Programa de Pós-Graduação em Zoologia - PPGZOOL/ICB
URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2343
O Programa de Pós-Graduação em Zoologia (PPGZOOL) do Instituto de Ciências Biológicas (ICB) foi consolidado como um convênio entre Universidade Federal do Pará (UFPA) e Museu Paraense Emílio Goeldi (MPEG).
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Item Acesso aberto (Open Access) Alimentação, distribuição espacial e sazonal das espécies de Arius (Siluriformes : Ariidae) do Estuário amazônico(Universidade Federal do Pará, 1999-08-30) MENDES, Fabrício Lemos de Siqueira; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326The Family Ariidae (Order Siluriformes) contains marine and estuarine catfishes distributed along the coasts of ali the continents, inhabiting tropical and subtropical shores where they live in shallow waters with sandy or muddy bottoms. In the Amazon River estuary in Pará State, Brazil, there are seven species belonging to the genus Anus (A. couma, A. parkeri, A. rugispinis, A. quadriscutis, A. grandicassis, A. phrygiatus e A. proops). The aim of this study is to identify feeding preference, feeding overlap, spatial distribution and seasonal distribution of the species of genus Anus (Siluriformes, Ariidae) of the Annazon stuary. Collections were made from August to October 1996, and February to April and August to October 1997. Specimens were captured with bottom nets without escape doors belonging to the piramutaba fishing fleet of the Amazon estuary. There are two species groups in the genus Anus: those that feed on crustaceans (A. rugispinis, A. quadriscutis, A. grandicassis, A. phtygiatus e A. proops), and those that feed on fish (A. couma, A. parken). In relation to feeding overlap, ali the species demonstrated a certain degree of feeding overlap, as well as spatial overlap. A. couma and A. phrygiatus. are the most abundant in the 5-10 m depth range and A. rugispinis, A. quadriscutis, A grandicassis and A. parkeri e A. proops in the 10-20 m range. A. phrygiatus is the only species that has a greater abundance during the rainy season, and the other species are present both in the dry as well as the rainy season.Item Acesso aberto (Open Access) Determinação da idade e crescimento da piramutaba Brachyplatystoma vaillantii (Valenciennes, 1840) (Siluriformes : Pimelodidae) capturada no Estuário amazônico(Universidade Federal do Pará, 2001-05-31) PIRKER, Lilianne Esther Mergulhão; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326The specimens of piramutaba (Brachyplatystoma vaillantii) analyzed in this research were obtained from experimental fisheries in the amazon estuary. For the study of age determination pectorals and dorsal spines, opercules, otoliths (lapillus) and vertebrae were analyzed. From the analysis of these structures it was concluded that the vertebrae is the most appropriate bony structure for the age determination of piramutaba. This is so because the vertebrae showed good resolution in annulus (59%), and it also has a significant exponential relationship (r² = 0,9889 and P<0,05) between the radius of the vertebrae and the fork length of fish. The seasonal rings were validated using length frequency analysis. Two annual rings are formed on the vertebrae of piramutaba. The weight-length relationship seen in piramutaba describes its growth as allometric and the equation that describes its growth is: Wt = 6,1 * 10-6 * Lf3,1129. The sexual proportion of piramutaba observed was not 1:1, as the number of females was superior to the males. On vertebraes of piramutaba a maximum of ten rings were observed. The von Bertalanffy growth model was utilized in this research to estimate the length and weight equations. The growth parameters (k, t0 e L∞) were estimated through four different methods: rings reading, backcalculation, rings modal progression and length frequency analysis. The growth parameters were k = 0,138 ano-1, t0 = -0,239 e L∞ = 110,5 cm (tings xeaffing); k = 0,119 ano-1, t0 = -0,202 e L∞ = 110,5 cm (backcakulation); k = 0,096 ano-1, t0 = -0,146 e L∞ = 110,5 cm (rings modal progression) and k = 0,127 ano-1, t0 = -0,236 e L∞ = 110,5 cm (length frequency analys is).Item Acesso aberto (Open Access) Diversidade, distribuição e estrutura da comunidade de peixes na Estação Científica Ferreira Pena: Amazônia Oriental(Universidade Federal do Pará, 2001-11-20) MONTAG, Luciano Fogaça de Assis; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326The conservation of the biodiversity in aquatic ecosystems is one of the most important and difficult challenges in the current world. According to available information, the biodiversity of aquatic ecosystems is poorly understood in comparison with tropical terrestrial ecosystems. Thus, systematic and taxonomic analyses, the understanding of phylogenetic, biogeographical and ecological relationships represent items that need to be investigated. The first question addressed is the characterization of the ecosystem. We observed that the environmental features, mainly wideness and depth, ranges spatially along the rivers and possess the inferior zone with strong characteristics of river—lake transitional areas. The following question was to estimates fishes richness of in the Ferreira Penna Scientific Station. In order to answer this question, we used protocol techniques and obtained 130 species, of these 39 were separated by morphospecies. This fact indicates that approximately 30% of the fauna might be new or there is no available bibliography for identification. The species collected in the inventory are considered to represent a reasonable set of the ichythyofauna of the region. Lastly, we aimed to characterize fish communities and expose the patterns of distribution of species concerning the investigated habitats. As a result, we observed that the com position of species in the communities followed the substitution and addition pattern. The greatest diversity of species was observed for the final zones of the rivers. The increase in the water volume and area in some habitats of the rivers makes possible their exploitation by a larger number of individuals or new species.Item Acesso aberto (Open Access) Ecologia de lagos da planície inundada do baixo Tapajós: diversidade, estrutura de comunidade de peixes e percepções socieconômicas dos moradores de Alter do Chão, Santarém-PA(Universidade Federal do Pará, 2005-10-07) COSTA, Luiz Rodolfo Ferreira da; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326Item Acesso aberto (Open Access) História natural das raias de água doce (Chondrichthyes: Potamotrygonidae) na Ilha de Marajó (Pará- Brasil)(Universidade Federal do Pará, 2008) ALMEIDA, Mauricio Pinto de; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326The present study was on the natural history of freshwater stingrays species (Potamotrygonidae) of the Marajó Island. It was carried out in four sampling points (Afuá, Lago Arari, Muaná and Soure) in dry, rainy and transition seasons, in 2005 throughout 2007. Five species were captured in this area, Plesiotrygon iwamae, Paratrygon aiereba, Potamotrygon motoro, Potamotrygon orbignyi and Potamotrygon scobina and two other new species, presently in description. Data on the Potamotrygonidae family composition and distribution were obtained, such as frequency of occurrence, biomass and fishery gear selectivity. Data on the reproduction and feeding of the species were described for this region, with emphasis on Potamotrygon motoro.Item Acesso aberto (Open Access) Morfometria e descrição de otólitos de dourada (Brachyplatystoma rosseauxii) (Castelnau, 1855) e de piramutaba (B. vaillantii) (Valenciennes, 1840) (Siluriformes: pimelodidae) e verificação de anéis de crescimento em otólitos de juvenis de dourada e de piramutaba na Ilha de Colares - Baía de Marajó-PA(Universidade Federal do Pará, 2008-10-09) PIRKER, Lilianne Esther Mergulhão; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326The dourada (Brachyplatystoma rousseauxii) and the piramutaba (B. vaillantii), two migratory freshwater catfishes, are exploited by both traditional and industrial fishery in the Amazonian. They are very important for the commercial fishery in this region and their stocks are currently sobrexploted. However there is a lack of information concerning the biology and ecology of juvenile stages of these catfishes in the scientific literature. In population dynamics studies, the correct age estimate influences the growth parameters, which are important to evaluate stocks. The studies of age determination are usually made using sub-adults and adults specimens. The juveniles are not analyzed and their age is back-calculated. Which could result in an error estimate. The aims of the present research were: (1) to describe and estimate the relation between the lapilli otoliths morfometric measurements and the body measurements of dourada and piramutaba, and (2) to examine the occurrence of the first growth rings in the juvenile specimens. The morfometric and descriptive studies were carried out using otoliths from dourada and piramutaba juveniles, sub-adults and adults collected in the municipalities of Colares (PA), Almeirim (PA), Santarém (PA), and Manaus (AM), in the District of Mosqueiro (PA), and in the Amazon estuary. The period of collection was different for each local, to September of 1996 to January of 2006. The following relations were estimated: furcal length from specimens (LF) x total weight from specimens (WT); LF x maximum otolith length (MOL); LF x maximum otolith width (MOW); LF x otolith total weight (OWT); WT x MOL; WT x MOW and WT x OWT. The estimated equations were: Dourada: WT = 9.5 x 10-6 x LF 3.0279, LF = 25.259 * MOL1.1571, LF = 40.626 * MOW1.2127, LF = 840.419 * OWT0.4077, WT = 0.125 * MOL3.6547, WT = 0.568 * MOW3.8294, WT = 7549.98 * OWT1.2651; Piramutaba: WT = xxx 5.4 x 10-6 x LF 3.1441, LF = 31.871 * MOL1.3381, LF = 55.852 * MOW1.3722, LF = 1641.064 * OWT0.4686, WT = 0.3127 * MOL4.1857, WT = 1.823 * MOW4.2788, WT = 66675.977 * OWT1.4508. In the descriptive study, the lapilli of dourada and piramutaba were classified in the following categories according to their development and specimens LF: dourada I (60 a 80 mm), dourada II (80 a 110 mm), dourada III (110 a 210 mm), piramutaba I (65 a 80 mm), piramutaba II (80 a 110 mm), and piramutaba III (110 a 190 mm). In the lapillus ring reading study, only the juveniles specimens £ 200 mm LF were used. In the Marajó bay, douradas and piramutabas with 175.03 mm and 171.03 mm mean LF, respectively, showed the first growth ring. Both species were between nine and twelve months old when they showed the first growth ring. The mean rays of the first hyaline ring in the transversal cut of dourada’s and piramutaba’s lapillus were 0.36 mm (± 0.03) and 0.33 mm (± 0.01), respectively. The mean total ray of the lapillus transversal cut was 0.64 mm (± 0.14) in dourada and 0.53 mm (± 0.09) in piramutaba. The estimated equation relating the total ray of the lapillus transversal cut of douradas juveniles with its LF was LF = 248.589 * Rt1.1901. The estimated equation for piramutaba was LF = 400.494 * Rt1.7178. Douradas and piramutabas 60-70 mm LF were three to six months old, 70-110 mm LF were six to nine months old, and 110-200 mm LF were nine to twelve months old.Item Acesso aberto (Open Access) Ocorrência, biologia e uso das raias de água doce na Baía de Marajó (Pará, Brasil), com ênfase na biologia de Plesiotrygon iwamae (Chondrichthyes : Potamotrygonidae)(Universidade Federal do Pará, 2001-06-29) CHARVET-ALMEIDA, Patricia; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326The present study included stingrays of the Potamotrygonidae family, the only one among elasmobranches that possesses ali representatives exclusively in freshwater. It was carried out in the Islands of Cotijuba and Colares, which are located in the estuarine region of the Marajó Bay, during the rnonths of May, August, October and December of 2000. The sampling included the genera Plesiotrygon, Potamottygon, Paratrygon and a fourth genus that is currently being described. Information related to the frequency of occurrence and biomass indicated the predominance of Potamottygon spp. and Plesiotrygon iwamae in this region. The fishery equipment used selected the size of the stingrays captured. Specific observations were made concerning the feeding and reproductive biology of the species P. iwamae. Stomach content analysis, using the index of relative importance (TRT), indicated that this species feeds mainly on crustaceans and fish. Macroscopic observations of the reproductive organs of males and females were made. The results indicated that this species presents aplacental matrotrophic viviparity with trophonemata. Probably its reproductive cycle is seasonal, is related to salinity changes and several females are captured as they approach the beaches of this bay to reproduce. In this region the freshwater stingrays are routinely captured mainly for food, medicinal and ornamental purposes_ A high number of stingray accidents and treatments were observed in both islands. The conservation of the species of freshwater stingrays requires more knowledge about their biology, follow-ups on their exploration and perhaps management measures.Item Acesso aberto (Open Access) A pesca comercial dos tucunarés Cichla Spp. (Peciformes, Cichlidae) no Reservatório da UHE-Tucuruí, Rio Tocantins, PA(Universidade Federal do Pará, 2007) BOTELHO, Marília Cunha; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326This study describes the freshwater fishery based on peacock bass ("tucunaré") Cichla spp. in the lower Tocantins River, Pará state, northern Brazil, in the area influenced by the Tucuruí hydroelectric dam, with emphasis on the reservoir. The study was divided in two parts: Chapter I describes the commercial peacock bass fishery with relation to fishing gear, fishing strategies, utilized environments, seasonality, and local fishing management according to the fishermen’s perception. The fishermen’s local knowledge was studies, including their ethnobiological classification of peacock bass types, and the social, ecological, and economical aspects involved. Interviews with fishermen and participation observation were conducted in situ. The Tucurui reservoir peacock bass fishery is of great importance in the social and economic life of these fishermen and is their main income source. This fishery occurs in specific places in the lake and uses rudimentary methods and equipment. According to the fisherman, production is influenced by environmental variables and by the use of guild nets, that the fishermen say drives away peacock bass from the fishing environments. The use of environments for fishing is the main source of conflict among fisherman. Social relations among fishermen in a system of partnership and the presence of middlemen diminish the the fisherman’s income. Fishermen possess consistent knowledge on the ecology and behavior of peacock bass. Their system of fish classification recognizes three ethnospecies, two of which constitute a single scientific species. Chapter II treats peacock bass yields at landing points in the lake, from 1997 to 2003, according to data furnished by ELETRONORTE, and a measure of fishing effort was considered that was most adequate for these data. The data were analyzed according to port, fishing gear, type of boat, fishing grounds, and river flood cycle. The data demonstrated that different cities possess fishing fleets with their own characteristics and that these utilize nearby fishing grounds. The greatest yields were during periods of flooding and subsidence of water levels, with hook and line fishery being responsible for most of the catch. Canoes were the most used boats. The yield data at landing points indicate that this fishery is more important in cities and areas located on the lake. Fish yield for unit of effort only shows adequate statistical behavior when analyzed for fishing grounds and the adjusted units of effort are number of fisherman per days of fishing, after logarithmic transformation.Item Acesso aberto (Open Access) A pesca do tamoatá Haplosternum litorale (Hancock, 1828) (Siluriformes : Callichthyidae), na ilha de Marajó-Foz Amazônica(Universidade Federal do Pará, 2005) ALBUQUERQUE, Adna Almeida de; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326Hoplosternum littorale (Hancock, 1828) (Siluriformes, Callichthyidae) is a small catfish known in Brazilian Amazon as tamoatá. It is the main fisheries resources in the swamps and floodplain of the Marajó Island, especially in the Arari Lake and Arari River, near the Santa Cruz do Arari city. The inland Marajó fishery is described based in the field observation and local fishermen interview. The seine and gillnet are the most important fishing gears used by the fishermen with the canoe with paddle. The fish is stocked in boats with ice box called as geleiras. The managers of those boats buy the fish caught by the local fishermen. The boats wait some days to complete the ice box of fish and then transport the fish to be sold in the urban centers. The tamoatá caught in the Marajó Island between 1993 and 2004 and yielded in the Ver-O-Peso fish port was related with the total days spent by the geleiras in the Marajó by month and with the monthly rainfall measured in the meteorological station of the Soure city. The dry season is the most productive period, when the fish are concentrated in the remains water pools in the lake and river. The analysis of covariance (ANCOVA) indicates a significant relationship between the monthly tamoatá yield and days and rainfall factors. The relationship is positive to the days and negative to the rainfall. However, the relationship between the annual tamoatá yield and the rainfall is significant and positive. The lower amount of rainfall measured in the last years may explain the recent low caught of tamoatá in Marajó Island.Item Acesso aberto (Open Access) Pesca, alimentação e ecologia reprodutiva e embrionária de carataí (Pseudauchenipterus nodosus) (Siluriformes, Auchenipteridae) no rio Marapanim, Marapanim, Pará(Universidade Federal do Pará, 2000-10) ASSUNÇÃO, Maria Ivaneide da Silva; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326This study presents information on the fisheries, diet, reproduction and embryonic development of carataí fish, Pseudauchenipterus nodosus (Siluriformes, Auchenipteridae), based on data collected between December 1998 and April 1999 in Marapanim River, Pará State, Brazil. Daily and biweekly samplings were collected by means of weirs and pound nets at four sites along the river: the bay, the estuarine funnel, mid-river and the upper portion. It was confirmed that fishing took place during the reproductive period of the species, and that its features varied according to the different sites. Most of the fishermen’s yield was sold in neighboring districts. Catch data along the river pointed the upper portion (33%) and mid-river (44%) as the most productive sites and indicated that carataí performs a biweekly ascending movement. The species ingested larger amounts of food in turbid waters, mainly in tide streams: its diet included annelids, arthropods, mollusks and fishes. Local observations and frequency distributions of ovaries at mature, reproductive and spent stages respectively indicated that carataí spawns in places with fresh and clean waters, on river and creek shores, under a canopy of undisturbed forests. Spawning occurred during the last peaks of the highest waters of spring tides, and following their retraction the eggs were incubated in the soil for about 11 days until the coming syzygy, under temperatures of 22 to 27.5 °C. After hatching, the embryos either remained enclosed within the egg shell until flooded by the tide, or got out of the shell and onto the ground, where they could survive for a couple of hours. Those latter embryos had the ability of taking up exogenous food as they hatched, while those incubated in water would tend to hatch prematurely and show little perception of the surrounding environment. Intervention in the annual recruitment of carataí in Marapanim River seemed to be more dependent on local rain distribution and on the integrity of the forest than on fishing activities.Item Acesso aberto (Open Access) Pesca, alimentação, reprodução e crescimento do Amuré, Gobioides broussonnetii Lacepède, 1800 (Pisces : Gobiidae) no Estuário Amazônico, município de Vigia - Pará(Universidade Federal do Pará, 2005-03) BRAGANÇA, Alexandre José Machado; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326Gobioides broussonnetii, the largest species of the family Gobiidae, is found in the western Atlantic Ocean, from the United States to Rio Grande do Sul, Brazil. It is abundant in the Amazon River estuary where it is typically found in the brackish waters of mangroves. Besides being an important link in the Amazon estuary food web, this species is a resource exploited by local fishermen. Fishing practices, diet, reproduction, and growth of Gobioídes broussonnetii were studied in Marajó Bay, municipality of Vigia, Pará state, Brasil, between September of 2003 and August of 2004. Specimens were obtained from local fishermen and information about fishing practices for this species were obtained through field-observation and from interviews with fishermen. The diet was studies by means of based on 314 specimens. Reproductive aspects included the period of reproduction and the size at first maturation of 749 specimens. Growth parameters were estimated using the indirect method based on the total lengths of 1155 specimens. Gobioides broussonnetii, known locally as "amure" in the Amazon River estuary, is captured on the muddy bottom in shallow water and is used as bait in commercial fishing. In general, the species is phytophagous, and stomach contents analyses showed the algae Coscinodiscus concinus to be most abundant food item Larger amount of food in the stomachs were recorded during the dry season (July to December). The reproductive period for G. broussonnetii in the study area ranged from January to June_ The mean length of the first gonadal maturation was 23,9 cm. The observed sex ratio was 1:1 (X²= 0,834, P<0,001). Results obtained in this study indicate that G. broussonnetii uses the Amazon estuary as an spawning, nursery, and feeding area. Macroscopic examination of the gonads indicated that the reproductive season tanges from January to June, although there is a single spawning per year, from February to April. Nine age groups of G. broussonnetll were found in the Amazon estuary. Estimates for growth parameters were obtained as follows: L∞ = 67,36 ( K=0,205 ano-1, Ø = 3,014). The length-weight relation was significantly different between males and females, with females heavier than males.Item Acesso aberto (Open Access) Pesca, policromatismo e aspectos sistemáticos de Potamotrygon scobina Garmam, 1913 (Chondrichthyes : Potamotrygonidae) da região da Ilha de Colares - Baía de Marajó - Pará(Universidade Federal do Pará, 2003-03-07) ALMEIDA, Mauricio Pinto de; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326The present study included specimens of the Family Potamotrygonidae, the only one among elasmobranchs formed entirely by freshwater representatives. This research was developed in the estuarine region of the Marajó Bay, in the island of Colares, during the months of May, August, October and December of 2000, December of 2001 and March of 2002. Sampling included the genera Plesiotrygon, Potamottygon, Paratrygon and a fourth undescribed genus, totalizing 723 captured specimens. Frequency of occurrence and biomass results indicated a predominance of the genus Potamotrygon especially of the species P. scobina in this area. Fishing gear utilized influenced the size of the stingrays captured. Specific observations related to the dorsal color patterns, size and sexual distribution of the species P. scobina were made. Results of multivariate statistical analysis and molecular genetics indicated that dorsal color patterns as currently employed in distinguishling morphotypes in fact did not indicate separate species and a single group was formed. Three previously undescribed dorsal color patterns for sub-adults / adults and two new patterns for juvenile specimens were identified for P. scobina. External characters analyzed for this species presented a wide variation in form, number, size and structure disposition that were more evident in sub-adults / adults. In this region, freshwater stingrays are routinely captured mainly for food and for medical and ornamental purposes. The conservation of freshwater stingrays species requires further knowledge about their biology and taxonomy in order to follow-up its exploitation and perhaps indicate management procedures.Item Acesso aberto (Open Access) Variação sazonal e espacial da estrutura de comunidades dos peixes demersais da Região de Foz dos Rios Amazonas e Tocantins - PA (0º 10'S - 2º30'N; 47º50'W - 50º30'W) - Brasil(Universidade Federal do Pará, 1999-11-23) TORRES, Marcelo Ferreira; BARTHEM, Ronaldo Borges; http://lattes.cnpq.br/4192105831997326The composition, abundance and frequency of the demersal fish fauna from the Amazon estuary were studied in three areas which ones were defined as circumscribed within the isobath ranges of 5-10 m, 10-20 m and 20-50 m. The main objectives of this work were to compare the diversity, abundance and distribution of demersal fish fauna in these three areas during one hydrological cycle, and evaluate the infiuence of environmental variables on the community structure. Samples were taken on board of two piramutaba fishing vessels, using a bottom trawl net, for a given seasonal survey of six 15-day trips in the dry season (March and Apri1/97) and in the rainy season (August and September/97). A number of 91 species were caught in a total of 237 samples and Sciaenidae and Ariidae were the most diverse families, represented by 25% of total species. The Ariidae' species which ocurred in the area were very abundant. The most abundant species were Macrodon ancylodon (Sciaenidae) (56,2%) and Brachyplatystoma vaillantii (Pimelodidae) (13,6%) in the rainy season, and Macrodon ancylodon (31%) and Stellifer rastrifer (15,8%) (Sciaenidae) in the dry season. In area 1 Brachyplatystoma vaillantli (Pimelodidae) and Macrodon ancylodon (Sciaenidae) were the most abundant species in both periods, and the same occurred for Macrodon ancylodon and Stellifèr rastrifer (Sciaenidae) in area 2, and for Macrodon ancylodon (Sciaenidae) and Bagre bagre (Ariidae) in area 3. The most frequent species sampled were Macrodon ancylodon (Sciaenidae) (40,9%) and Anchoa spinifer (Engraulididae) (35%) in the rainy season, and Macrodon ancylodon (Sciaenidae) (45,6%) and Anus grandicassis (Ariidae) (38,4%) in the dry season. In area 1 Brachyplatystoma vaillantii and Brachyplatystoma flavicans (Pimelodidae) were the most frequent species, considering each period; the same was observed for Macrodon ancylodon (Sciaenidae) and Bagre bagre (Ariidae) in area 2, and Macrodon ancylodon (Sciaenidae) and Anchoa spinifér (Engraulididae), in area 3. The dominant species were: Macrodon ancylodon (Sciaenidae) in the rainy season (56% of the specimens collected); and Macrodon ancylodon, Stellifér rastrifer (Sciaenidae) and Anus quadriscutis (Ariidae) in dry season, which represented 61% of fishes caught. In area 1, Brachypiatystoma vaillantii (Pimelodidae) and Macrodon ancylodon (Sciaenidae), were dominant (73%) in the rainy season, and both of them together with Anus grandicassis (Ariidae) were dominant (53%) in the dry season. area 2 only Adacrodon ancylodon (Sciaenidae) was dominant (64%) in the rainy season, and Macrodon ancylodon and Stellifer rastrifèr (Sciaenidae) were dominant (53%) in the dry season. In area 3, just one species Macrodon ancylodon (Sciaenidae) was considered dominant (70% in the rainy season and 49% in the dry season). Distribution patterns were influenced by salinity. Area 1 presented the greatest diversity and evenness as compared with the others. Area 2 presented the greatest richness, and area 3 presented the highest dominance. Three communities were identified: one characterized by species from continental waters that explore shallow areas at depths of less than 20 m; another one formed by salinity resistant species, distributed through a wide range from the estuary, mostly in the area circumscribed within the isobath range of 10-20 m; and a third one with marine species distributed in areas at depths of 10 m to 50 m.