Research on Phytoplankton Community Structure and Its Potential Fishery Productivity of Sandaohe Reservior

The temporal-spatial distribution pattern and the composition of phytoplankton communities in Sandaohe Reservior were investigated during the period of Aug.2007 to Apr.2008.The phytoplankton diversity and potential fish production were assessed accordingly.A total of 79 species of phytoplankton belonging to 49 genera and 8 phyla were observed in this reservoir and it was mainly composed of chlorophyta,bacillariophyta and cyanophyta.The phytoplankton species in respective sampling stations varied from 43 to 56,but with similar composition proportion.The seasonal composition of phytoplankton species was significantly different,with the highest species number in autumn and the lowest in winter.The annual average density of phytoplankton was 20.33×104 cells/L with an annual biomass of 0.21 mg/L.The mean annual Shannon-Wiener diversity index and the Pielou evenness index were 2.10 and 0.85,respectively,with its maximum in winter and minimum in autumn.According to the water quality assessment criteria based on the phytoplankton,Sandaohe Reservior is mesotrophic and the potential fishery productivity provided by phytoplankton is estimated to 9 072.45 kg(22.68 kg/hm2) in total.