Bioecology of the crab Ucides cordatus (Crustacea, Decapoda) in mangroves influenced by the Amazon River, Brazil

The mangrove crab (Ucides cordatus) is a valuable fishery resource, overfished along the Brazilian coast. This study aimed to obtain bioecological data on this crab along the coast of the State of Amapa. Six bimonthly samplings were conducted between December 2008 and January 2010. Transects were used to estimate the density (burrows m super(-2)) and population abundance (individuals m super(-2)). All the animals were subjected to biometrics, with females being classified according to their stage of gonadal maturation. The mean density (1.09 burrows m super(-2)) and abundance (0.31 individuals m super(-2)) were influenced by the climate with the highest values in summer (1.17 burrows m super(-2) and 0.34 individuals m super(-2)). The male to female ratio was 1.38:1 showing significant difference in the proportion of sexes. The individuals showed sexual dimorphism, with linear measurements significantly higher in males. The sampled animals also had larger carapace length and width (CL and CW) compared to crabs studied in other Brazilian states. There was a positive relationship between CW and CL and individual weight (IW) and CW for males (R super(2) = 0.83 and 0.90) and females (R super(2) = 0.79 and 0.84). The growth was negative allometric (CL increases to a lesser extent than CW) for both sexes. The highest frequency of ovigerous females (78%) and in maturation stage IV (38%) occurred in the CW size class between 59.8 and 67.5 mm. The peak of mature females occurred in May and August, showing a reproductive period different from those in other Brazilian states.Original Abstract: O caranguejo-uca (Ucides cordatus) e um valioso recurso pesqueiro, sobreexplorado ao longo do litoral brasileiro. O objetivo deste trabalho foi obrer dados bioecologicos deste caranguejo em toda a costa do Estado do Amapa. Foram realizadas seis coletas de frequencia bimensal, compreendidas entre os meses de dezembro de 2008 a janeiro de 2010. Por meio de transectos foram estimadas a densidade (tocas m super(-2)) e a abundancia (individuos m super(-2)) populacional. Todos os animais foram submetidos a biometria, sendo somente as femeas, classificadas quanto ao estagio de maturacao gonadal. A densidade (1,09 tocas m super(-2)) e a abundancia (0,31 individuos m super(-2)) foram influenciadas pelo clima, sendo os maiores valores observados durante o verao (1,17 tocas m super(-2)e 0,34 individuos m super(-2)). A razao sexual foi de 1,38M:1F, mostrando diferenca significativa entre a