[Effects of Optimized Fish Farming on the Sediment Nutrients of Eastern Lake Taihu].

ABSTRACT

The farming of lake fisheries is an important part of the freshwater fishery industry in China. However, farming patterns of traditional fisheries maintain serious negative effects on the ecosystem of Eastern Lake Taihu. In recent years, the enclosure culture model of this lake has been optimized. In order to investigate the effects of aquaculture on the sediment properties, samples were collected from different areas of the lake (i.e. within the culture areas, outside the culture areas; from the crab-plant co-culture areas, mixed culture areas, ecological restoration areas, and control areas), in different months (January, March, April, August, and November), and at different depths (0-1 cm and 9-10 cm). The results of this sampling indicates that ① the concentrations of total nitrogen (TN) and total phosphorus (TP) in the sediments samples collected within the culture areas are slightly higher than samples collected outside the culture areas; ② compared to the crab-plant co-culture areas, lower concentrations of TN and TP are found in the samples collected from the mixed culture areas; ③ in the ecological restoration areas, aquatic plants exhibit certain positive effects with decreasing concentrations of TN and TP in the sediment. The lowest concentrations of TN and TP are detected in the sediment during the growing season of aquatic plants.