Genidens Barbus Research Articles

First record of partial albinism in two catfish species of Genidens (Siluriformes: Ariidae) in an estuary of Southern Brazil

This study reports the first occurrence of partial albinism in two species of Ariidae: Genidens barbus and Genidens planifrons from an estuary of Southern Brazil. Possible causes of the simultaneous occurrence of three specimens with partial albinism are discussed, including random genetic alterations, chronic contamination effects and small effective population size, which may favor the expression of the recessive albino gene.

Ion levels in the gastrointestinal tract content of freshwater and marine–estuarine teleosts

This study investigated the relationship between ion levels (Na⁺, Cl⁻, K⁺, Ca²⁺, and Mg²⁺) in the fluid phase and total chyme of the contents of the gastrointestinal tract segments of freshwater and marine-estuarine teleosts collected in different salinities (0-34 ppt) in estuarine and freshwater portions of the São Gonçalo channel, southern Brazil. In addition, the relative contribution of feeding and osmoregulation to the ionic content of each portion of the gastrointestinal tract of fishes collected in different ambient salinities was analyzed. There was no relationship between salinity and ion levels in the fluid phase and total chyme of the segments of the gastrointestinal tract when considering all species together. However, there was a significant positive relationship between salinity and ion levels in the fluid phase and total chyme of two fish species (Micropogonias furnieri and Genidens barbus) collected in three or more different salinities. In most species, ion levels in the fluid phase and total chyme changed throughout the gastrointestinal tract, suggesting absorption, but the ionoregulatory mechanisms of the gastrointestinal tract seem to vary according to species.

Plasma ion levels of freshwater and marine/estuarine teleosts from Southern Brazil

The purpose of this study was to investigate Na+, Cl-, K+, Ca2+, and Mg2+ levels in the plasma of freshwater and marine/estuarine teleosts collected at different salinities (0 to 34) from the estuarine and freshwater portions of the São Gonçalo channel in Southern Brazil. Any relationship between plasma ion levels and salinity and the capacity of ionic regulation of teleosts found at three or more different salinities (Genidens barbus and Micropogonias furnieri) was also investigated. Results showed no relationship between plasma ion levels and salinity when considering all species together, but the two species collected from three or more different salinities showed a significant positive relationship between plasma ion levels and salinity, indicating that G. barbus and M. furnieri have a high capacity to regulate plasma ion levels at both low and high salinities.

Cytogenetic analysis of three sea catfish species (Teleostei, Siluriformes, Ariidae) with the first report of Ag-NOR in this fish family

Despite their ecological and economical importance, fishes of the family Ariidae are still genetically and cytogenetically poorly studied. Among the 133 known species of ariids, only eight have been karyotyped. Cytogenetic analyses performed on Genidens barbus and Sciades herzbergii revealed that both species have 2n = 56 chromosomes and Cathorops aff. mapale has 2n = 52 chromosomes: Genidens barbus has 10 Metacentrics (M), 14 Submetacentrics (SM), 26 Subtelocentrics (ST), and 6 Acrocentrics (A), Sciades herzbergii has 14M, 20SM, 18ST and 4A, whereas Cathorops aff. mapale has 14M, 20SM, and 18ST. The nucleolus organizer regions (NORs) were found in a single chromosome pair on the short arm of a large-sized ST pair in Genidens barbus and on the short arm of a middle-size SM pair in Cathorops aff. mapale. Multiple NORs on the short arms of two large-sized ST pairs were found in Sciades herzbergii. The occurrence of diploid numbers ranging from 2n = 52 through 56 chromosomes and the presence of different karyotypic compositions, besides the number and position of NORs suggest that several numeric and structural chromosome rearrangements were fixed during the evolutionary history of this fish family.

Ontogenetic niche feeding partitioning in juvenile of white sea catfishGenidens barbusin estuarine environments, southern Brazil

Ontogenetic diet changes (prey species richness and size) in juveniles of white sea catfish(Genidens barbus)were tested in three southern Brazilian estuaries: Mampituba (29°12′S), Tramandaí (30°02′S), Chuí (33°44′S). Cluster analysis revealed that white sea catfish juvenile populations in the three estuaries are composed of two feeding groups. These two feeding groups are coincident with a bimodal size–age distribution of the juveniles of white sea catfish. In small catfish (5 to 10 cm TL) copepods were the most numerous prey (Chuí = 86.66%N, Tramandaí = 85.52%N and Mampituba = 52.34%N). In large catfish (10 to 20 cm TL) the most abundant and frequent prey was fish (Chuí: 73.19%N and 74.56%FO; Tramandaí: 85.92%N and 73.33%FO; Mampituba: 52.34%N and 61.54%FO). The Morisita overlap index among small and large fish was low in all estuaries; high values of Morisita's similarity index were observed among same size catfish groups. In all cases, no differences were observed among prey bio-volume curves of same size predator groups (small, F = 0.41,P = 0.65; large, F = 2.19,P = 0.11). In all estuaries, prey size increased significantly with increasing predator size. The 90th regression quantile estimated with most precision the predator–prey size relationship.

Similarity Between Metazoan Parasite Communities of Two Sympatric Brackish Fish Species From Brazil

Between March 2000 and February 2003, 63 specimens of Genidens barbus and 69 specimens of Aspistor luniscutis (Siluriformes: Ariidae), sympatric species from the coastal zone of Angra dos Reis (23 degrees 01'S, 44 degrees 19'W), RJ, Brazil, were necropsied to study their metazoan parasite communities. Parasite community descriptors were calculated and possible similarities statistically tested. Twenty-two species of metazoan parasites were identified, 15 species from G. barbus and 16 associated with A. luniscutis. Nine species were common to both host species; 4 of them exhibited significant differences in terms of abundance and prevalence. Mean total abundance, species richness, diversity, evenness, and Berger-Parker dominance values were not significantly different in the 2 species of fish. Similarity within parasite infracommunities showed highest homogeneity in A. luniscutis. The parasite infracommunities of A. luniscutis and G. barbus were characterized by ectoparasite dominance and scarcity of species with high prevalence. Nevertheless, low values of similarity were observed between infracommunities, and evidence for 2 distinct infracommunities groups was found.

New species of Chauhanellus (Monogenoidea, Platyhelminthes) from the gills of Southern Atlantic marine catfishes (Siluriformes, Ariidae) of the Neotropical region

Two new species of Chauhanellus Bychowsky & Nagibina, 1969 (Dactylogyridae: Ancyrocephalinae) are described from the gills of marine catfishes from the Southwestern Atlantic: Chauhanellus neotropicalis n. sp. from Aspistor luniscutis (Valenciennes, 1840), and Chauhanellus boegeri n. sp. from Genidens barbus (Lacepède, 1803) and Genidens genidens (Cuvier, 1829). This is the first report of species of Chauhanellus in the Atlantic waters and the Neotropical region.

Metal speciation of metallothionein in white sea catfish, Netuma barba, and pearl cichlid, Geophagus brasiliensis, by orthogonal liquid chromatography coupled to ICP-MS detection

Metal speciation analysis in MTs was carried out in two tropical fish species of Brazil, the freshwater fish pearl cichlid ( Geophagus brasiliensis) and the marine fish white sea catfish ( Netuma barba), that are presently used to monitor the effects of heavy metal pollution in aquatic ecosystems in Brazil. In order to obtain the MT fraction, liver cytosols from both fish species where subjected to size exclusion fractionation, monitoring on-line the metal signal (Cd, Cu and Zn) by ICP-MS while protein elution was followed by on-line UV detection. That MT fraction was then separated by anion-exchange (AE)-FPLC, whose optimal chromatographic conditions were optimized for the separation of the different hepatic MT isoforms existing in both fish species. Specific detection of separated metalloforms was carried out again by the hyphenation of the AE chromatographic system with the ICP-MS instrument. The analytical results showed that MTs of these fish species, unknown so far, exhibited unique characteristics in comparison with standard MTs and other fish liver MTs. In fact, MT isoforms of N. barba turned out to be very anionic, as indicated by their high retention in the Mono Q column and the strong ionic strength required to separate them. As for G. brasiliensis, cadmium was exclusively present in only one of the peaks of the MT isoforms showing a unique metal-binding behavior for MT in this fish species. The differences between the MTs among these species and the different association of metals in particular MT isoforms display the importance of the metal speciation analysis in these proteins prior to its use as bioindicators.

Changes in growth seasonality throughout Netuma barba (Lacépède, 1803) (Siluriformes, Ariidae) Ontogeny

Departamento de Oceanografia, Fundacao Universidade Federal do Rio Grande, FURG,C.P. 474, CEP 96201-900, Rio Grande, RS, BrazilCorrespondence to: Gonzalo Velasco, Departamento de Oceanografia, Fundacao Universidade Federal do RioGrande, FURG, C.P. 474, CEP 96201-900, Rio Grande, RS, Brazil, e-mail: pgobgvc@furg.brReceived June 16, 2003 – Accepted January 19, 2004 – Distributed November 30, 2004(With 1 figure)

Community ecology of the metazoan parasites of white sea catfish, Netuma barba (Osteichthyes: Ariidae), from the coastal zone of the state of Rio De Janeiro, Brazil.

Between March 2000 and April 2001, 63 specimens of N. barba from Angra dos Reis, coastal zone of the State of Rio de Janeiro (23 degrees 0' S, 44 degrees 19' W), Brazil, were necropsied to study their infracommunities of metazoan parasites. Fifteen species of metazoan parasites were collected: 2 digeneans, 1 monogenean, 2 cestodes, 1 acantocephalan, 2 nematodes, 6 copepods, and 1 hirudinean. Ninety-six percent of the catfishes were parasitized by at least one metazoan parasite species. A total of 646 individual parasites was collected, with mean of 10.3 +/- 16.6 parasites/fish. The copepods were 37.5% of the total parasite specimens collected. Lepeophtheirus monacanthus was the most dominant species and the only species with abundance positively correlated with the host total length. Host sex did not influence parasite prevalence or mean abundance of any species. The mean diversity in the infracommunities of N. barba was H = 0.130 +/- 0.115 with no correlation with host's total length and without differences in relation to sex of the host. One pair of endoparasites (Dinosoma clupeola and Pseudoacanthostomum floridensis) showed positive association and covariation between their abundances and prevalences. The parasite community of N. barba from Rio de Janeiro can be defined as a complex of species with low prevalence and abundance and with scarcity of interspecific associations. However, because of both the presence of assemblages of sympatric ariid species as well as the spawning behavior characteristic of these fishes, additional comparative studies of the parasite component communities of ariids are necessaries to elucidate this pattern.

Assessment of the recreational linefishery in selected Eastern Cape estuaries: trends in catches and effort

Boat-based creel surveys were used to collect catch and effort data on the shore- and boat-based linefisheries of the Kromme, Gamtoos, Swartkops, Sundays, Bushmans, Kariega, Kowie and Great Fish estuaries in the Eastern Cape, South Africa, from January 1996 to April 1997. The surveys, which were performed primarily during routine fisheries law enforcement patrols by a regional conservation agency, recorded the catch and effort of 2 468 individual angler outings (12 840 angling hours) during 337 angler-count patrols. Although 26 species were recorded, a large proportion of the catch (85%) comprised only four species. Spotted grunter Pomadasys commersonnii (43%) was most commonly caught, followed by Cape stumpnose Rhabdosargus holubi (16%), dusky kob Argyrosomus japonicus (14%) and white seacatfish Galeichthys feliceps (12%). In terms of mass, the overall catch was dominated by A. japonicus (50%) and P. commersonnii (33%). Overall catch per unit effort (cpue) by number was highest during summer and lowest d...

Redescriptions of two species of Lepeophtheirus (Copepoda, Siphonostomatoida, Caligidae) parasitic on teleost marine fishes from the coastal zone of the State of Rio de Janeiro, Brazil

Two species of Lepeophtheirus Nordmann, 1832 parasitic on the ariid fish Netuma barba Lacepede, 1803, and the bothiid fish Paralichthys sp. from the coastal zone of the State of Rio de Janeiro, are redescribed and illustrated: L. bagri Dana, 1852, and L. monacanthus Heller, 1865. New junior synonyms for these species are proposed: L. marginatus syn.n., L. christianensis syn.n. and L. platensis syn.n. of L. bagri and L. unispinosus syn.n. of L. monacanthus.

Variação espacial e temporal de bagres marinhos (Siluriformes, Ariidae) na Baía de Sepetiba, Rio de Janeiro

Bagres marinhos (Ariidae) são os mais abundantes recursos pesqueiros em arrastos de fundo na Baía de Sepetiba, RJ (Lat. 22º54’-23º04’S; Long. 43º34’-44º10’W), que é uma importante área de criação e alimentação de uma grande variedade de espécies de peixes na fase juvenil. Padrões espaciais e sazonais de distribuição dos bagres marinhos, baseados no número e no peso de peixes por arrasto, foram analisados com base em 151 amostragens de arrasto de fundo, em sete locais da Baía de Sepetiba, entre julho de 1993 e junho de 1996. Para comparações espaciais da área de estudo, estabeleceu-se como zona interna a região situada no interior da Baía e como zona externa a área com maior influência das águas oceânicas. Juntamente com os arrastos de fundo, foram feitas medições da temperatura e salinidade da água de superfície e de fundo, da transparência e da profundidade. Um padrão de variação espacial baseado nos fatores ambientais, através da análise multivariada, é apresentado com maiores profundidades e transparências na zona externa e menores na zona interna, com pequeno gradiente de aumento de salinidade da zona interna para a zona externa. Somente a temperatura apresentou sazonalidade. Cinco espécies de bagres marinhos foram registradas, na seguinte ordem decrescente de abundância numérica: Genidens genidens (Valenciennes, 1839), Cathorops spixii (Agassiz, 1829), Sciadeichthys luniscutis (Valenciennes, 1840), Netuma barba (Lacépède, 1803) e Bagre marinus (Mitchill,1814). Um padrão de variação espacial na distribuição dos bagres marinhos na Baía de Sepetiba foi apresentado, com as quatro mais abundantes espécies distribuindo-se principalmente na zona interna da Baía, com indicações de separação espacial entre as mesmas. G. genidens foi abundante em todas as estações de coleta da zona interna da Baía, C. spixii apresentou distribuição mais restrita na zona interna e N. barba, nas proximidades da embocadura do Rio Guandú, enquanto S. luniscutis apresentou ampla distribuição na zona interna e externa da Baía.A sazonalidade não foi marcada para essas espécies. Estratégias de separação espacial podem estar explicando a coexistência em elevada abundância de bagres marinhos na Baía de Sepetiba, que funciona como área de criação desses peixes, os quais encontram nas menores profundidade e transparência da zona interna condições favoráveis para o desenvolvimento de seus ciclos de vida.

Present state and perspectives for the southern Brazil shelf demersal fisheries

AbstractThe demersal fish stocks in southern Brazil were assessed from landings and catchper‐unit effort data trends between 1975 and 1994, available information on the life history patterns, and population dynamics of the most important species. The fishing gears, mostly otter and pair bottom trawls in the 1970s, diversified towards double‐rig trawls for fish and shrimp and bottom gill nets in the mid 1980s, and bottom longlines in the upper slope in the early 1990s. There were also some less successful attempts with traps for fish and crabs. The demersal fisheries are more intensive in winter when migratory species move northward, associated with the seasonal displacement of the western boundary of the Subtropical Convergence. Landings between 1975 and 1994 were mostly of sciaenid fishes (>70%) and elasmobranchs (10%) and oscillated around 59 000 t. There was not a decrease in total landings but a shift from more to less exploited stocks. Since 1989, 4% of the landings came from depleted stocks of Pagrus pagrus (L.), Netuma barba (Lacépède), Pogonias cromis (L.) and Rhinobatos horkelli (Muller & Henle); 37% from overexploited stocks: Micropogonias furnieri (Desmarest), Paralichthys patagonicus Jordan, Squatina guggenheim Marini, and Galeorhinus galeus (L.); 24% from heavily exploited stocks of Umbrina canosai Berg, and Macrodon ancylodon (Bloch & Schneider); and 35% of Cynoscion guatucupa (Cuvier) and small stocks with unclear status. The demersal fisheries are virtually unmanaged and future landings are expected to decrease if fishing pressure remains high. Effective management will require the participation of all three countries in the region because most of the stocks fished in southern Brazil are shared with Uruguay and Argentina.

Insulin secretory on isolated pig islets

Catfish Genidens barbus is a commercially fished species from the south-western Atlantic Ocean. Overfishing of this species during the last few years has caused a collapse of fisheries and in turn has led to a ban of its exploitation. In order to identify the migratory patterns of this species in four migration corridors from South America, we determined the Sr:Ca and Ba:Ca ratios in otoliths, by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS). Sr:Ca and Ba:Ca ratios range between 0.90 and 9.83 mmol/mol (mean ± standard deviation: 3.86 ± 1.05 mmol/mol) and between 0.00013 and 0.10 mmol/mol (mean ± SD: 0.0094 ± 0.0160 mmol/mol), respectively. Three types of amphidromous and cyclical (annual) patterns that include the use of freshwater, estuarine and marine environments are detected. Resident freshwater fish (6.5%) are found only in Patos Lagoon. Depending on the study site, between 18 and 45% of the analyzed fish population were spawned in freshwater, while the rest were spawned in estuarine waters. The change-point analysis shows a positive correlation between changes in the transects of Sr:Ca and Ba:Ca ratios (r = 0.63, p = 0.0001), whereas the Kruskal-Wallis test shows no significant differences in the number of changes in transects of the Sr:Ca ratio between sampling sites (H = 2.1, p = 0.53). Only for Patos Lagoon the analyses show a significantly higher number of changes for the Ba:Ca ratio (H = 9.1, p = 0.03). The data indicate that the average number of movements among environments is similar between the four corridors. The number of changes of the Ba:Ca ratio appears to be higher and more variable in relation to the Sr:Ca ratio, indicating that the former could be more sensitive to environmental changes. In conclusion, this work describes for the first time, annual amphidromous migrations and dependence on freshwater for different fluvial-marine systems. The understanding of the habitat use will help design species and estuarine-specific management actions with the ultimate goal of recovering fisheries.

Changes in body composition associated with growth and reproduction inGaleichthys feliceps(Teleostei: Ariidae)

White seacatfish Galeichthys feliceps were collected from four Eastern Cape estuaries and the sea. Males utilized estuarine mouth regions for egg incubation, which peaked from September to December. The energy expended in mouth-brooding amounted to 8 per cent of male body energy (27% of body fat). The amount of energy invested in functional egg production equalled 26 per cent of female body energy (fecundity 70 ± 13). There was an increase in energy of fish bodies as body length increased whereas embryo energy decreased as development progressed.

Dinosoma clupeola sp. n. (Hemiuridae) and Pseudoacanthostomum floridensis Nahhas & Short, 1965 (Acanthostomidae), digenetic trematodes in Brazilian Marine fishes

Dinosoma clupeola sp. n. is described from Harengula clupeola, and resembles D. hawaiiense Yamaguti, 1970, from which it differs in the entire, elongate-saccular seminal vesicle, tegument weakly plicated, smaller size of body and internal organs, and slightly larger and narrower eggs. Pseudoacanthostomum floridensis Nahhas & Short, 1965 is referred to Netuma barba, which represents a new host record.

Distribuição, abundância relativa e movimentos sazonais de bagres marinhos (Siluriformes, Ariidae) no estuário da Lagoa dos Patos (RS), Brasil

Three ariid fish, Netuma barba, Netuma planifrons and Genidens genidens, use the estuary of the Patos Lagoon (32oS), Rio Grande do Sul, Brazil, as a nursery and feeding ground in various stages of their life history. A comparative study was made of the temporal and spatial distribution and relative abundance. Seasonal movements were interpreted on the basis of distribution and abundance of the young of these coexisting sea catfishe. Monthly otter trawl samples were made between November, 1979 and April, 1983. Temperature, salinities and dissolved oxygen contents were taken at each of the 674 sample stations. All three species were caught in ample temperature (12,1 to 26,3oC), salinity (0,3 to 35,5‰) and dissolved oxygen (4,7 to 11,5 mg/l) ranges. However, they were more abundant in stations of low temperature and in salinity with highly dissolved oxygen content. N. barba was the most abundant catfish caught in the estuary, it constituted 81,9% in number and 81,4% in weight of ali ariid trawl catches during the study. N. barba occurred throughout the estuary, from the adjacent coastal region to the upper reaches of the Patos Lagoon estuary near the liminetic zone. N. planifrons occurred from adjacent coastal regions to low saline parts of the Patos Lagoon estuary, whereas G. genidens were distributed mainly in low saline and freshwater parts of the lagoon. Young-of-the-year N. barba aggregated near of the entrance of the lagoon in fall and winter, then moved up to intermediary parts of the estuary in spring, and they went to the upper part of the estuary in summer. Yearlings N. barba moved into the estuary in common with young-of-the-year but did not reach the coastal adjacent area. Young-of-the-year and yearling N. planifrons moved in to the estuary as the same pattern as N. barba but they became scarce during the late summer and early fall. G. genidens were scarcely captured in the estuary throughout the year. The spatial and temporal segregations among Netuma and Genidens were evident. A hypothetical model for the life history of N. barba is suggested.