Lake Qiandaohu, Zhejiang is a large and deep lake in the middle and lower reaches of the Changjiang River, China. We made a survey on the species composition, density, biomass and diversity index of zooplankton in Lake Qiandaohu. Zooplankton samples were taken at monthly interval from ten stations from January-December 1999. At each station, two kinds of samples were taken, one for identifying species and the other for determining abundance of zooplankton. The frist kind of sample was the mixture of five su...