Water environment change over the period 2007-2016 and the strategy of fishery improve the water quality of Lake Taihu

Abstract

Currently, water environment in the Lake Taihu has become one of the focuses due to its importance to the rapid growth of economy and the process of society in the Lake Taihu Basin. "Water Crisis" of the Lake Taihu in 2007 has resulted in a series of comprehensive treatment program for its eco-environmental improvement. Based on the water quality data from 2007 to 2016, the characteristics and dynamic variation of water environment in the last decade were analyzed. The results showed that the periodic change of water quality in Lake Taihu was obvious. All water quality indexes continued to decline and then leveled off over the period of 2008 to 2012, while certain indexes, such as total phosphorus and chlorophyll-a concentration, showed a rapidly increasing trend in nearly three years. Additionally, the spatial heterogeneity of water quality in the Lake Taihu decreased. As for the heavily polluted northwestern waters, changing from "contaminated" to "natural" status, had acquired a massive improvement in the ecological environment, while the water quality of the southeastern waters had gradually deteriorated. Based on the correlation analysis between the fish community structure and water quality variation in Lake Taihu, and combined with the practice of certain fish bio-manipulation projects in local lake regions, a bio-manipulation approach "Fishery improve the water quality" combined using traditional and non-traditional bio-manipulations was proposed. Eutrophication control in lakes requires sufficiently concern the irreplaceable role of fish in driving plankton community and water quality modification, as well as considering the advantageous effects of structural optimization of fish community and food web manipulation.