Lake Taihu is the third largest freshwater lake in China, located at 119°53′45″～120°36′15E and 30°55′42″～31°31′55N with an area of 2428 km2 and the average water depth of 1.89m. It is the most typical large shallow lake in the lower reaches of Yangtze River, and plays the important roles in the watershed such as the drinking water source, flood control, fish culture, irrigation and tourism. The fishery is one of important functions in Lake Taihu，which includes fish catching and enclosure culture. In the recent twenty years, over-fishing and the large-scale expansion of the enclosure culture have significantly affected the biological resources and led to water quality deterioration in Lake Taihu. Based on the remote sense photographs of Lake Taihu, the area of aquaculture in East Taihu Bay is estimated to be 10647.02hm2 in 2003, occupied 79.25% of the total area of the Bay. Meanwhile, according to the current status, the potential yield estimates of the biological resources in Lake Taihu is 113.93 kg/hm2, i. e. total annual catch of 27662 t. Based on the nutrient budget of the lake and nutrient uptake ability of macrophytes, the suitable area of fish enclosure culture is estimated to be less than 2094hm2 in East Taihu Bay. For crab enclosure culture, the area is 3210 hm2,meanwilde a herbivorous fish culture of 281hm2 is needed for taking up the aquatic plants from crab enclosure.
The bases of fishery region classification of Lake Taihu are the lake environment, the bioresource distribution and the function. Lake Taihu can be divided into three functional regions which include the eastern core area for resource protection, the buffer area with natural wetlands, and the western restoration area. The eastern core area for resource protection includes the protection area of fish reproduction, the protection area of icefish resources, the protection area of snail and corbicula resources, the stocking area of fish fingerling, the protection area of biodiversity, the forbiding area of fishing gear fixation and the enclosure culture area, and the total area is 437.6km2. In western wetlands and the partial area of East Taihu Bay destructed by enclosure culture, it is important to establish a restoration area, having an area of 282.5km2. This regional classification is to help improve the lake’s water quality and protect the fishery resources, biodiversity, and the natural wetlands. In order to promote the fishery development of Lake Taihu, the ecological fishery management countermeasures were proposed, including controlling the types of fishing gear and fishing intensity, adjusting the fishing season, controling stocking fish species. Regarding to the enclosure culture in East Taihu Bay, the important measures are to strictly control the scale of enclosure culture, select right culture species, and incease the culture proportion of high valued aquatic species.and reduce the pollution from the culture. The ultimate goal of regional classification and functional positioning of Lake Taihu is to attain rationale and sustainable utilizations of the fishery resources in Lake Taihu.