Community structure and species diversity of crab in middle East China Sea

On the base of the survey data of beam shrimp trawl in 4 seasons of 2008 and 2009 in the East China Sea,we study the seasonal characteristics of community structure of crabs in that sea area.Thirty crab species belonging to 9 families and 16 genera were caught;the average weight of catch is 3 173.05~9 835.67 g per haul.The dominant species are Charybdis bimaculata,Ovalipes punctatus(perennial),Portunus argentatus and Charybdis miles.The species richness index(D) is 0.09~1.41,the Shannon-Wiener index(H′) is 0.02~1.67,and the species evenness index(J′) is 0.02~1.00.No significant difference is found in the diversity indices among 4 seasons(P0.05).