Abstract: To provide basic information for further reservoir management and restoring, the community structure of zooplankton including species composition, biomass, density, diversity index and chemical and physical parameters were studied monthly in Fenshuijiang Reservoir of Zhejiang province from October 2008 to December 2008. A total of 23 zooplankton species were identified, including 11 Rotifera (48% of the total ), 6 Cladocera (26% of the total ) and 6 Copepoda (26% of the total ). The dominant species mainly were Keratella cochlearis, Asplanchna priodonta, Bosmina longirostris and Mesocyclops dissimilis during this period. The average density of zooplankton ranged 78.0~297.3 ind./L, and the average biomass ranged 2.044~8.924 mg/L in Fenshuijiang Reservoir. The results in this study indicate that the water quality of the Fenshuijiang Reservoir is between α and β type of medium pollution, based on the biological parameters including the qualitative and quantitative analyses of zooplankton community, biodiversity indexes and chemical parameters with integrated pollution index and chemical evaluation index. It was suggested that the further work should be carried out to strengthen the current reservoir ecosystem.

Key words: community structure, biodiversity index, water quality assessment, zooplankton, community structure, biodiversity index, water quality assessment