Study On Fishery Resource And Ecology Of WuLanNuoer Reservoir In Inner Mongolia

Overall investigation of physiochemical features and fish community structure and fisheries resources and biological factor of reservoir water quality were conducted during 2006 to 2007 in Wulannuoer Reservoir. At the basis of these investigations, integrate evaluation of trophic state and environmental status was made. Theoretical base for the reasonable utilization of fishery resource and ecological management of environment were provided. The main results are as follows:1. The average water depth, water temperature and turbidance seven stations in the reservoir was 152.06 cm, 11.4℃and 20.89 FTU, respectively. Mean pH value was 7.92;the average content of DO was 7.11mg/L;ALK and Hd were 11.67 mmol/L and 6.04 mmol/L, respectively. The mean concentration of NH4+(NH3)-N,NO3――N,NO2――N and PO43-—P were 1.384,0.474,0.079 and 0.187 mg/L, respectively. The content of TP and TN averaged 0.159 and 0.233 mg/L, respectively.2. There were 30 species of phytoplankton. The average phytoplankton biomass was 7.88 mg/L in wet weight. Phytoplankton was dominated by Cyanophyta and Chlorophyta according to biomass.3. There were 28 species of zooplankton. The average biomass of zooplankton was 3.86 mg/L. There was no pronounced relationship between the standing crops of zooplankton and of phytoplankton (p>0.05); so phytoplankton cannot be well controlled only depending on zooplankton.4. Fourteen species of fish exist in the reservoir, mainly Common carps, Crucian, Catfish and the Whitefish economically, three of which were analyzed. Whether from the point of the economy or ecology, there is inconsistence in the construction of the fish population.5. According to water physiochemical features, biomass and indication species of every kind of organisms, the trophic level of Wulannuoer Reservoir is of eutrophic type; and has the trend of future eutrophication. It is suggested the following measures should be taken: strengthening the stocking of fish which is fed on phytoplankton and adjusting the structure of minor carnivorous fish. Then the utilization of nutrients in the reservoir and output of trophic load from the water will be improved. Thus more economic benefit can be achieved as well as the environment can be protected. The strategy for the fishing industry environmental protection was proposed to provide theory for the sustainable development and guide for the practice.