Life table of mangrove crab, Ucides cordatus (Linnaeus, 1763) (Decapoda: Ucididae) in the Coreaú River mangrove, Northeast Brazil

Abstract

The hypothesis of this study is that males of Ucides cordatus belonging to the largest size classes have higher mortality rates than smaller individuals, due to fishing selectivity. The prediction is that the survival curve for the species is type I, characterized by high survival in intermediate and smaller age classes/sizes, followed by a decrease when close to longevity/maximum size, what was tested by the life table method. Crabs were sampled bimonthly from January 2004 to January 2005 in the Coreaú river mangrove, Ceará State. The animals were captured by the braceamento technique and had the carapace width measured for setting up its correspondent size frequency distribution. To construct the life table, the number of dead individuals through catching was counted by size-class, followed by the estimation of the other table parameters. The results indicated a higher percentage of survivors in the smaller size classes and a high mortality in the larger classes, confirming our prediction of type I for the generated survival curve.