Rev. Biol. Trop., 31(1): 75-101, 1983

Occurrence, distribution , abundan ce and diversity of fIS hes in the Gulf of Nicoya, Costa Rica

Charles E. Bartels and Kent S. Price University of De1aware, College of Marine Studies, Lewes , Delaware 1995 8, U.S.A. Myrna I. López and William A. Bussing Universidad de Costa Rica, San Pedro, Costa Rica

(Received for publication December 13, 1982)

Trawl samples of demersal fish populations within the Gulf of Nicoya, Costa Rica were Abstract:conducted during February and July, 1979 and April, 1980 in an attempt to define basic abundance, diversity and distributional patterns. Seventeen day and three night samples produced 6,441 fishes of 107 species during the February cruise. Twenty day and two night samples produced 9,220 individuals of 131 species during the July cruise. Twenty day samples produced 14,151 individuals representing 125 species taken during the April cruise. A total of 214 species were collected during this study. The Gulf of Nicoya may be divided into three zones on the basis of the physical characteristicsof the stations (water temperature, dissolved oxygen, salinity, depth and distan ce from the mouth of the Gulf). Few changes in the position of these zones occurred during the study period, indicating a relatively stablees­ tuarine configuration from a biological perspective, under the influence of a wet and a dry season. No signifi­ cant seasonal changes in the number, biomass, percent occurrence, diversity of partitioning by size class of fishes were observed. Two major types of fish distributional patterns were observed. Several species we re ubiquitous and were found throughout the Gulf in varying abundances. Other species w-ere restricted to either the upper or lower Gulf. Dominant groups in the upper Gulf include the sciaenids, sea catfishes (Ariidae) and fla tfishes (Soleidae, Cynoglossidae and Syacium ovale). These fishes tend to inhabit the warmer, shallower, less saline waters of the upper Gulf. Flounders (Bothidae), gobies (Bollmannia spp .), morays and congers (Hildeb randia nitens, Priodonophus equatorialis and Muraenesox coniceps) and several other species dominated the deeper, cooler, more saline lower Gulf.

While there have been severa! studies of biomass, number of species and number of various fishes or small groups of fish in the individuals captured. Stevenson (1978) Gulf of Nicoya, these studies have not, for attempted to predict the maximum sus­ the most part, dea!t with the overall distri­ tainable yield of selected fish species in the butiona! pattern of demersal fishes through­ Gulf using the Beverton-Holt yield mode!. out the entire Gulf. Peterson (1956) studied The reader is referred to Voorhis et al., the biology, taxonomy and ecology of an­ (1982), Epifanio et al., (1982), Maurer et chovies and sardines in the Gulf. Brittan al., (1982) and Bartels (1981) fo r recent (1966) described a small colJection of shore companion studies of the physical ocean­ zone fishes, while Bussing (1969) listed the ography, chemical oceanography, faroilies of the marine fishes of Costa Rica. megabenthic invertebrates, and fishes of the Erdman (1971) provided tife history infor­ Gulf of Nicoya. The thesis bv Bartels mation for 55 species of marine fishes with (1981) contíiins much of the raw data special emphasis on sharks, rays and jacks. analyzed in this study.

Leon (1973) studied the oc curren . and The purpose of this study is to describe distribution of marine fishes in thece upper the occurrence, distribution, abundance and and middle Gulf. He reported dominance of diversity of demersal fishes in the Gulf of the upper Gulf by s ciaenids in terms of Nicoya and to attempt to defme sorne of

75 76 REVISTA DE BIOLOGIA TROPICAL the factors responsible for these findings. season gene rally occurs from May through This research was approached with four ma­ November (Leon, 1973). Due to the sea­ jor objectives in mind. The first was to sonality of precipitation in this area, there classify the Gulf in to biologically functional are significant variations in the discharges of zones on the basis of physical character­ the rivers and streams (Peterson, 1960) istics (water temperature, dissolved oxvgen, which contribute to changes in salinity and depth, salinity, and the distance to the density distribution patterns (Voorhis et al., mouth of the GulO and the correlation of 1982). The increased rainfall and subsequent fish species occurrence with these physical runoff appear to contribute to increased parameters. The second objective was the nutrient and turbidity levels during the iden tification of seasonal and zonal differ­ rainy season, particularly in the upper Gulf ences in dominance, diversity and oc­ (Epifanio et al. , 1982). currence. A third objective was to identify The data used in this study were taken any day-night differences in species oc­ during three cruises in the Gulf of Nicoya. curren ce, diversity and dominance and the The first , February, 1979 consisted of 20 final objective was to identify anv juvenile­ collections from 17 stations (3 stations adult partitioning within the estuary. were duplicated as night stations). The sec­ ond cruise took place during July, 1979 The study was undertaken as part of a and consisted of 22 collections at 20 larger Sea Grant sponsored project designed stations (2 stations were duplicated as night to promote training, technological exchange stations). During April, 1980, a third cruise and preliminary research between the Uni­ consisted of 20 day stations. The location of Delaware and the University of versity of these stations (Fig. 1) was chosen to Costa Rica. Hopefullv, these effo rts will provide coverage of the majority of the help identify additional potential fisheries Gulf. The addition of Stations 19, 20 and for the people of Costa Rica and provide a 21, in the J uly and April cruises, was made stronger basis for fu ture management of to enhance the coverage of the upper gulf. fisheries resources. In particular, this study Collections were made at each of the will provide basic information conceming stations using a semi-balloon shrimp trawl the distribu tion of important fish species (30 ft head rope and 37 ft fo ot rope at and possible key factors which lead to the the mouth with 1 1/2 inch stretched mesh observed patterns of their distribution. #9 thread body and 1 3/8 inch stretched mesh #1 8 thread bag). The net was towed MATERIAL AND METHODS at 1-2 knots with the prevailing current for a period of 30 minutes. A cable length of The Gulf of Nicoya is located on the 5 or 6 to 1 (length to depth) was used to west coast of Costa Rica between the ensure that the trawl was fishing the Peninsula of Nicoya and the mainland bottom. If the net became fouled or faiÍed (longitude 850W and latitude 10�; Fig. to function properly the haul was repeated. 1). The gulf is approximately 80 kilometers All fish captured were sorted to species in length and 45 kilometers wide at its whenever possible. Identifications were the greatest width (near mouth). Mangrove responsability of López and Bussing, swamps fringe most of the upper Gulf whereas Bartels and Price accounted fo r the while steep, forested hills bound the lower ecological aspects of the study. Gulf. Fresh-water input -is dependent on Identifications were completed using three main rivers. The Río Tempisque flows voucher specimens for the fl ISt cruise and into the upper end (Fig. 1). This is the were done on board ship during the second largest river entering the gulf and drains and third cruises. These fish we re then mostly agricultural land (Blutstein et al. , measured (total length) to the nearest centi­ 1970). Two smaller rivers, the Río Barranca meter. Disk width was used instead of total and Río Grande de Tárcoles, enter the length fo r all skates and rays. If there were middle to lower gulf along its east coast. greater than 50 individual s per species, a 50 The west coast of Costa Rica is under individual subsample was measure d. the influence of seasonal rains. The wet Subsample and total samples were weighed BA R TEL S et al, ,' Fishes of the Gulf of Nieoya, Costa Rica 77

NlCARAGUA"� �' Ca""." COSTA RICA COSTA RICA ?oc.t i c Ocean �AM-;_ �

RIO 8::vronco

10 5 O ¡•• •• KILOMETERS

" " .: ;. :.:.� : 5 6 .,::: I'i�:': alieno , ,,' 10 Il 9 .i�,a Leooa 8 : ZONE /// : ......

a Cobo Blanco Golfo Cobo 8[00<;0 Golfo de Nicoya b de Nicoya

10 5 O 10 ,...... KILOMETERS

..: . , .�.. . ZONE /// ZONE /11

e Cabo Blanco Golfo Cobo Blanco Golfo de Nicoyo de Nicoya

Fig. la. Gulf of Nicoya, Central America : Location of stations for flsh survey, February and July 1979 and April 1980. fig. lb, Gulf of Nieoya, Central America : Separation of the Gulf into zones by mean s of Ward's Euelidean Distanee Cluster Analysis (February, 1979). fig. le, Gulf of Nieoya, Central Ameriea : Separation of the Gulf into zones by means of Ward's Euelidean Distance Cluster Analysis (July, 1979),

Fig. Id, Gulf of Nieoya, Central America : Separation of the Gulf into zones by mean s of Ward's Euelidean Distanee Cluster Analysis (April, 1980), to the nearest 0.1 kilogram using a grocery depth and distan ce to the mouth of the scale. For those species with greater than Gulf) were recorded during the cruise by 50 individuals, the number of individuals other researchers as another part of the In­ was calculated by extrapolating the number temational Cooperative Sea Grant Program t o w ei ght ratio of the 50 individual (University of Delaware/University of Costa subsample. Rica) and are reported elsewhere (Voorhis The physical oceanographic data (water et al. , 1982 and Epifanio et al. , 1982). t em pe ra tu re, salinity, dissolved oxygen, Hydrographic data used in this analysis 78 REVISTA DE BIOLOGIA TROPICAL

8 6 Stofion 3 N'15 4 10 2

Zone I 8 8 N '42 6 4 6 2

4 18

2

10

., "O 8 " " "> 6 '5 .: 4 'O 2 .8E z" 10 2

8 16

6 12 4 8

4

14 18 22 26 30 34 38 42 46 50 54 58 6 8 10 12 14 16 18 20 22 24 Tolol Lenglh Tolal Lenalh (cm) (cm)

Fig. 2. Gulf of Nicoya, Central America : Length Fig. 3. Gulf of Nicoya, Central America : Length distribution of Micropogoniasalti pinnis by zone. disuibution of Larimuspaci ficus by zone. were collected at each trawl station within those stations at which both night and day a meter of the bottom, which best re flects samples were taken, day-night differences in the physical environment from which the species occurrence and abundan ces were des­ fishes were collected. cribed. Also, length frequency distribu tions A nalysis of these data took several of selected species were used to identify forms . The Gulf was divided into zones potential partitioning of the gulf by adults using cluster analysis (Ward's Method and juveniles. The species selected were Euclidean Distance) of the physical data. those with a high number of individuals The occurrence of fish species was corre­ and a relatively large range of occurrence lated with these zones. This was done by withinthe estuary or those species with means of percent of occurrence (d stations potential commercial value. Determination presentj # stations per zone) within each of the stage of maturity of these fishes was zone (Salzen, 1957). The relative impor­ obtained from the literature. Seasonal dufer­ tance (dominance) of fish species within ences in length frequency distributions, in each zone and the Gulf was calculated terms of their position in the estuary, were using the Biological Index Value (BIV)* . also determined. The BN was calculated fo r both numbers Four diversity indices were calculated of individuals and biomass. The percent of (Dahlberg and Odum, 1970). These índices maximum BN was used in order to allow were calculated fo r each cruise (sample comparisons among the various zones. The period) and fo r each zone identified as part BN takes into account the number or of this study. The Shannon-Weíner Index weight of individuals per species and the (H'= log = the frequency of occurrence of that species i =L 1 p.1 1 e p. where p. 1 (Subrahmanyam and Drake, 1975). For proportion of individuals ín the ith species) was used to measure the "total" diversity )/ of these areas. This index is influenced by *BIV = species ranl< (wt. or # # of species. BA RTEL S et al. ,' Fishes of the Gulf of Nicoya, Costa Rica 79 species richness and the equitability of collected were used in this analysis. species abundance (Dahlberg and Odum, Correlation values obtained from this 1970; Pielou, 197 4). A species richness analysis should provide a starting point for index (D =[ -1] /108s: N, where N = the identifying what factors are important in number of individualsS and = the number determining the distribution of fishes within of species) was also calculatedS (McErlean, et the Gulf of Nicoya. al., 1973; Cain and Dean, 1976). This index reflects the changing number of RESULTS AND DISCUSSION species in relation to sample size. Lloyd Division of the Gulf into zones: the and Ghelardi's (1964) equitability index (E= Gulf of Nicoya was divide d into zones by s'/s where s= number of species and s' = cluster analysis (Ward's Euclidean Distance) number of species predicted by Mac{\rthur's of the "abiotic" data. The analysis was broken stick modeI) and Pielou's (1974) carried out using three combinations and/or evenness index (J= H'/Hmax = H'/H logé treatments of the data. These were as where H = when all species are follows: 1) use of all "abiotic" data equally abundant)Hmax reflect the evenness in (dissolved oxygen, water temperature, the distribution of species abundance. salinity, depth, distance to the ocean and The species richness index and the two fish bi omass/station) in nonstandardized evenness indices were used to evaluate the form, 2) all data in standardized form (to c a u s e s f o r fl u c t u a t ion sin the reduce the effect of the different units Shannon-Weiner Index. used to measure the various data), and 3) These diversity indices were used in an all data except fish biomass/station attempt to identify trends in fish ( standardized). distribution and the relative favorability of Final division of the Gulf was carried conditions for fish !ife at different locations out using standardized data without fish throughout the Gulf. Analysis of variance biomass/station. Standardized data were was calculated to determine any significant chosen because of the reduction in the differences in diversity among the seasons effect of data units on the clustering of and zones (Dahlberg and Odum, 1970; stations. The use of biomass was dropped Subrahmanyam and Drake, 1975). If because it is not a physical characteristic of seasonal or zonal statistical significance was the water column. Since these zones were found, Duncan's New Multiple Range Test to be defined on the basis of their physical was performed to determine the characteristics, fish biomass had no place in significantly different seasons or zones the clustering process. (Subrahmanyam and Drake, 1975). Using these standardized data, the Possible relationships among physical stations within the Gulf were divided into properties of the Gulf and the occurrence two to five clusters. It was decided to of fish species in those areas and among divide the Gulf into three zones because it the fishes themselves were identified by produced the most reasonable and using two measures of correlation. These manageable division of the Gulf and the were Spearrnan's Rho and Kendall's Tau use of more than three zones produced (both non-parametric). · These measures of occasional singular, isolated stations as correlation use rankings of the variables zones. The three zones/ cruise o btained fit instead of absolute values and produce ' reasonably well with the anticipated division values between -1 and +1 which represent of the Gulf by observation and froID strongly negative and strongly positive previous studies (Leon, 1973; Stevenson, correlation between variables, respectively 1979). The relative size and position of the (Conover, 1971). Correlation coefficients zones fluctuates according to the and their level of significance were hydrography of the bay at the time of the calculated for species which are ranked cruise. highly in terms of number, biomass, percent Usted below are the stations found in occurrence and/or BIV. These species were each zone for the three cruises. This correlated with the physical data as well as division will be used throughout this study with each other. Numbers of individuals whenever zones are mentioned (Figs. 2,3). 80 REVISTA DE BIOLOGIA TROPICAL

TABLE 1

Gulfof Ni coya, CentralAmerica. Scientific,commo n and local (Spanish) names*of fishes collected during the three cruises (February and Ju ly 19 79 and Apri1 1980)

ScientificClassification CornrnonNarne Local Narne

CHONDRICHTHYES Carcharhinidae Sharks Tiburones

Mustelus sp. Srnoothhound

Dasyatidae Stingrays

Dasyatis longus Stingray Raya

Raji dae Skates Raja velezi R. equatorÜ1lis Raya R. sp. Raya

Rhinobatidae Guitarfishes

Zapteryx exasperata Banded guitarfishes

Torpedinidae Electric rays

Na rcine entemedor Electric ray

Urolophi da e Stingrays Rayas de espina

Urolophus halleri Round stingray Urotrygon aspidurus chilensis U. mundus U. serrula sp. U. OSTEICHTHYES

Antennariidae Frogfishes

Antennariusav alonis Roughjaw frogfish Zanahoria

Apogonidae Car dina lfishes

Apogon do vii Ca rdena l Ariidae Sea catfishes Bagres, cuminates

Arius dasycephalys Sea catfish Curninate A. furthii A.jordani A. seemani A. steindachneri A. sp. A. sp. 2 Netumapla typogon Bagre SCÜ1deichthystr oschelii Curninate colorado

Batrachoididae Toadfishes

Batrachoidesgilberti Toadfish Perro B. pacificum B. sp. Porichthys nautopaedium dship rnan Mi BARTELS et al. : Fishes of the Gulf of Nicoya, Costa Rica 81

Scientific classification Common name Local na me

Bothidae Left-eyedFlounders Lenguados

Azeviapanamensis Bothidae sp. Citharichthys gilberti Lenguado platophrys Cyc10C. psetta quema Flounder Lenguado C. st>o Engyophryssa nctUaurentii Etropuscrosso tus Fringed flounder Lioglossina tetraophthalmus Pseudorhombus dendritica Sya cium latifrons Flounder S. ovale Flounder Flounder sp.

Branchiostegidae Tilefishes

Caulolatilussp .

Carangidae Jacks and pompanos Jureles

Alectis ciliaris African pompano Caranx vinctus Jack Platanillo Chloroscombrusorqu eta Pacific bumper Bonito oj ón Hemicaranx leucurus Selene brevoortii Palometa S. oerstedii S. peruviana Pacific moonfish Palometa

Centropomidae Snooks Robalos

Centropomus armatus Snook Robalo nigrescens Snook Robalo C. Clupeidae Herrings Sardinas

Ilisha furthii Neopisthopterus tropicus Opisthonema bulleri Sardina O. libertate Thread herring Gallera O. sp. Ophisthopterusequato rialis

Congridae Conger eels

Hildebrandianitens

Cynoglossidae Tonguefishes Lenguados

Sy mphurusatr amentatus S. fa sciolarius S. melanurus S. sp. 1 S. sp. 2

Engraulidae Anchovies Anchoas

Anchoa eigenmannia A. ischana A. lucida Bocona A. naso A. panamensis 82 REVISTA DE BIOLOGIA TROPICAL

Scientificclassification Common name Localname

A. sp inifer A. starksi A. waIkeri Anchovia macrolepidota Cetengraulis mysticetus Anchoveta Bocona Lycengraulis poeyi

Ephippidae Spadefishes

Chaetodipteruszonatus Pacificspadefish Parapsettus panamensis Catecismo

Gadidae Cods

Physiculus nematopus

Gerreidae Mojarras (Gerrids) Palmitos

Diapterus aureolus D. peruvianus Pargo blanco D. sp. Eucinostomus argenteus E. gracilis Pacific flagfin mojarra Palmito

Gobüdae Gobies

Bollmannia chlamydes B. stigmatura Gobiodes peruvianus Gobionellu s liolepis Microgo biu s erectus

Grammistidae Soapfishes

Ryp ticu s nigripinnis Soapfish Jaboncillo

Kyphosidae Sea chubs

Kyphosus elegans Chub Vieja

Lophüdae Anglerfishes

Lophiodes caulinaris L. se tigerus

Lutjarúdae Snappers Pargos

Lutjanus colorado Pargo colorado L. guttatus Pargo de la mancha L. peru Hoplopagrusguenthe ri Pargo roquero

Mullidae Goatfishes

Pseudopeneus grandisquamis Bigscalegoa tfish Salmonete

Muraenesocidae Conger eels

Muraenesox coniceps Congrio Hoplunnis pacificus BARTELS et al. : Fishes of the Gulf of Nicoya, Costa Rica 83

ScientificcIassification Common name Local name

Muraenidae Moray eels Morenas

Gymnothorax dovii* Morena Priodonophus equatorialis

Ogcocephalidae Batfishes

Zalieutes elater Pez diablo

Ophich thidae Snake eels

Myrichthys tigrinus

Ophidiidae Cuskeels

Brotulacl arkae Lepophidiu m pardaIe Congrio moteado L.prorates Congrio plateado Ophidion sp.

Polynemidae Threadfins Bobo

Polydactylusappr oximans Blue bobo Bobo P. opercularis Yellowbobo Bobo

Pomadasyidae Grunts Roncadores (Haemulidae)

Anisostremus dov ii Grunt Cotón A. pacíficí Ha emulopsis ax illaris H. elongatus H. leuciscus Lulo H. nitidus H. sp. Orthopristis chalceus Corcovado Pomadasys macracanthus P. panamensis Viej a P. sp.

Sciaenidae Croakers and Drums Corvinas

Bairdiellaarma ta Croaker B. sp. Cyn oscion albus Corbina (CoIVina) Corvina reina phoxocephalus Corbina (CoIVina) Corvina picuda C. C. reticulatus Corbina (Corvina) Corvina rayada C. squamipinnis Corbina (Corvina) Corvina aguada stolzmanni Corbina (Corvina) Corvina coliamarilla C. C. sp. Corbina (Corvina) Elattarchus archidium Gallinita Isopisthus altipinnis Ojona Larimus acc1ivis Ñata L. argenteus Nata L. efftllgens Ñata L. pacíficus Ñata L. sp., Men tici"hus nasus Zorra M. panamensis Zorr a Micropogoniasaltipinnis Corvina agria Nebris occíden talis Corvina guavina

* Probably P. equatorialismisid�ntified at time of capture. 84 REVISTA DE BIOLOGIA TROPICAL

ScientificcJassification Common name Local name

Ophioscion imiceps Corvinachina O. sciera Corvina china O. typicus Paralonchurus dumerilii Corvina cinchada P. sp .

• Stellifer chrysoleuca . S. ericymba S. furthii S. illecebrosus S. mancorensis S. oscitans S. zestocarus S. sp.

Scorpaenidae Scorpionfishes

Scorpaena russula S. sp. l S. sp. 2

Serranidae Sea basses, groupers Meros

Cephaloph olis acanth istiu s Diplectrum labarum D. macropoma D. pacificum Menta Epinephelus niveotus Snowy grouper Mero Hemanthiasperuanus Splittail ooss Doncella Paralabrax humeralis Cabrilla Pronotogrammus eos

Soleidae Soles Lenguados

Achirusmazatla nus A. scutum Lenguado redondo A. sp. Trin ectesfimbriatus T. fo nsecensis T. sp.

Sphyraenidae Barracudas

Sphyraenaensis Sennet Barracuda

Stromateidae Butterfishes Palometas

Peprilus medius P. snyderi P. sp. Salema

Syngnathidae Seahorses & Pipefishes

Hippocampusingens Pacific sea horse Caballi to

Synodontidae Lizardfishes Garrobos

Synodus evermanni Lizardfish Picuda S. sc ituliceps lizardfish Picuda

Tetraodontidae Puffers Timboriles

Sphoeroides annulatus Timboril S. furthii S. kendalli BAR TEL S et al. : Fishes of the Gulf of Nicoya, Costa Rica 85

Scientificclassif ication Common name Local name

S. lobatus Timboril S. sechurae S. sp. 1 S. sp. 2

Trichiuridae Cutlassfishes

Trichiurusnitens Pacific Cutlassfish Cinta

Triglidae Sea robins Cabros

Prionotus albirostris Cabro P. gymnostethus P. horrens Cabro P. ruscarius Cabro P. stephanophrys Lumptail sea robin P. sp. 1 P. sp. 2

Note: Commonand local names compiled fr om Erdrnan (1971), León (1973 ), a list ofcom monand scientific namesof fishes from The United Sta tes and Cana da (1980), Fuentes and Araya (1979), Madrigal (1979) and Stevenson and Víquez (1978).

TABLE 2

Gulf of Nicoya, Central A merica: Top twenty species of fishes, ra nked by percent occurrence (%OC)fo r each ofth e three cruises (February and July 1979 and Apri1 1980)

Cruise Cruise Cruise III Species1 % OC Species11 % OC Species %OC

Synodu s sci tuliceps 70 Symphurus sp. 59 Synodu s sc ituliceps 65 Prionotus horrens 55 Sphoeroides furthii 59 Neopisthopterus tropicus 60 Porichthys nautopaedium 50 Prio notus horrens 59 Diplectrum pacificum 60 Cyclopsetta quema 40 Syacium ovale 55 Sph oeroides furth ii 60 Syacium ovale 35 Neopisthopterus tropicus 55 Prio notus horrens 60 Lepophidiu mprorates 35 Synodu s scituliceps 55 Porichthys nautopaediu m 55 Micropogoniasaltipinnis 35 Diapterus aureolu s 45 Sy mphurus sp . 50 Diplectrumpacific um 35 Porichthys nau topaedium 41 Stellife r illeceb rosus 45 Sph oeroides furthii 35 Symphurusmelanurus 41 Syacium ovale 50 Selene peruvianus 30 Stellife r zestocarus 41 Cyclopsetta sp. 40 Sy mphurus sp. 30 Diplectrumpaci ficum 41 Anchoanaso 40 Priodonophus equatorialis 30 Achirus scutum 41 Priodonophus equ atorialis 40 Zalieu tes elater 30 Cyclopsetta qu ema 36 Lepophidiu m prorates 40 Brotula clarkae 25 Eucinostomus gracilis 32 Diapterusaure olu s 35 Polydactylus. approximans 25 Muraenesox coniceps 32 Bollmannia chlamydes 35 Engyophrys sanctilaurentii 20 Polydactylusapproximans 32 Anisostremus dovii 35 Lioglossina tetraophthalmus 20 Isopisthus rem ife r 32 Muraenesox coniceps 35 Bollmannia chlamydes 20 Stellife r oscitans 32 Cy noscion phoxocephalus 35 Muraenesox coniceps 20 Etropus crossotus 27 Stellife r zestocaru � 35 Raja velezi 20 Anchoa naso 27 Achirus scutum 35 Scorpaena russula 20 Diapterus peru vianus 27 Peprilus medius 35 A ch irus scutum 20 Bollmannia chlamydes 27 Stellife r furthii 27 86 REVISTA DE BIOLOGIA TROPICAL

tropicus (60%); the sea bass, Diplectrum Cruise Zones Stations pacificum (60%); the puffer, S. fu rthii 3, 12, 14, 15, 16, 17, 18 (60%); the midshipmen, P. nautopaedium 1 1979) 1 1, 2, 4, 9, 13 (Feb., II (55%); the S. 5, 6, 8, 11 flounder. ovale (50%); and III lO, the tongue fish, Symphurus sp. (50%). 14, 15, 16, 17, 18, 19, 20, 21 The top twenty species by weight, for (July,II 1979) 1 1, 2, 3, 9., 13 II 5, 6, 8, 4,11, 12lO, each cruise, are given in Table 3. The top III five species collected during the first cruise 14, 15, 16, 17, 18, 19, 20, 21 were the drum, Micropogonias altipinnis; the (AIIIpril, 1980) 1 1, 2 II catfish, Arius sp. ; the croaker, Stellifer 3, 4, 5, 6, 8, 9, 10, 11, 12, 13 III oscitans; the lizard fish, S. scituliceps; and Night stations were exc1uded from these the sea bass, D. pacificum. The top five zones and the analysis based on those species, by weight, collected during the zones. These stations were only completed second cruise consisted of the drum, during the February (8N, 9N, ION) and Ophioscion sciera; the catfish, Arius jordani; July (8N and ION) cruises. Due. to the lizard fish, S. scituliceps; the Conger differences in temperature and dissolved eel, Mu raenesox coniceps and the catfish, oxygen, these night stations tended to be Arius steindachneri. Top five species taken split from the day stations at the same during the third cruise were the catfish, A. locations. For this reason and the s teindachneri; the ray, Dasyatis longus; the inconsistency of the night sampling, the drum, Paralonchurus dumerilii; the croaker, night stations will be discussed separately. Stellifer zestocarus and the drum, M. altipinnis. In each of these cruises, two Species occurrence and abundance: A families provided the greatest portion of the total of 29,81 2 fishes were co11ected during fish biornass collected. These were the the three cruises: 6,441 fishes representing Sciaenidae (drums and cro akers) and the 107 species during the first cruise, the Ariidae (sea catfishes). second cruise produced 9,220 fishes and The top twenty species, bv number of 131 species, while 14,151 fishes reoresenting individual s, are given in Table 4. The top 125 species we re collected during the third five species taken during the first cruise cruise. A list of a11 species collected (214), were the midshipmen, P. nautopaedium; by family is located in Table l. flounders, Floundt:r sp.; the croaker, S. A top twenty species by percent zestocarus; the sea bass, D. pacificum and occurrence (% OC), fo r each cruise, are the anchovy, Anchoa panamensis. During given in Table 2. During the first cruise, the seC0ild cruise, the top five species only three species were co11ected grea ter consi�ted of four sciaenids (Cynoscion than or equal to 50% of the insampling s qu amzpmnis, Is op isthus remife r, Stellifer stations. These were the lizard fish, fu rthii and S. zestocarus) and the flounder, Sy nodus scituliceps (70%); the sea robin, S. ovale. The top five species taken during Prionotus horrens (55%); and the the third cruise were the croaker, S. midshipmen, Porichthys nautopaedium zestocarus; the midshipmen, P. (50%). Six species wer.e co11ected at greater nautopaedium; the catfish, A. steindachneri ; than or equal to 50% of the second cruise the flounder, Citharichthys platophrys and stations. These included the tongue fish, the goby, Bollmannia stigma tura. S y mp h urus sp. (59%); the pu ffe r, In order to obtain some indication of Sphoeroides fu rthii (59%); the sea rObin, P. the overall contribution, and possibly horrens (59%); the flounder, . Syacium ovale importance, of the various species which (55%); the herring, Neopisthopterus tropicus were collected, we combined the rankings (55%); and the lizard fish, S. scituliceps of the top twenty species by % OC, weight (55%). Eight species were collected in and number of individuals. The results of greater than or equal to 50% of the this procedure are listed in Table 5. The stations during the third cruise. These were top five species collected during the first the lizard fish, S. scituliceps (65%); the sea cruise were P. nautopaedium, S. scituliceps, D. rabin, P. horrens (60%); the herring, N. pacificum, Cyclopsetta quema (flounder) and BARTELS et al. : Fishes of the Gulf of Nicoya, Costa Rica 87

S. zestocarus. The top five species taken during top five with ties for both BIV values. P. the second cruise were S. scituliceps, S. ovale, nau topaedium, S. sdtuliceps, Priodonophus A. steindachneri, I. remife r and e squami­ equatorialis (Conger) and Peprilus medius pinnis. During the third cruise, the top five were among the top five, of both BIV species were S. zestocarus, A. steindachneri, P. values, in zone 111. For the en tire cruise as nautopaedium, Peprilus medius (butterfish) a whole, only S. scituliceps and Diplectrum and S. scituliceps. By combining the top twenty pacificum placed in the top five species species fo r each cruise, a cumulative ranking using both nu mbers and biomass BIV was constructed for the cruise periodo The top values. five species collected during this period were S. Partitioning of the Gulf by size classes: scituliceps, P. nautopaedium, S. zestocarus, A. Six species were found to display sorne steindachneri and D. pacificum. level of partitioning among size c1asses. These species were Micropogonias altip innis, Biological Index Values: Biological Index Values (BIV) were calculated using both Larimus pacificus, Cynoscion phoxocephalus, numbers of individuals and biomass for e albus, Stellife r zes tocarus and Sy nodus each zone within each cruise. The BIV scituliceps. These species were selected due values (% of maximum) of the top twenty to their importance in the loca l fishery or species, using numbers and biomass, for because of the wide range and relatively each zone of cruises 1, 11 and III are given large number of individuals collected (i.e., in Tables 10-12. S. scituliceps). Due to the small sample In zone I of the first cruise, S. size, the results given below are provided to scituliceps and P. horren s were ranked in demonstrate possible trends in spatial the top five species using both numbers distribution of the various size c1asses of and biomass as a basis for the BIV. In these species and should on1y be used as zone 11, three species were in the top five an indicator of future areas of study. using both BIV values. These were S. scituliceps, Symphurus sp. and e quema. S. Micropogonias altipinnis: Of the 100 fish scituliceps and P. nautopaedium were among co11ected, 23 over 46 cm in length were the top five species, in both BIV categ ories, taken below Puntarenas (zones 1, 11 and III in zone III. S. scituliceps, Sy mphurus sp. during the three cruises). Of those fish and e quema were ranked in the top five, measuring 34-46 cm (31 individual s), only in both BIV categories, when using the one was collected, in zone 1, aboye entire cruise as one zone. Puntarenas. The remaining 30 individuals In zone I of the second cruise, S. were taken in zone below the zestocarus and S. oscitans were ranked in Pun tarenas peninsula. Of the n, 46 individuals the top five by number and biomass. measuring less than 34 cm, on1y 14 were Sphoeroides fu rthii, S. ovale and from zone 11. The remaining 32 fish were Eucinostomus gracilis (mojarra) were among co11ected from zone I inc1uding 24 from the top five, in both BIV categories, within aboye the peninsula. Figure shows the zone 11. Amo�g the top five species by BIV for distribution of the size c1asses2 among the both numbers and biomass in zone III were S. three zones. Those fish from zone I that scituliceps and B. chlamydes. Sph oeroides were greater than 46 cm were collected fu rthii and Symphurus sp. we re ranked in the from stations 3 (c ruise 1) and 15 (cruise top five species in both BIV categories, when III). The only sample containing fish in a11 the entire Gulf was used as a single zone. three size" groups « 34, 34-46 and 46) > was . st'ation 2 of the thi td c tui s·e. ' In zone ' I of cruise 111, Cynoscion ,phoxocephalus and A. 'steindachneri were L'arimus pacificus: Of those fish ranked in the top . five using f both BIV measured (309), on1y 32 were" collected values.· In ' zbne 'lI, zestocarus, outside ( zone III. These were collectéd ' from S. M. altipinnis, Diapterus peruviimus, Cynoscion station 13 (zone 11) during 'tfie first cruise. albus, Stellifer illeeebrosús, Isopithus remifer The largest individilals were collected from and Diapterus aureolus were inc1uded in the stations 3 (cruise I1I) and 6 (cruises I and 88 REVISTA DE BIOLOGIA TROPICAL

TABLE 3

GulfofNicoya, CentralAmerica: Top twenty speciesoffish es ra nked by biomass fo r each of the three cruises (Feb ruary and July 19 79 a nd Apri1 l980)

Cruise I Cruise Cruise III 11 Biomass Biomass Biomass Species (kg) Species (kg) Species (kg) Micropogoniasaltipinnis 23.25 Ophioscion sciera 30.91 Arius steindachneri 95.95 Arius sp. 20.60 Arius¡orda ni 22.57 Dasyatis longus 68.85 Stellife r oscitans 19.50 Sy nodus scituliceps 20.28 Paralonchurus dumerilii 56.90 Synodusscituliceps 15.00 Muraenesox coniceps 14.78 Stellife r zestocarus 46.75 Diplectrum pacificum 12.40 Ariussteinda chneri 13.34 Micropogoniasaltipinnis 44.60 Porichthys nautopaedium 12.10 Stellifer fitrthii 12.51 Sciadeichthys troschelii 37.40 Stellifer sp. 10.90 Netuma platypogon 9.97 Ophioscion sciera 28.50 Stellifer zestocarus 7.75 Diplectrum pacificum 9.92 Muraenesox coniceps 25.60 Cyclopsetta quema 6.90 Syacium ovale 9.60 Urotrygon chilensis 20.60 Flounder sp. 6.75 Paralonchurus dumerilii 9.0 7 Porichthys nau topaedium 19.30 Polydactylusapprox imans 5·80 Achirus scutum 8.25 Stellifer fitrthii 18.55 Prionotusho rrens 5.76 Stellifer zestocarus 7.95 Stellifer chrysoleuca 16.35 Selene peruvianus 5.25 Cyclopsetta querna 7.92 Peprilusmedius 15.85 Priodon ophus equatorialis 5.05 Stellife r oscitans 6.85 Synodusscitu liceps 15.55 Lepophidu m prora tes 4.25 Ophioscion typicus 6.60 Menticirrhus nasus 9.00 Larimus pacificus 4.25 /sopisthus remife r 6.03 Eucinostomus argenteus 7.50 Lioglossina tetraophthalmus 3.75 Lepophidium prora tes. 5.84 Syacium ovale 7.25 Mu stelus sp. 3.50 Symphurus sp. 5.83 Cith arichthyspl atophrys 6.95 Ophioscion sciera 3.20 Stellife r chrysoleuca 5.65 Polydactylusapprox imans 6.35 Scorpaena russula 2.57 Micropogoniasaltipinnis 5.16 Cy noscion phoxocephalus 6.80

Total all fishes: 224.54 331.19 680.26

lB). These were the only stations length. There appeared to be a general containing relatively high numbers of scarcity of individual s in the 13-15 cm individuals measuring 16-22 cm. Also, only range. 8 of the 97 specimens measured less than 14 cm in these zones. Relatively large Cynoscion albus: Of the 217 individuals numbers of fish (98) measuring less than measured, only 37 were captured outside 10 cm were only collected during the third zone 1. These were taken at station 1 cruise (stations 4, 12 and 13). Stations 13 during the third cruise and ranged from 5 (cruise I) and 12 (cruise II) contained to 17 cm in length. There did not appear mostIy fish measuring 10-15 cm. Figure to be any dominant size group among provides a graphical demonstration of the3 them. Most of the fish lengths were spread size class distributions of L. 'pacificus at the relatively evenly between 7 and 14 to 15 various stations. cm.

Cy noscion phoxocephalus: C. Stellife r zestocarus: S. zestocarus were phoxocephalus were only captured during taken from all three zones. A total of 452 the third cruise. Only two individual s, of individual s were taken ranging from 3-19 211 total, were taken outside of zone 1. cm. The samples taken during the third These were taken at station 2 (zone 11). cruise contained fewer fish measuring less Fish measuring greater than 15 cm were than 8 cm (2 individual s) than those fish captured only at stations 2 (1 individual ), taken during the first two cruises (80 16 (14 individuals) and 18 (4 individuals). individuals). The majority of the fish The majority of the catch at each station measured (328 individuals) were found to consisted of fish between 6 and 12 cm in be between 10 to 13 cm in length. BAR TELS et a/. : Fishes of the Gulf of Nicoya, Costa Rica 89

TABLE 4

Gu/f of Nicoya, Centra/ America: Top twenty sp ecies of fish es ranked by number for each ofthe three cruises (February ami Ju/y 1979 and Apri1 1980)

Cruise Cruise Cruise III 1 11 Species # Species # Species #

POrichthys nau topaedium 1620 Cynoscion squamipinnis 915 Stellife r zestocarus 2146 F/ounder sp. 886 Isopisthus remife r 799 Porichthys nautopaedium 1895 Stellife r zestocarus 560 Stellife r furthii 775 Arius steindachneri 1747 Dip/ectrumpaci ficum 486 Syacium ovale 528 Citharichthys platophrys 792 Anchoa panamensis 375 Stel/ife r zestocarus 524 Bollmannia stigmatura 749 Bol/mannia stigmatura 300 Arius steindachneri 496 Neopisthopterus tropicus 460 Cyclopsetta quema 282 Achirusscutum 360 Pepri/us medius 419 Synodusscituliceps 238 Synodusscitu liceps 351 Cynoscion phoxocepha/us 390 Stellife r oScitans 236 Porichthys nau topaedium 339 Bol/mannia chlamydes 358 Scorpaena russu/a 207 Se/ene oerstedii 285 Sphoeroidesfurth ii 347 Stel/ife r furthii 157 Diapterusaureo/u s 283 Stellife r furthii 295 Prionotus horrens 157 Stellife r oscitans 265 Lepoph idium prorates 254 Cynoscion a/bus 133 Sp hoeroides furthii 238 Synodusscituliceps 254 Symphurussp. 131 Citharichthys platophrys 208 Cy noscion a/bus 25 3 Sph oeroides sp. 2 130 Engyophrys sancti/auren tii 187 Sciadeichthys troschelii 229 Sphoeroides furthii 128 Eucinostomus gra cilis 178 Urotrygon chilensis 215 Larimus pacificus 114 Neopisthopterus tropicus 176 Syaciumovale 207 Lepophidiu m prora tes 112 Ophioscion typicus 174 Symphurus sp . 196 Sphoeroides sp. 1 107 Dip/ectrum pacificum 173 Achirus scutum 190 Se/ene peruvianus 102 Symphurus sp. 158 Prionotus horrens 181

Total aH fishes 6441 9220 14151

Synodus scitu liceps: Ten statíons and distance to the ocean) during the first contained at least 28 individuals of this cruise (Table 17). Kendall's and Spearman's species. Of these, only station 12 (zone 1, correlations both yielded similar results with first cruise) was outside zone IlI. A total the exception of the correlation between of 390 individuals was measured from these Antennarius avalonis and the distance to stations. The fish lengths, from most of the the ocean. This correlation was not stations, demonstrated a bimodal significant to the .05 level using Kendall's distribution with very few individuals of Tau (.055) although it was significant using int ermediate size. The first peak was Spearman's Rho (.034). Throughout these generally located between 8 and 15 cm analyses, Spearman's Rho was consistently with the second peak between 18 and 28 higher than Kendall's Tau. cm. Stations (frrst cruise) and 8 (second The occurrence of A. avalonis was 6 c TU ise) did not have the lower peak. negatively correlated with high dissolved Station 9 (third cruise) did not have a oxygen levels (DO), temperature and large peak for larger individual s, . Also, station 11 distances from the ocean and was positively (second cruise) had only one broad peak correlated with increasing depth. Achirus located between 14 and 22 cm. Table 14 scu tum dist ributions were negatively provides the length distribution fo r S. correlated with increasing depth and salinity scituliceps. while being positively correlated with increasing temperature and distance from Correlation analysis: The abundances of the ocean. S tell ife r oscitans and S. six species were found to be significantIy zestocarus distributions were positively ( > .05) correlated to one or more of the correlated to increasing distance from the physical properties of the Gulf (salinity, ocean. The occurrence of Priodonophus dissolved oxygen, water temperature, depth equatorialis was positively correlated to 90 REVISTA DE BIOLOGIA TROPICAL

TABLE 5

Gulf ofNicoya. Central America: Top twenry species per cruiseas measured by che;, total combined rank (n umber, hiomass ond %occurrence).

Cruise 111 Cumulative Cruise 1 Cruise II Rank Species Rank Species Rank Species Rank Species

Porichthys nau topaedium Sy nodus scituliceps Stellifer zestocam s Synodusscituliceps Synodus scituliceps Syocium ovale Arius steindachneri Porichthys nautopoedium Diplectrum pacificum Arius steindachneri Porichthys nautopaedium Stellifer zestocoro s Cyc/opsetta quema lsop isth us rem ifer Peprilus medius Arius steindachneri Stellifer zestocarus Cylloscion squamipinnis Syn odusscituliceps Diplectrum pacificum Stellife r oscitans Ophioscion seiera Neopisthopterus tropicus Stellifer furthii Flounder sp. An"us jordan; Sciadeichthys troschelii Stellifer oscitans Prionotus horrens Dip lectrum pacificum Cilh arichlhys plalophrys Syacium ovale Arius sp Stellifer [urthii Micropogoniasaltipinnis . Stellifer [urthii Anchoa panamensis Porichthys nautopaedium Dasyatis longu s Ophioscion seiero Bollmannia ch/amydes Stellife r oscitans Para lonchurus dumerilii Peprilu s medius 9 Bollmannia stigmatura 10 Sphoeroides [urthii Sphoeroides fu rth ii Isop isth us remifer 10 Scorpaena russula Diapterus aureolu s Urotrygon chilensis Muraenesúx coniceps 11 Se/ene peruvianus 11 Achirus seulUm 10 Bo/lmallnia stigmatura Sphoeroides ¡Urthii Polydactylus approximans Netuma platypogo n Micropogoniasaltipinllis Cyclopsetta quemo 12 Lepoph idium prorates 12 Stellifer zestocam s 11 Cy nosclon phoxocephalus Cy noseion squomipinnis Symphurus sp. 13 Symph urus sp. 12 Muroenesox cOlliceps Neopisthopterus tropicus Priodoll op hus equatoritllis 14 Cyclopsetto quema Ophioscion seiera Scia delchthys troschelii Slelli!e, furthii Se/ene oerstedii 13 Bol/monilla chlamydes 10 Bollmannia stigmotura Paralonchurus dumerilli 14 Syacumi ovale Citharichthys p/atophrys

increasing salinity. The occurrence of A rius steindachneri and Cynoscion Bro tula clarkae was negatively correlated phoxocephalus were negatively correlated to with increasing DO levels. Table 18 contains increased temperature and distance from the the correlation coefficients and their level ocean. The occurrence of Trinectes sp . was of significance for the fi rst cruise positively correlated to increasing species-species correlations. temperature and distance from the ocean. The abundances of four species were The distribution of Cynoscion albus found to be significantly correlated(.05) to demonstrated a positive correlation with the one or more of the physical properties of distance to the ocean. S. scituliceps and the Gulf during the J uly cruise (Table 19). Symphurus atramen tatus distributions were The occurrence of Sy nodus scituliceps was negatively correlated to increasing negatively correlated to high DO, temperature and distan ce to the ocean. S. t emperature and large distances to the scituliceps and Symphurus atramen tatus ocean and demonstrated a significant distributions were negatively correlated to positive correlation with increasing depth increasing temperature and distance to the and salinity. The occurrence of Arius ocean. steindachneri was negatively correlated to Table 22 contains the correlation increasing depth and positively correlated coefficien and their significant values for wi t h t he distance to the ocean. The the thirdts cr uise species-species correlations. distribution of A. scutum demonstrated a F orty-eight species pairs were significantly negative correlation with increasing depth correlated (.05). Of these correlations, six and a positive correlation with the distan ce were only significant using Spearman's to the ocean. The oc curren ce of Arius · correlation. Six of the fo rty-eight pairs were jordani was positively correlated to the negatively correlated. distance from the ocean. Table 20 contains Leon 's (1973) study extended only to a the correlation coefficients and their line between the Río Grande de Tárcoles significance levels ( ';;;; .05) for the second a n d N egritos Afuera and included cruise species-species correlations. approximately nine, predomina ntly The abundances of nine species were near-shore, stations below zone 1 of this significantly correlated (.0 5) to one or more study. Only three of these stations were of the physical properties of the Gulf part of zone III of this study (only for during the third cruise (Table 21). The cruise I1I). Leon tound a large de crease in occurrence of A. scutum, Sy mphurus sp., the frequency of occurrence of the catfishes BARTEL S et al. : Fishes of the Gulf of Nicoya, Costa Rica 91

TABLE 6

Gulf of Nicoya, Central America: Top twenty fish species in terms of B/ V (number and biomass) for Cruise / (February 1979).

% Maximum % % Maximum Species BIV (Number) Species BIV (Biomass)

Prionotus horrens 62.150 Synodus scituliceps 44.840 Synodusscituliceps 61.710 Cyclopsetta quema 33.127 Cy clopsetta quema 39.637 Symphurussp. 32.301 Porichthys nautopaedium 39.555 Micropogoniasaltipinnis 28.793 Symphurussp. 39.445 Selene peruvianus 26.987 Sphoeroides filrthii 37.658 Prionotus horrens 26.5 74 Selene peruvümus 33.645 Polydactylusappro ximans 22.601 Micropogoniasaltipin nis 32.875 Porichthys nautopaedium 17.441 Diplectrum pacificum 27.900 Diapterusperuvianus 16.7 18 Lioglossina tetraophalmus 27.460 Syaciumovale 15.893 Polydactylus approximans 27.295 Diplectrum pacificum 15.015 Syacium ovale 22.677 Stellife r zestocarus 11.662 Lepophidiu m prorates 22.430 Stellife r sp. 11.662 Zalieutes elater 22.402 Stellife r oscitans 11.662 Achirus scutum 21.853 Flounder sp. 11.5 58 Antennarius avalonis 21.495 Lepophidium prorates 11.507 Priodonophus equatorialis 21.385 Larimus pacificus 11.3 52 Muraenesox coniceps 21.193 Priodonophus equatorialis 11.3 52 Bollmannia chlamydes 17.097 Achirus scutum 11.249 Flounder sp. 17.042 Lioglossina tetra ophthalmus 11.042 /sop isthus altipinnis 11.042

TAB LE 7

Gulf ofNico ya, Central America: Top twenty fish species in terms of B/ V (numberand biomass) fo rcruise (Ju ly 1979) 11 % Maximum % Maximum Species BIV (Number) Species BIV (Biomass)

Sphoeroides filrthii 61.622 Symphurus sp. 45.588 Prionotus horrens 55.782 Synodusscituliceps 42.892 Neopisthopterus tropicus 55.706 Sphoeroides filrthii 40.368 Symphurussp. 55.5 15 Stellife r zestocarus 36.985 Syacium ovale 47.137 Muraenesox coniceps 34.191 Sy nodus scituliceps 46.870 Syacium ovale 32.206 Diapterusaureolu s 46.775 Stellife r oscitans 31.103 SJellifer zestocarus 43.302 Prionotus horrens 30.564 Achirus scu tum 41.126 Arius jordani 28.554 Porichthys nau topaedium 37.023 Stellife r fu rthii 28.529 /sopisth us remifer 34.237 Paralonchurus dumerilii 28.431 Diplectrumpacificum 32.786 /sopisth us remife r 28.284 Symphurusmelan urus 32.500 Polydactylus approximans 27.696 Stellife r oscitans 32.500 Achirus scutum 26.985 Polydactylusappro ximans 31.164 Diapterusaureolu s 24.265 Muraenesox coniceps 30.420 Diapterusperuvianus 23.309 Eucinostomus gracilis 28.740 Porichthys nautopaedium 23.260 Stellife r filrthii 28.492 Symph urusmelanurus 22.132 Arius jordani 27.901 Ophioscion sciera 19.363 Paralonchurusdume rilii 27.7 86 Eucinostomus gracilis 19.314 92 REVISTA DE BIOLOGIA TROPICAL

TABLE 8

Gulf of Nicoya, Central America: Top twentyfish spec ies in termsof B/V (number and biomass) fo r cruise/JI (A priI 1980)

% Maximum % Maximum Species BIV (N umber) Species BIV (Biomass)

Synodu s scituliceps 60.800 Synodus scituliceps 51.989 Neopisthopterus tropicus 56.140 Syacium ovale 45.739 Sphoeroides furthii 55.480 Porich thys nau topaedium 43.239 Prionotus horrens 55.020 Diplectrum pacificum 40.824 LJiplectrumpaci ficum 53.700 Symphurussp. 39.574 Porichthys nautopaedium 53.34 Prionophus equatorialis 36.960 Syacium ovale 47.5 20 Stellife r illecebrosus 35.7 95 Sy mphurus sp. 45.960 Prio notus horrens 35.284 Stellife r illecebrosus 41.700 Muraenesox coniceps 33.608 Anchoa naso 36.880 Peprilus medius 32.756 Lepophidiu m prorates 36.200 Cynoscion phoxocephalus 31.222 DitJpterusaureolu s 36.160 Paralonchurus du merilii 29.233 Priodonophus equatorialis 36.000 Microp ogoniasalti pin nis 28.381 Cyclopsetta sp. 35.660 Arius steindachneri 27.699 Cyn oscion phoxocephalus 33.640 Lepophidiu m prorates 27.670 Stellife r zestocarus 32.980 Stellife r zestocarus 26.705 Peprilus medius 32.960 Neopisthop terus trop icus 26.080 Bollmannia chlamydes 32.880 Sciadeichthys troschelii 23.920 Achirus scutum 32.620 Polydactylusappro ximans 23.267 Muraenesox coniceps 30.5 20 Menticirrh us nasus 22.926

and a general decrease in dominance by 14, 12 and ten kilometers west of 3, and any single group in this lower gulf area. do not cover much of the deeper water The present study found that although the located in the center of the Gulf. Sampling, sciaenids were the most dominant group, in the present study, was in tended to cover they were collected at fewer stations than both near-shore and deep-water areas. The in Leon's (1973) study. The down-bay trawls in . Leon's study were twice as wide decline in catfish abundance was similar to at the mouth (20 meters) had larger mesh that described by Leon (1973). Syacium (5 cm) and were towed twice as long (one ovale and Priono tus horrens were common hour) as the trawls in this study. inhabitants of this area in both studies. Sorne seasonal (cruise versus cruise) However, two species collected at greater differences were observed. More species per than 50% of Leon 's stations (Lycengraulis station were collected at more stations poeyi [anchovy] and Vomer declivifrons during the third cruise than during the first [carangid]) were rare (collected at 2 of ·27 (9 of 14) or second cruises (11 of 20). stations) or absent, respectively, from our Third cruise stations also provided the collections. Also, N. tropicus, Sy mphurus highest biomass per station when compared sp. and Sp hoeroides fu rthii were collected with the ru st (13 of 14) and second at greater than 50% of the stations within cruises (16 of 20). These results were this area by us while only Symphurus sp. probably due to the increase in the number and S. fu rthii were taken at greater than and weight of cat fish caught in the upper 20% but less than 49% by Leon. The Gu 1f and the incre ase in biomass differences between these studies, for the contributed by sciaeni ds (especially mid-Gulf area, may be due to the Micropogonias altipinnis and Stellifer differences in sampling patterns and gear zestocarus) in the mid-Gulf, during the size . Leon's mid-Gulf stations were clustered third cruise. Any seasonal (wet season around fOUT main areas, near our stations 1, versus dry season) causes for these results BA RTELS et al. : Fishes of the Gulf of Nicoya, Costa Rica 93

TABLE9

Gulfof Nicoya, Central America: Distribution of lizard fish (Synodus scituliceps) lengths (cm) fo r all stations with greater than25 individuals collected (1 979-1980)

L.ength in cm Cruise Station Number 10 II 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 >32

12

11 111

11 12

TABLE I0

Gu lf of Nieoya, Central America: Correlation coeff icients and level of significance fo r Kendall's and Sp earman 's rank-order eorrelation of species vs physieal parameters fo r cru ise (February 1979) 1

Kendall's Tau Spearman 's Rho Species Phy sical Pararneter Coef. Signif. Coef. Signif.

Antennarius avalonis Dissolved Oxygen -0.4709 0.022 -0.5 937 0.01 2 Bollmannia ehlamydes Dissolved Oxygen -0.4594 0.025 -0.5516 0.022 Achirus seu tum Depth -0.5 202 0.01 2 -0.6304 0.00 7 Antennariusava lonis Depth 0.4548 0.028 0.5881 0.01 3 Aehirusseu tum Temperature 0.4589 0.025 0.5454 0.024 Antennariu s avalonis Temperature -0.4860 0.018 -0.6312 0.007 Aehirus scu tum Salinity -0.5065 0.026 -0.5716 0.017 Priodonophus equatorialis Salinity 0.5109 0.025 0.5518 0.022 Aehirusseu tum Dist. to Ocean 0.5306 0.01 1 0.6573 0.004 Antennariusavalonis Dist . to Ocean -0.4044 0.055 -0.5 148 0.034 Stellife r oscitans Dist. to Ocean 0.4355 0.043 0.4953 0.043 Stellife r zestocarus Dist. to Ocean 0.4355 0.043 0.5218 0.032 are highly dou btful. During the first cruise, During the three University of three species (D_ aureolus, A. naso and N. Delaware/University of Costa Rica research tropicus) which were found in large cruises in the Gulf of Nicoya, Costa Rica, numbers in the other cruises were rarely 29,812 fishes representing 214 species were colle c ted. Meanwhile, Cynoscion collected. The sciaenids (drums and phoxocephalus was only taken .during the croakers) and sea catfishes (Ariidae) were third cruise. There was no apparent reason most important in terms of biomass. for the se results. AIso, the catfishes S te /lifer zestocarus (croaker), Po richthys surpassed the sciaenids in number in the nau topa edium (midshipmen) , several upper Gulf, during Cruise III. In fact, flounders and catfishes contributed the sciaenid abundance levels were generally greatest numbers of individuals. The top down throughout their range (except S. five species ranked by their combined illecebrosus and S. zestocarus) during this biomass, numerical abundance and percent cruise. Reasons fo r this observation are occurrence were Sy nodus scitu liceps (lizard unc1ear due to the limited time period of fish), P. nautopaedium, S. zestocarus, Arius this study. steindachneri (catfish) and Diplectrum 94 REVISTA DE BIOLOGIA TROPICAL

TABLE 11

Gulf of Nicoya, Central America: Correla tion co efficients and significance levels ("'0. 05) fo r Kendall'sand Sp earman 's rank-order correlation of species vs species fo r cruise (February 1979) 1 Kendall's Tau Spearman's Rho Species Coef. Signif. Coef. Signif. Species

Achirus scu tum Diplectrum pacificum 0.5252 0.028 0.5485 0.023 A. scutum Stellife r zestocarus 0.6839 0.004 0.7055 0.002 A. scutum Synodusscituliceps -0.4213 0.045 -0.4887 0.047 Anchoa panamensis Scorpaena russula 1.000 0.001 1.000 0.00 1 Antennarius avalonis Priodonophus equatol'Úllis 0.4967 0.043 A. avalonis Prionotus horrens 0.5298 0.028 0.5491 0.022 Arius sp. Diplectrum pacificum 0.6286 0.01 1 0.6378 0.006 Bollmannia stigmatura Sph oeroides sp. 1.000 0.001 1.000 0.001 Diplectrum pacificum Stellife r júrthii 0.7184 0.004 0.7289 0.001 D. pacificum Stellife r zestocarus 0.7184 0.004 0.7289 0.001 Flounder sp. Stellife r júrthii 0.6286 0.01 1 0.6378 0.006 Flounder sp. Stellife r oscitans 0.6286 0.01 1 0.6378 0.006 Priodonophus equatorialis Synodusscitu liceps 0.5950 0.005 0.6816 0.003 Selene peruvianus Stellife r oscitans 0.7184 0.004 0.7289 0.001 S. peruvianus Stellife r zestocarus 0.6286 0.011 0.6378 0.006 Stellife r júrthii S. zestocarus 0.4839 0.046 0.5000 0.04 1 Stellife r oscitans Symphurussp. 0.4194 0.025 0.5438 0.024

TABLE 12

Gulf of Nicoya, Central America: Correla tion coefficients and level of significance for Kendall's and Sp eaiman's rank-order correlation ofspecies vs. physical pa rameters fo r cruise JI (July 1979)

Kendall's Tau Spearman's Rho Species Physical Parameter Coef. Signif. Coef. Signif.

Synodus scituliceps Dissolved Oxygen -0.4692 0.007 -0.6344 0.003 Arius steindachneri Depth -0.4569 0.015 -0.5404 0.014 Achirus scutum Depth -0.4111 0.022 -0.5492 0.012 SY llodus scituliceps Depth 0.4901 0.005 0.6192 0.004 Synodu s scituliceps Temperature -0.4204 0.021 -0.5219 0.018 Sy nodusscitu liceps Salinity 0.4711 0.012 0.5837 0.007 Achirus scu tum Dist. to Ocean 0.5944 0.7379 0.001 Arius jordani Dist. Ocean 0.5193 0.006 0.61 75 0.004 to Arius steindachneri Dist. to Ocean 0.5873 0.002 0.6819 0.001 Synodu s scituliceps Dist. to Ocean -0.6110 0.001 -0.7 166 0.001 pacificum (sea bass). In terms of Biologieal most important speeies eolleeted in the I ndex Value (BIV), S. scituliceps, P. Gulf nau topaedium, D. pacificum, Syacium ovale The Gulf of Nieoya was divided into (flounder), Prionotus horrens (sea robin) three zones, for eaeh eruise, on the basis and Sy mphurus sp. (tonguefish) were the of physieal data taken at eaeh station BA RTELS et al. : Fishes of the Gulf of Nicoya, Costa Rica 95

TABLE 13

Gulf of Nieoya, Central Ameriea : Correlation eoefficients and level ofsignifieanee (.;;; 0. 05) for Kendall's and Spearman's ra nk-order eorrelation of species vs speciesfo r eruise (Ju ly 1979) 11

Kendall's Tau Spearman's Rho Species Species Coef. Signif. Caef. Signif.

Aehirus seu tum Arius¡ordani 0.6266 0.002 0.7 204 0.001 A. seutum Arius steindaehneri 0.5326 0.009 0.5752 0.008 A. seutum Syacium ovale -0.4 223 0.026 -0.5114 0.021 A. seu tu m Sy nodus seitulieeps -0.5388 0.005 -0.6512 0.002 Arius ¡o rda ni Prionotus horrens 0.4403 0.042 0.4663 0.038 A. ¡ordani Synodusseitu lieeps -0.5051 0.010 -0.5949 0.006 Arius steindaehneri Polydaetylusappro ximans 0.5210 0.018 0.5407 0.014 A. steindaehneri Prionotus horrens 0.4661 0.035 0.4837 0.03 1 A. steindaehneri Syaeium ovale -0.2984 0.045 -0.4599 0.04 1 A. steindaehneri Symphurus sp. 0.4063 0.037 0.4787 0.03 3 A. steindaehneri Synodusseituli eeps -0.3984 0.045 -0.4599 0.04 1 Diapterusaureolu s Paralonehurus du merilii 1.000 0.001 1.000 0.00 1 Dipleetrum pacifieum Isopisthus remife r 1.000 0.00 1 1.000 0.00 1 Neopisthop terus tropicus Cy noseion squamipinnis 1.000 0.00 1 1.000 0.00 1 Netu ma platypogon Stellifer oscita ns 1.000 0.001 1.000 0.001 Ophioscion sciera Poriehthys nau topaedium 1.000 0.001 1.000 0.001 O. seiera Sphoeroides furthii 1.000 0.001 1.000 0.001 Poriehthys nautop aedium Sphoeroides furthii 1.000 0.00 1 1.000 0.001 Syacium ovale Synodussc itulieeps 0.4 722 0.01 1 0.5752 0.008 Polydaetylus approximans Symphurusmel an urus 0.4435 0.050

(water temperature, depth, salinity, dissolved abundances. These included S. scituliceps, S. oxygen and distance from the mouth of ovale, P. horrens, Sy mphurus sp. and the the GuIO. Little change in the position of herring, Neopisthopterus tropicus. Other these zones, during the study period, was species were restricted to either the upper observed. The distribution of fish species ( warm, shallow) or lower (cool, deep) within the zones remained relatively portions of the Gulf with sorne mixing constant. No significant seasonal changes the mid-Gulf area. Dominant groups and speciesin number, biomass, percent occurrencein, in the upper Gulf include sciaenids, sea diversity or partitioning by .size class of catfishes, flatfish (soles, tonguefish and S. fishes were observed. ovale), Sp hoeroides furthii (puffer), P. horrens Night stations had gene rally higher and tropicus. The lower Gulf displayed less biomass and more species than those same dominanceN. by only a few groups than the upper stations during daylight. Five species were Gulf. Flounders (S. ovale, Cyclopsetta sp . and c ollected predominantIy at night. These C. quema), gobies (Bollmannia chlamydes and were Brotula clarkae (goby), Lepophidium B. stigma tura), morays (H. nitens, Priodo­ prorates (cuskeel), Raja velezi (skate), nophus equatorialis and Muraenesox coniceps), Scorpaena russula (scorpion-fish) and Sy mphurus sp., S. scituliceps, P. nautopaedium, Hildebrandia nitens (moray eel). Diapterus aureolus (mojarra), Antenarius Two maj or types of distributional avalonis (frogfish), D. pacificum and Larimus patterns were observed. Several species were pacificus (drum) were collected primarily in the found throughout the Gulf in varying lower Gulf. 96 REVIST A DE BIOLOGIA TROPICAL

TABLE 14

Gulf of Nicoya, Ce ntral America: Correlation coeffic ients and level of significance fo r Kendall 's and Spearman's rank-order correlation ofspecies vs. physical parametersfo r cruise (A priI 1980). IJ! Kendatl's Tau Speannan's Rh o Species Physical Parameter Coef. Signif. Coef. Signif.

Achirus scu tum Depth -0.5883 0.001 -0.7489 0.001 Arius sfeindachneri -0.5736 0.002 -0.6730 0.001 Cynoscion phoxocephalus -0.3922 0.03 1 -0.5365 0.01 5 Symphurus sp. -0.4153 0.019 -0.5 123 0.021 Trin ectes sp. -0.3618 0.05 2 -0.4749 0.034 Achirus scu tum Temperature 0.5742 0.00 2 0.7078 0.001 Arius steindachneri 0.6185 0.00 1 0.6860 0.001 Cynoscion phoxocephalus 0.4652 0.013 0.6051 0.005 Symph urus atramentatus -0.5538 0.004 -0.6476 0.002 Symphurussp. 0.4117 0.024 0.5168 0.020 Synodusscituliceps -0 .5000 0.005 -0.6122 0.004 Trinectes sp. 0.4923 0.010 0.5846 0.007 Achirusscutum Dist. to Ocean 0.6392 0.001 0.8048 0.001 Anisostremus dovii 0.3869 0.040 0.4652 0.039 Arius steindachneri 0.6346 0.00 1 0.7803 0.001 Cynoscion albus 0.5544 0.003 0.6447 0.002 Cynoscion phoxocephalus 0.6534 0.00 1 0.8012 0.001 Symphurus atramentatus -0.5085 0.007 -0.6173 0.004 Sy mphurus sp. 0.6 160 0.001 0.7351 0.001 Synodus scituliceps -0.4479 -0.5 728 0.008 omo Trinectes sp. 0.6033 0.001 0.6935 0.001

TABLE 15

Gulf of Nicoya, Central America: Corre/ation coefficientsand level of significance (.;;0.05) for K endall's and Spearman 's ra nk-order correlation of species vs species fo r cruise ( Apri1 1980) JI! Kendall's Tau Spearman's Rho Species Species Coef. Signif. Coef. Signif.

Achirus scutum Anisostremus dovii 0.5966 0.003 0.6473 0.002 A. scutum Antennarius avalonis -0.4115 0.045 -0.4595 0.042 A. scutum Arius steindachneri 0.8072 0.001 0.9213 0.001 A. scutum Cy noscion albus 0.5022 0.01 3 0.6192 0.004 A. scutum Cynoscion phoxocephalus 0.7143 0.001 0.8551 0.00 1 A. scutum Porichthys nau topaedium 0.4435 0.050 A. scutum Symphurussp. 0.51 36 0.008 0.61 89 0.004 A. scutum Stellifer mancorensis 0.4435 0.050 A. scutum Synodus scituliceps ' -0.4022 0.031 -0.4 727 0.035 A. scutum Trin ectes sp. 0.5637 0.005 0.6540 0.002 A. scutum Urotrygon chilensis 0.4435 0.050

Anchoa naso DiapterusaUreolu s 0.4344 0.027 0.4890 0.029

Anchoa walkeri Cynoscion albus 0.4815 0.026 0.5254 0.01 7 A. walkeri Elattarchusarchidium 0.6412 0.005 0.6491 0.002 A. walkeri Ophioscion sc iera 0.6412 0.005 0.6491 0.002 A. walkeri Porichthys nau topaedium 0.7166 0.002 0.7255 0.001 A. walkeri Stellife r mancorensis 0.7166 0.002 0.7255 0.00 1 A. walkeri Trinectes sp. 0.4815 0.026 0.4969 0.026 A. walkeri Urotrygon chilensis 0.7166 0.002 0.7255 0.001 BAR TELS et al. : Fishes of the Gulf of Nicoya, Costa Rica 97

KendaU's Tau Spearman's Rho Species Species Coef. Signif. Codo Signif.

Anisostremus dovU Arius steindacltneri 0.5369 0.009 0.6030 0.005 A. dovii Antennarius avalon;s -0.4230 0.044 0.4619 0.040 A. dovii Urorrygon chilensis 0.4458 0.049 A. dovii Cynoscion albus 0.4635 0.025 0.5303 0.016 A. dovii Stellife r mancorensis 0.4458 0.049 A. dovii Cy noscion phoxocephalus 0.6792 0.001 0.7659 0.001 A. dovif Porichthys 1U1Utopaediu m 0.4458 0.049

Antennarius avalonis Cy clopsetta sp. 0.4506 0.028 0.5156 0.020 A. avalonís Cynoscion phoxocephalus -0.4115 0.045 -0.4595 0.042 A. avalonis Pa ralonchunis dumerilii 0.4520 0.041 0.4687 0.037 A. avalonis Syacium ovale 0.4580 0.021 0.5267 0.017 A. avalonís Synodus scituliceps 0.4413 0.022 0.5005 0_025

An'us steindachneri Cy noscion albus 0.4797 0.020 0.5446 0.013 A. steindachneri Cynoscion phoxocephalus 0.7123 0.001 0.8843 0.001 A. steindachneri Stellife r illecebrosus 0.4381 0.042 0.4660 0.038 A. steindachneri Sy mphunis sp. 0.5631 0.004 0.6543 0.002 A. steindachneri Synodu s scituliceps -0.4 355 0.021 -0.5228 0.018 A. steindachneri Trin ectes sp. 0.6105 0.003 0.7212 0.001

Bollmonnio chlamydes Dilpterus peMJvianus 1.000 0.001 1.000 0.001 B. chlamydes Symphunis atramematus 0.4756 0_030 0.4971 0.026 B. stigmatura Sciadeichthys troschelii 1.000 0.001 1.000 0.001

Brotula clarkae Sphoeroides furthii 0.5307 0.018 0.5440 0.013 B. clarkae Peprilu s medius 0.5 307 0.01 8 0.5440 0.013 B. clarkae Paralon chuMJs dumerilii 0.4683 0.036 0.4800 0.032 Citharichthys platophrys Haemulopsis nitidus 1.000 0.001 1.000 0.001 C. platophrys Larimus pacificus 1.000 0.001 1.000 0.001 C. platophrys Neopisthopterus tropicus 1.000 0.001 1.000 0.001 C. platophrys Priodonophus equatorialis 1.000 0.001 1.000 0.001

Cy noscioll o/bus Cynoscion phoxocephalus 0.5432 0.007 0.5774 0.008 C. albus Diapterus aureo/us -0.4466 0.048 C. albus Sy mphunis sp. 0.5986 0.002 0.6647 0.001 C. o/bus Elattarchus archidium 0.4445 0.050 C. a/bus Synodus scituliceps -0.4 365 0.022 -0.5477 0.012 C. albus Ophioscion sciera 0.4445 0.050 C. albus Trillectes sp. 0.6235 0.003 0.6961 0.001

Cy noscion phoxocephalus Sy mphurns sp. 0.5294 0.006 0.6181 0.004 C. phoxocephalus Synodus scituliceps -0.4022 0.031 -0.5016 0.024 C. phoxocephalus Tr inectes sp, 0.4612 0.023 0.5218 0.01 8

Dilpterus aureo/us Sya cium ovale 0.4699 0.037 D, aureolus Tn'nectes sp, -0.4466 0.048

Diapterus peruvianus SymphuMJs atramentatus 0.4756 0.ü30 0.4971 0.026

Diplectrum pacificum SymphuMJs atramentatus 0.45 13 0.022 0.5329 0.016

Elattarchus archidium Ophioscion sciera 1.000 0.001 1.000 0.001

Haemulopsis nitidus Neopisthopterus tropicus 1.000 0.001 1.000 0.001 H. nitidus Larimus pacificus 1.000 0.001 1.000 0.001 H. nitidus Pn'odonophus equatorialis 1.000 0.001 1.000 0.001

Larimus pacificus Neopisthopterus tropicus 1.000 0.001 1.000 0.001 L. pacificus Priodonophus equatorialis 1.000 0.001 1.000 0.001

Lepophidium prorates Symphurnsatramentatus 0.4447 0.049 98 REVIST A DE BIOLOGIA T�OPICAL

Kendall'sTau Spearman's Rho Species Species Coef. Signif. Coef. Signif.

Men ticirrhus nasus Stellife r jitrthii 1.000 0.001 1.000 0.001

Micropogoniasaltipin nis Polydactylus approximans 1.000 0.00 1 1.000 0.001 M. altipinnis Trichiurus nitens 1.000 0.001 1.000 0.001

Neopisthopterus tropicus Priodonophus equatorialis 1.000 0.001 1.000 0.001

Peprilus medius Sphoeroides jitrthii 1.000 0.001 1.000 0.001

Polydactylus approximans Trichiurusnitens 1.000 0.001 1.000 0.001

Porichthys nautopaedium Stellife r mancorensis 1.000 0.001 1.000 0.00 1 P. nautopaedium Uro trygon chilensis 1.000 0.001 1.000 0.001

Stellifer chrysoleu ca Prionotus horrens 1.000 0.001 1.000 0.001

Stellife r mancorensis U. chilensis 1.000 0.001 1.000 0.001

Syacium ovale Cyclopsetta sp. 0.45 27 0.01 8 0.5907 0.006 S. ovale Synodus scituliceps 0.4901 0.007 0.5831 0.007

Symphurusatr amentatus Symphurus sp. -0.4562 0.021 -0.5 287 0.01 7 S. atramentatus Synodus scituliceps 0.3799 0.048

Symphurussp. Trin ectes sp. 0.5442 0.006 0.6066 0.005

Synodus scituliceps Trinectes sp. -0.4365 0.022 -0.5477 0.01 2

TABLE 16

Gulf of Nicoya, Central America: Physical data summary fo r Cruise (February 1979) 1

STATION NUMBIlR

8N 9N 10 ION 11 12 13 14 15 16 17 18

Total Weight 30.8 14.1 14.2 8.4 16.8 28.3 8.5 9.5 3.4 16.8 4.3 8.9 4.4 6.5 12.8 14.5 6.4 14.4 3.9 29.7 (kg)

Total number of species 13 14 11 11 13 16 14 10 15 12 13 12 14 19 23 19 18 13 17

Distance fr om Orean (km) 42 41 37 30 20 20 15 15 15 15 15 15 15 20 30 37 41 43 SO 62

Dissolved Oxygen Leve! 2.8 5.2 5.0 1.6 1.4 2.0 2.0 1.4 4.0 1.8 1.2 1.4 1.4 5.6 3.2 3.8 4.0 4.8 6.2 3.9

Depth (m) 50 SO 30 40 50 45 55 SO 40 48 SS SO 48 30 28 16 25 15

Temperature 23 26 24 25 18 19 18 17 22 18 17 17 17 28 23 25 26 26 27 27 (C)

Salinity ° ( /00) 34 34 34 35 35 35 34 34 35 35 34 35 34 33 35 33 34 34 33 33 BA RTEL S et al. : Fishes of the Gulf of Nicoya. Costa Rica 99

TABLE 17

Gulf of Nicoya, Ce ntral America: Ph ysical data summary fo r Cruise II (Ju ly 1979)

STA TION NUMBER

4 8N 10 ION 11 12 13* 14 15 16 17 18 19* 20 21*

Total Weight 22.6 3.7 9.6 9.7 4.5 14.6 10.3 13.1 6.0 6.9 19.1 22.1 10.4 27.1 1.7 19.4 21.9 9.1 9.1 98.5 9.4 89.8 (kg) Total number ofspecies 22 15 17 24 19 16 20 10 19 21 22 24 27 12 39 27 26 21 22 25 29

Distance from Ocean (km) 42 41 37 30 20 20 15 15 15 15 15 15 20 30 37 41 43 50 62 62 45 53

Dissolved Oxygen Leve1 4.5 5.7 4.6 4.1 2.0 2.7 2.1 2.1 \.b 5.1 3.0 2.8 2.6 6.2 5.2 5.1 5.0 6.2 4.4 5.8 4.8 5.6

Depth (m) 50 20 25 40 60 55 65 60 35 45 47 60 45 28 17 16 20 15 18 18

Temperature 26 27 26 24 16 19 18 14 26 24 14 17 19 27 24 23 24 24 23 24 23 23 (C) Salinity (0/00) 34 33 34 34 36 36 37 37 34 36 37 36 36 33 35 35 34 34 35 33 36 34

• On1y two thirds of fishcounted.

TABLE 18

Gulf of Nicoya, Central America: Physical data summary fo r Cruise II (A pril 1980)

STATION NUMBER

10 11 12 13 14 15 16 17 18 19 20 21

Total Weight (Kg) 50.5 28.4 22.8 14.7 18.8 24.7 11.3 5.1 27.3 14.1 6.2 29.5 5.4 31.0 67.3 84.1 41.2 84.3 70.2 93.9

Total number 12 10 26 20 20 24 16 20 27 23 19 ¡5 17 17 of species 33 26 27 25 31 27

Distance [rom 42 37 30 20 20 15 15 15 15 20 30 37 41 43 50 62 62 45 53 Ocean (km) H

Dissolved Oxygen Leve! Not available

50 50 30 40 50 45 55 40 55 48 30 28 16 Depth (m) 25 7.5 15 18 18

Temperature 22 21 21 21 17.5 20 18 18 18 17 18 21 28 27 27 28 27 28 27 25 (e) Salinity (0/00) 32 33 33 32 33 32 33 33 30 30 31 29 28 39 30 31 28 28 32 32

Diversity remained relatively constant 1 nf ormation presented in this report over the study periodo Shannon-Wiener (H') should be used as a starting point for more index values ranged from 0.671 to 3.163 in-depth life history studies of the for zones and between 3.186 and 3.622 for imp ortant commercial and ecological species the cruises. High species richness accounted common to the Gulf of Nicoya. These for the relatively high H' compared to studies, along with careful monitoring of temperate estuarine are as. water quality, would assist scientists and 100 REVIST A DE BIOLOGIA TROPICAL managers in making proper fisheries El Golfo de Nicoya puede dividirse en tres management and water resource decisions in zonas con base en parámetros físicos considera­ the fu ture. dos en cada sitio de recolección (temperatura del agua, oxígeno disuelto, salinidad, profundi­ ACKNOWLEDGMENTS dad y distancia desde la boca del Golfo). Se de­ terminó pocos cambios en la posición de estas Tbis study was supported by funds from zonas durante el lapso de este estudio , lo que the Sea Grant International Cooperative indica una configuración estuarina relativamen­ Assistance Program, the University of Cos ta te estable desde el punto de vista biológico, ba­ Rica, and the Organization for American jo condiciones de estaciones seca y lluviosa. No States, and represents portions of a thesis se observó cambios significativos estacionales subrnitted to the fa cult y of the School of con respecto al número, biomasa, porcentaje de G ra duate Studies of the University of especies ni en la separación por grupos con base Delaware in partial fulfillrnent of the en la talla. requirements for the degree of Master of Se observó dos tipos principales de patrones Science in Marine Studies. Thanks are due de distribución de los peces. Varias especies pre­ Dr. F ranklin C. Daiber, Dr. Charles E. sentan una distribución muy amplia y éstas se Epifanio and Dr. Vic Lotrich of the encontraron en todas las estaciones. Otras espe­ University of Delaware who provided critical cies presentaron una distribución restringida, evaluations of a prelirninary draft of this ya sea a la parte superior o inferior del Golfo. paper and to John R. Casedevall who En la parte superior los grupos dominantes provided advice and assistance in statistical son los sciánidos, bagres (Ariidae) y los lengua­ analysis of the data. Measurements were dos (Soleidae, Cynoglossidae y Syacium ovale). taken from the University of Delaware's Estos peces muestran preferencia por las aguas R/V Skimmer and we are grateful to más tibias, someras y de menor salinidad de la Donald Evans, Rolando Hoffmeister, parte superior del Golfo. Los lenguados (Bothi­ Tirnothy Pfeiffer, and Thomas White who dae), gobios (Bollmannia spp.), morenas y cón­ served as officers and crew of the vessel. gridos (Hildebrandia nitens, Priodonophus Additionally we thank the students from equatorialis y Muraenesox coniceps) y varias the University of Costa Rica and the otras especies dominan en aguas más frías y de University of Delaware who assisted in mayor salinidad de la parte inferior del Golfo. collection and analysis of data. We extend special thanks to Dr. Manuel M. Murillo who coordinated relations between the two universities. LITERATURE CITED

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