Survey of fishery ecology in Yingnahe Reservoir in Dalian

The water quality,communities of aquatic organisms and evaluation of fishery productivity were studied in Yingnahe Reservoir in summer,autumn,winter and spring from 2002 to 2003.The Yingnahe Reservoir as a phosphorus limiting reservoir was found to be eutrophication waters with N∶P ratio of 62.62.A total of 151 taxa of phytoplankton and 83 taxa of zooplankton were identified in Yingnahe Reservoir.There were abundance of phytoplankton of 2.5×107 ind./L and biomass of 10.58 mg/L.The diatom and green algae were of the predominant phytoplankton species.The abundance of total zooplankton was 992 ind./L and the biomass of 4.21 mg/L.The predominant zooplankton were cladocera and copepoda.The density of picoplankton reached(0.73-5.80)× 107 ind./L,and the total abundance of bacteriaplankton 2.57×107 ind./L,the peak in summer(5.78× 107 ind./L).There was 2.53 ×106 ind./L of heterbacerria.Five taxa of benthos were identified with mean density of 471 ind./m2 and biomass of 1.21 g/m2.The predominant species were Pelopia and Limnodrilus hoffmeisteri.Two species of water macrophytes,39 fish species and 2 shellfish species were distributed in Yingnahe Reservoir.The eutrophic situation,and fishery productivity were discussed.