IDENTIFICAÇÃO, ABUNDÂNCIA E DISTRIBUIÇÃO DAS FASES LARVAIS DAS ESPÉCIES DE BRACHYURA (CRUSTACEA, DECAPODA) NO ESTUÁRIO DA LAGOA DOS PATOS E REGIÃO COSTEIRA ADJACENTE.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Composition, abundance and distribution of the pelagic phases of the Infraorder Brachyura found in the estuarine region of the Patos Lagoon and nearby coastal region, were studied during 1995 and 1999. A conical net (165 cm long, 60 cm mouth, and 330 μm mesh, equipped with a flowmeter) towed for three minutes at 3 knots was used to sample. at least five stations in the estuary and two stations of the coastal region. Sampling was carried out on surface and deep waters. At each station, surface and bottom salinity and temperature were recorded. In 1995, zoeae of 16 species (eight families) were caught, resulting in a total abundance of 36034.17 ind./100 m, from which 14811.82 ind./m and 21222.35 ind./m were found in surfacel and deep waters, respectively. Megalopae of 20 species (seven families) were caught, resulting in a total abundance of 2086.85 ind./100 m, from which 190.3 ind./m and 1896.55 ind./m were found in superficial and deep waters, respectively. In 1999, zoeae of 11 species (six families) were caught, resulting in a total abundance of 13486.85 ind./100 m, from which 7234.34 ind./m and 6252.01 ind./m were found in surface and deep waters, respectively. Megalopae of 11 species were caught, resulting in a total abundance of 2611.63 ind./100 m, from which 368.05 ind./m and 2243.58 ind./m were found in surface and deep waters, respectively. Summer was the most abundant season in both years. In 1995, 78.44% of the zoeae and 83.14% of the megalopae found were caught in the summer, while in 1999 55.81% of the zoeae were caught in the summer. During Autunm megalopae was most abundant in 1999, summing up 56.08% of the total catch. These results suggest a higher reproductive activity, and recruitment, in warmer seasons. Winter was the season in which data suggest the weakest reproductive activity. 4 Considering the identified species of Xanthoidea, the most abundant species was Hexapanopeus caribbaeus. In 1995, this species summed 84.09% and 79.63% of the total catch of zoeae and megalopae of this superfamily, while in 1999 figures were 41.88% and 89.10%, for zoeae and megalopae, respectively. For Grapsoidea, Chasmagnathus granulatus was the most abundant species, comprising 76.37% and 66.13% of the zoeae, and 76.37% and 66.13% of the megalopae caught in 1995 and 1999, respectively. The genus Pinnixa showed the highest percentage of zoeae (78.04% and 77.27% in surface and deep waters, respectively) in the year of 1995, while in 1999 the percentage of zoeae of this genus was 48.23% and 54.61%, in surface and deep waters, respectively. It was not possible the identification of megalopae of Pinnixa spp. It was observed a year round spawning only for Chasmagnathus granulatus and Pinnixa spp.. An unreported spawning strategy was observed for Callinectes sapidus, in which during spring and summer, spawning was observed into the estuarine region of the Patos Lagoon. Schematics diagrams of larval phases dispersion and re-invasion were elaborated to each Superfamily and to species of Superfamily Portunoidea.

ASSUNTO(S)

abundância estuary patos lagoon distribution oceanografia biologica chave de identificação estuário da lagoa dos patos fases larval brachyura brachyura larval phases identity key distribuição abundance

ACESSO AO ARTIGO

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