Abstract: A monthly investigation was conducted on the macrozoobenthos at 7 stations of Fenshuijiang Reservoir in Zhejiang Province of East China from November 2008 to October 2009. A total of 37 taxa were collected, most of which belonged to Oligocheata and Chironomidae. Limnodrilus hoffmeisteri was dominant in spring, summer and autumn, and Chironomus gr. plumosus was prevailing in winter. The  collectorgatherer was the predominant group in  species number, density and biomass. The mean annual density and biomass of the community were (488.0±48.8) ind·m^-2 and (1.86±0.49) g·m^-2, respectively.  There were no significant differences in the macrozoobenthic density among the stations and in the macrozoobenthic biomass among the stations and among the seasons, but the macrozoobenthic density had a significant seasonal variation, with the sequence of spring > summer > winter > autumn.  Water temperature and water depth were the main factors affecting the spatial distribution of the macrozoobenthos.  Shannon index and Goodnight-Whitley index were not suitable for the assessment, whereas the  Wright index, Carlander index,  Pielou index and trophic level index showed that this reservoir was slightly polluted.

Key words: macrozoobenthos, community structure,  , biomass, functional feeding group, bioassessment of water quality, Fenshuijiang Reservoir.