 lt00001 -47188 lt00001

198830 X 45 -29112 lt0000445 X 60 -50568 lt00001 44379 lt00001





ACKNOWLEDGMENTS


LITERATURE CITED


























































---- -----~--


- --100 bullbull

N

1-

LAGOON

~lll


-- So 11011I 11

ATLANTIC OCEAN





30


271

o 26o

~ 22JCOCD 18QE~ 14



0-(flt 36

35 35


7


Months

bullbull(J)


o

6

4
















0-OO~~ ~OCi~~~ ~q-N


~~O~C0~0-00-NltI

lt1lt


~-- r-


bull


Eo

Eo

00~ Eu




DepthSpecies


30 1986 72 (3181) 13 (5157) 2 (361)45 48 (3876) 57 (6284) 1 (440) P lt 00160 12 (6143) 144 (9959) 12 (558)

30 1987 143 (4564) 11 (7732) 3 (3403)45 146 (10000) 110 (16942) 88 (7457) P lt 00160 2 (14535) 372 (24625) 126 (10839)

30 1988 248 (6271) 1 (14551) 11 (5177)45 406 (172 70) 113 (40072) 197 (14258) P lt om60 11 (42958) 1429 (99677) 341 (35465)


DISCUSSION



1986 1987 1988



+-obullltDDEJZ

120

80

40

o

120

80

40

o

600

430

360

240

120

o


A


B


c

275






Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wei weight(g)

304560









Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wet weight(g)

304560






35 355 36 Salinity (0)I

12 SACW

cI14

166~~ 18J(1)

-Q)QE 20~ BC



o 10 a lOa Ind

o 1 a 10 indo

A cingulatus

bull gt 100 Ind

bull 10 a 100 Ind

1 a 10 indo

L ludwigi scotti

bull gt100ind

bull 10 a 100 Ind

bull 1 a 10 ind






00til

A 0 N 3 n 0 3 ~ ~()o is

2

0 ltlt lJ


ltD sectgt to (J)

~to ~ sect(]) -~

jj

j

~-

Cillgt

(j) ~- ltl)

Q) gt~ 0

Q) cE tl

cfil 53 g 2 0 5l ~ 53 pound 2 0 g ~ g 2 2 0 0

CO 0

~$I 0 gt

l c



~ - 0lJ 2 ~ (j) JS-Q) tl

()~ ltl)

Q) E bull

[JJZlgt gt 0

LO c0

ltj- S~

IE

Ic

c( 5

[ a ugt()

(j) cltl)

-

2 0

2 ~ 53 2 2 0 g til 2 2 0 5l ~ til 0 2 ~ Q)

E ltl)lt1 7l 2 N

~ ~ iii 0 Vi ~ ()co

lIiltD

I-


bI)ti





198630 X 45 06143 0539045 X 60 -21170 00343

198730 X 45 88643 lt0000345 X 60 -56930 lt00001 -47188 lt00001

198830 X 45 -29112 lt0000445 X 60 -50568 lt00001 44379 lt00001





ACKNOWLEDGMENTS


LITERATURE CITED


























































30


271

o 26o

~ 22JCOCD 18QE~ 14



0-(flt 36

35 35


7


Months

bullbull(J)


o

6

4
















0-OO~~ ~OCi~~~ ~q-N


~~O~C0~0-00-NltI

lt1lt


~-- r-


bull


Eo

Eo

00~ Eu




DepthSpecies


30 1986 72 (3181) 13 (5157) 2 (361)45 48 (3876) 57 (6284) 1 (440) P lt 00160 12 (6143) 144 (9959) 12 (558)

30 1987 143 (4564) 11 (7732) 3 (3403)45 146 (10000) 110 (16942) 88 (7457) P lt 00160 2 (14535) 372 (24625) 126 (10839)

30 1988 248 (6271) 1 (14551) 11 (5177)45 406 (172 70) 113 (40072) 197 (14258) P lt om60 11 (42958) 1429 (99677) 341 (35465)


DISCUSSION



1986 1987 1988



+-obullltDDEJZ

120

80

40

o

120

80

40

o

600

430

360

240

120

o


A


B


c

275






Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wei weight(g)

304560









Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wet weight(g)

304560






35 355 36 Salinity (0)I

12 SACW

cI14

166~~ 18J(1)

-Q)QE 20~ BC



o 10 a lOa Ind

o 1 a 10 indo

A cingulatus

bull gt 100 Ind

bull 10 a 100 Ind

1 a 10 indo

L ludwigi scotti

bull gt100ind

bull 10 a 100 Ind

bull 1 a 10 ind






00til

A 0 N 3 n 0 3 ~ ~()o is

2

0 ltlt lJ


ltD sectgt to (J)

~to ~ sect(]) -~

jj

j

~-

Cillgt

(j) ~- ltl)

Q) gt~ 0

Q) cE tl

cfil 53 g 2 0 5l ~ 53 pound 2 0 g ~ g 2 2 0 0

CO 0

~$I 0 gt

l c



~ - 0lJ 2 ~ (j) JS-Q) tl

()~ ltl)

Q) E bull

[JJZlgt gt 0

LO c0

ltj- S~

IE

Ic

c( 5

[ a ugt()

(j) cltl)

-

2 0

2 ~ 53 2 2 0 g til 2 2 0 5l ~ til 0 2 ~ Q)

E ltl)lt1 7l 2 N

~ ~ iii 0 Vi ~ ()co

lIiltD

I-


bI)ti





198630 X 45 06143 0539045 X 60 -21170 00343

198730 X 45 88643 lt0000345 X 60 -56930 lt00001 -47188 lt00001

198830 X 45 -29112 lt0000445 X 60 -50568 lt00001 44379 lt00001





ACKNOWLEDGMENTS


LITERATURE CITED






































































0-OO~~ ~OCi~~~ ~q-N


~~O~C0~0-00-NltI

lt1lt


~-- r-


bull


Eo

Eo

00~ Eu




DepthSpecies


30 1986 72 (3181) 13 (5157) 2 (361)45 48 (3876) 57 (6284) 1 (440) P lt 00160 12 (6143) 144 (9959) 12 (558)

30 1987 143 (4564) 11 (7732) 3 (3403)45 146 (10000) 110 (16942) 88 (7457) P lt 00160 2 (14535) 372 (24625) 126 (10839)

30 1988 248 (6271) 1 (14551) 11 (5177)45 406 (172 70) 113 (40072) 197 (14258) P lt om60 11 (42958) 1429 (99677) 341 (35465)


DISCUSSION



1986 1987 1988



+-obullltDDEJZ

120

80

40

o

120

80

40

o

600

430

360

240

120

o


A


B


c

275






Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wei weight(g)

304560









Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wet weight(g)

304560






35 355 36 Salinity (0)I

12 SACW

cI14

166~~ 18J(1)

-Q)QE 20~ BC



o 10 a lOa Ind

o 1 a 10 indo

A cingulatus

bull gt 100 Ind

bull 10 a 100 Ind

1 a 10 indo

L ludwigi scotti

bull gt100ind

bull 10 a 100 Ind

bull 1 a 10 ind






00til

A 0 N 3 n 0 3 ~ ~()o is

2

0 ltlt lJ


ltD sectgt to (J)

~to ~ sect(]) -~

jj

j

~-

Cillgt

(j) ~- ltl)

Q) gt~ 0

Q) cE tl

cfil 53 g 2 0 5l ~ 53 pound 2 0 g ~ g 2 2 0 0

CO 0

~$I 0 gt

l c



~ - 0lJ 2 ~ (j) JS-Q) tl

()~ ltl)

Q) E bull

[JJZlgt gt 0

LO c0

ltj- S~

IE

Ic

c( 5

[ a ugt()

(j) cltl)

-

2 0

2 ~ 53 2 2 0 g til 2 2 0 5l ~ til 0 2 ~ Q)

E ltl)lt1 7l 2 N

~ ~ iii 0 Vi ~ ()co

lIiltD

I-


bI)ti





198630 X 45 06143 0539045 X 60 -21170 00343

198730 X 45 88643 lt0000345 X 60 -56930 lt00001 -47188 lt00001

198830 X 45 -29112 lt0000445 X 60 -50568 lt00001 44379 lt00001





ACKNOWLEDGMENTS


LITERATURE CITED



























































DepthSpecies


30 1986 72 (3181) 13 (5157) 2 (361)45 48 (3876) 57 (6284) 1 (440) P lt 00160 12 (6143) 144 (9959) 12 (558)

30 1987 143 (4564) 11 (7732) 3 (3403)45 146 (10000) 110 (16942) 88 (7457) P lt 00160 2 (14535) 372 (24625) 126 (10839)

30 1988 248 (6271) 1 (14551) 11 (5177)45 406 (172 70) 113 (40072) 197 (14258) P lt om60 11 (42958) 1429 (99677) 341 (35465)


DISCUSSION



1986 1987 1988



+-obullltDDEJZ

120

80

40

o

120

80

40

o

600

430

360

240

120

o


A


B


c

275






Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wei weight(g)

304560









Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wet weight(g)

304560






35 355 36 Salinity (0)I

12 SACW

cI14

166~~ 18J(1)

-Q)QE 20~ BC



o 10 a lOa Ind

o 1 a 10 indo

A cingulatus

bull gt 100 Ind

bull 10 a 100 Ind

1 a 10 indo

L ludwigi scotti

bull gt100ind

bull 10 a 100 Ind

bull 1 a 10 ind






00til

A 0 N 3 n 0 3 ~ ~()o is

2

0 ltlt lJ


ltD sectgt to (J)

~to ~ sect(]) -~

jj

j

~-

Cillgt

(j) ~- ltl)

Q) gt~ 0

Q) cE tl

cfil 53 g 2 0 5l ~ 53 pound 2 0 g ~ g 2 2 0 0

CO 0

~$I 0 gt

l c



~ - 0lJ 2 ~ (j) JS-Q) tl

()~ ltl)

Q) E bull

[JJZlgt gt 0

LO c0

ltj- S~

IE

Ic

c( 5

[ a ugt()

(j) cltl)

-

2 0

2 ~ 53 2 2 0 g til 2 2 0 5l ~ til 0 2 ~ Q)

E ltl)lt1 7l 2 N

~ ~ iii 0 Vi ~ ()co

lIiltD

I-


bI)ti





198630 X 45 06143 0539045 X 60 -21170 00343

198730 X 45 88643 lt0000345 X 60 -56930 lt00001 -47188 lt00001

198830 X 45 -29112 lt0000445 X 60 -50568 lt00001 44379 lt00001





ACKNOWLEDGMENTS


LITERATURE CITED

























































+-obullltDDEJZ

120

80

40

o

120

80

40

o

600

430

360

240

120

o


A


B


c

275






Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wei weight(g)

304560









Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wet weight(g)

304560






35 355 36 Salinity (0)I

12 SACW

cI14

166~~ 18J(1)

-Q)QE 20~ BC



o 10 a lOa Ind

o 1 a 10 indo

A cingulatus

bull gt 100 Ind

bull 10 a 100 Ind

1 a 10 indo

L ludwigi scotti

bull gt100ind

bull 10 a 100 Ind

bull 1 a 10 ind






00til

A 0 N 3 n 0 3 ~ ~()o is

2

0 ltlt lJ


ltD sectgt to (J)

~to ~ sect(]) -~

jj

j

~-

Cillgt

(j) ~- ltl)

Q) gt~ 0

Q) cE tl

cfil 53 g 2 0 5l ~ 53 pound 2 0 g ~ g 2 2 0 0

CO 0

~$I 0 gt

l c



~ - 0lJ 2 ~ (j) JS-Q) tl

()~ ltl)

Q) E bull

[JJZlgt gt 0

LO c0

ltj- S~

IE

Ic

c( 5

[ a ugt()

(j) cltl)

-

2 0

2 ~ 53 2 2 0 g til 2 2 0 5l ~ til 0 2 ~ Q)

E ltl)lt1 7l 2 N

~ ~ iii 0 Vi ~ ()co

lIiltD

I-


bI)ti





198630 X 45 06143 0539045 X 60 -21170 00343

198730 X 45 88643 lt0000345 X 60 -56930 lt00001 -47188 lt00001

198830 X 45 -29112 lt0000445 X 60 -50568 lt00001 44379 lt00001





ACKNOWLEDGMENTS


LITERATURE CITED



























































Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wei weight(g)

304560









Depth(m) No

1986

Wet weight(g) No

1987

Wet weight(g) No

1988

Wet weight(g)

304560






35 355 36 Salinity (0)I

12 SACW

cI14

166~~ 18J(1)

-Q)QE 20~ BC



o 10 a lOa Ind

o 1 a 10 indo

A cingulatus

bull gt 100 Ind

bull 10 a 100 Ind

1 a 10 indo

L ludwigi scotti

bull gt100ind

bull 10 a 100 Ind

bull 1 a 10 ind






00til

A 0 N 3 n 0 3 ~ ~()o is

2

0 ltlt lJ


ltD sectgt to (J)

~to ~ sect(]) -~

jj

j

~-

Cillgt

(j) ~- ltl)

Q) gt~ 0

Q) cE tl

cfil 53 g 2 0 5l ~ 53 pound 2 0 g ~ g 2 2 0 0

CO 0

~$I 0 gt

l c



~ - 0lJ 2 ~ (j) JS-Q) tl

()~ ltl)

Q) E bull

[JJZlgt gt 0

LO c0

ltj- S~

IE

Ic

c( 5

[ a ugt()

(j) cltl)

-

2 0

2 ~ 53 2 2 0 g til 2 2 0 5l ~ til 0 2 ~ Q)

E ltl)lt1 7l 2 N

~ ~ iii 0 Vi ~ ()co

lIiltD

I-


bI)ti





198630 X 45 06143 0539045 X 60 -21170 00343

198730 X 45 88643 lt0000345 X 60 -56930 lt00001 -47188 lt00001

198830 X 45 -29112 lt0000445 X 60 -50568 lt00001 44379 lt00001





ACKNOWLEDGMENTS


LITERATURE CITED


























































35 355 36 Salinity (0)I

12 SACW

cI14

166~~ 18J(1)

-Q)QE 20~ BC



o 10 a lOa Ind

o 1 a 10 indo

A cingulatus

bull gt 100 Ind

bull 10 a 100 Ind

1 a 10 indo

L ludwigi scotti

bull gt100ind

bull 10 a 100 Ind

bull 1 a 10 ind






00til

A 0 N 3 n 0 3 ~ ~()o is

2

0 ltlt lJ


ltD sectgt to (J)

~to ~ sect(]) -~

jj

j

~-

Cillgt

(j) ~- ltl)

Q) gt~ 0

Q) cE tl

cfil 53 g 2 0 5l ~ 53 pound 2 0 g ~ g 2 2 0 0

CO 0

~$I 0 gt

l c



~ - 0lJ 2 ~ (j) JS-Q) tl

()~ ltl)

Q) E bull

[JJZlgt gt 0

LO c0

ltj- S~

IE

Ic

c( 5

[ a ugt()

(j) cltl)

-

2 0

2 ~ 53 2 2 0 g til 2 2 0 5l ~ til 0 2 ~ Q)

E ltl)lt1 7l 2 N

~ ~ iii 0 Vi ~ ()co

lIiltD

I-


bI)ti





198630 X 45 06143 0539045 X 60 -21170 00343

198730 X 45 88643 lt0000345 X 60 -56930 lt00001 -47188 lt00001

198830 X 45 -29112 lt0000445 X 60 -50568 lt00001 44379 lt00001





ACKNOWLEDGMENTS


LITERATURE CITED


























































00til

A 0 N 3 n 0 3 ~ ~()o is

2

0 ltlt lJ


ltD sectgt to (J)

~to ~ sect(]) -~

jj

j

~-

Cillgt

(j) ~- ltl)

Q) gt~ 0

Q) cE tl

cfil 53 g 2 0 5l ~ 53 pound 2 0 g ~ g 2 2 0 0

CO 0

~$I 0 gt

l c



~ - 0lJ 2 ~ (j) JS-Q) tl

()~ ltl)

Q) E bull

[JJZlgt gt 0

LO c0

ltj- S~

IE

Ic

c( 5

[ a ugt()

(j) cltl)

-

2 0

2 ~ 53 2 2 0 g til 2 2 0 5l ~ til 0 2 ~ Q)

E ltl)lt1 7l 2 N

~ ~ iii 0 Vi ~ ()co

lIiltD

I-


bI)ti





198630 X 45 06143 0539045 X 60 -21170 00343

198730 X 45 88643 lt0000345 X 60 -56930 lt00001 -47188 lt00001

198830 X 45 -29112 lt0000445 X 60 -50568 lt00001 44379 lt00001





ACKNOWLEDGMENTS


LITERATURE CITED





























































198630 X 45 06143 0539045 X 60 -21170 00343

198730 X 45 88643 lt0000345 X 60 -56930 lt00001 -47188 lt00001

198830 X 45 -29112 lt0000445 X 60 -50568 lt00001 44379 lt00001





ACKNOWLEDGMENTS


LITERATURE CITED




























































ACKNOWLEDGMENTS


LITERATURE CITED

























































@?RFWKCRPGA BGQRPG@SRGML ?LB NMNSJ?RGML ..._kiikj ]p 23 i ]j` 4. i %bnki sahh pk ik`an]pahu+sahh...

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Transcript of @?RFWKCRPGA BGQRPG@SRGML ?LB NMNSJ?RGML ..._kiikj ]p 23 i ]j` 4. i %bnki sahh pk ik`an]pahu+sahh...