Effect of pen aquaculture on community structure and species diversity of zoobenthos in Gehu Lake

The community structure, distribution and species diversity of zoobenthos in the Gehu Lake, Jiangsu were investigated in April, July, November 2002 and January 2003. The results showed that in the lake there were totally 31 species of zoobenthos, including 14 species of mollusks, 6 oligochaetes, 7 aquatic insects and 4 leeches, and of them, Bellamya purificata and Chironomus plumosus were the dominant species; the community structures of zoobenthos in pen fish-farming zone in the northern part and pen crab-farming zone in the southern part of the lake were very similar, but greatly different from non-aquaculture zone ; and the species diversity of zoobenthos was found declining from south to north of the lake, and from low temperature seasons to the warm seasons.