Decapod crustaceans from a marine tropical mangrove ecosystem on the Southern Western Atlantic, Brazil

The purpose of the present study was to investigate the biodiversity, relative abundance and frequency of decapod crustaceans in the marine mangrove ecosystem at Gaibu Beach, Pernambuco State, Brazil. A total of eight samples were taken: four in the rainy season (August 2010) and four in the dry season (February 2011), during spring low tides and according to the phases of the moon. In all, 352 decapods were sampled. These specimens belonged to 17 species, 14 genera and 13 families. Pachygrapsus transversus (Gibbes, 1850), P. gracilis (Saussure, 1858), Panopeus americanus Saussure, 1857 and Uca (Leptuca) leptodactyla Rathbun, 1898 were very frequent. The three latter species occurred in all samples. The most abundant species was P. americanus. The Shannon-Wiener index (H') showed that, in general, the diversity level was medium for all samples. However, the sample taken at the time of the new moon during the rainy season was classified as highly diverse. These results contribute to the knowledge of the decapod fauna inhabiting mangroves associated with fringe reefs