<b>Comparison of natural diet of blue crab <i> Callinectes sapidus </i> Rathbun, 1896 (Crustacea: Decapoda: Portunidae) in two places at Patos Lagoon estuary, RS, Brazil </b>

Abstract

The blue crab Callinectes sapidus Rathbun, 1896 is the most abundant species of genus in the estuarine region of Patos Lagoon, considered as key benthic predator. This study aims to compare the natural diet of the blue crab between two sites in the estuary of Patos Lagoon. Samples were collected in February and May 2009 by using an otter trawl towed during 15 minutes. In the laboratory, the intestines were weighed and assessed the degree of fullness. The contribution of each food item was analyzed by using the frequency of occurrence and relative frequency of points. The comparison between both sites was performed using G test with Williams correction factor (p <0.05). At Bandeirinhas were identified in 18 items, the rest were more occurring plant Erodona mactroides, Heleobia australis and Brachyura. At Saco da Mangueira 12 items were identified, among the rest are occurring plant Erodona mactroides and shrimp. Difference was found among the items occurring in the diet according to the collection site. The blue crab is characterized by opportunistic generalist, its diet differs according to prey availability in the environment