Estrutura e diversidade da comunidade de Callinectes Stimpson, 1860 em estuários da amazônia brasileira.

Abstract

The swimming crabs of the genus Callinectes Stimpson, 1860 are economically exploited crustaceans in estuaries and bays throughout the Americas. There are approximately 300 species of Decapoda of Portunidae family that occur in the Western Atlantic. Of these, 20 are found on the Brazilian coast and 11 are found on the coast of Pará. In Brazil there is a great potential for fishing for species of the genus Callinectes, and the catch is practiced by small artisanal fishing communities distributed throughout the coast. Because of the great diversity and ecological and economic importance to the crabs of the genus Callinectes have the northern Brazilian coast, it is necessary information about the structure and diversity of crabs of the genus Callinectes in estuaries of the Brazilian Amazon, for a sustainable yield. Samples were taken monthly in the period of october/2011 to december/2012 in estuaries of the municipalities of Vigia de Nazaré, Salinópolis and Bragança. Four species of crabs caught were identified: Callinectes bocourti A. Milne Edwards, 1879, Callinectes danae Smith, 1869 Callinectes exasperatus Gerstaecker, 1856 and Callinectes ornatus Ordway, 1863. C. bocourti was the most representative, accounting for 72% of the total catch. Males accounted for 64.72% of the specimens analyzed in the catches of this work, and C. exasperatus was more representative as the number of females captured. The study records the first occurrences of C. exasperatus in studies at estuaries of Pará. Identifications occurred in the Crustaceans Laboratory of Centro de Pesquisa e Gestão de Recursos Pesqueiros do Litoral Norte. The 1.043 identified specimens were distributed among: Callinectes bocourti (n = 751), C. danae (n = 252), C. exasperatus (n = 37) and C ornatus (n = 3). In Vigia de Nazaré was verified a lower richness (n = 2) in relation to Bragança and Salinópolis (n = 4). The Shannon diversity index was 1.15 bits.ind-1 in Bragança, 1.22 in Salinópolis and 0,02 bits.ind-1 in Vigia de Nazaré. The evenness was 0.57 in Bragança, 0.61 in Salinópolis and 0,02 in Vigia de Nazaré. The crabs were found preferentially in the dry season.