Study On Waters Environment And Sustainable Fisheries Development In Dongjiang Lake

From2006to2007, the Dongjiang Lake was general invested on waters environment according to Surface Water Environmental Quality Standard and Fisheries Water Environmental Standard, including pHysical and chemical factors (such as TN, TP, heavy metals, etc.) and primary productivity. The results show that Dongjiang Lake had multi-function including providing waters or space for drinking water, fisheries, shipping, tourism, agriculture, irrigation; and its waters was belong to the grade Ⅱ of surface water, its heavy metals concentration were belong to grade Ⅰ if each of parameters’concentration was under mean; the annual yield of filter fish could reach1541.9t. But the significant difference exist among various sampling sites, such as TN0.22mg/L～2.30mg/L therefore the waters of some sampling sites was worse than surface waters grade V, meanwhile the TN concentrations were the highest as summer; the top concentration of TP was0.0419mg/L which was belong to surface water grade Ⅲ; and the concentrations of Cu, Cd, Zn at some sites were not qualified with Fisheries Waters Quality Standard, also Cd concentration were not eligible with surface water grade Ⅲ and grade V at some sites; the integrated pollution index revealed that the big different of water quality was exist among sampling sites, and the biggest polluting contribution was TN. The research shows that waters quality (concentration of heavy metals) could be ensured to be surface water grade Ⅱ by controlling the discharging waste water from ambient factories; carbon singking fisheries can be developed and water nutritive level can be reduced by taking full advantage of TN&TP resources and protecting aqua-plants; developing nuisanceless fisheries and guarantying sustainable fisheries development in Dongjiang Lake by carrying good regulations into practice. Fish multiplication releasing and catchment analysis showed that releasing pelagic filter-fish could increase value of output and also purify the water environment in the case of not applying any fertilizer.