[Structural characteristics of crab communities in offshore waters of mid-southern East China Sea].

The crab resources in the offshore waters of mid-southern East China Sea (26 degrees 00'-28 degrees 30' N, 121 degrees 00'-126 degrees 00' E) were investigated in May (spring), August (summer), November (autumn) 2006 and February (winter) 2007, with the characteristics of their community structure, including species composition, index of relative importance (IRI), diversity, and biomass analyzed. A total of 49 species were identified, belonging to 30 genera and 12 families. In both spring and autumn, the crab species number was higher in northern than in southern part of the Sea; in summer, it had a relatively uniform distribution; while in winter, less difference was observed between the southern and northern parts of the Sea, and the crabs were mainly concentrated in the exterior areas.