通过2007年3月至12月对东太湖三个不同养殖密度和规模网围养蟹区养殖状况与环境的比较研究,分析不同养殖方式所带来的经济效益以及对湖泊环境的影响.结果表明:东太湖人工投饵单养河蟹的养殖方式,会造成水体氮磷营养盐累积,对水体造成污染.选取的A、B、C三个养殖区每产出1kg河蟹造成湖区氮累积量分别为0.24kg、0.33kg和0.30kg;磷累积量为0.043kg、0.059kg和0.051kg.比较各养殖区环境状况、经济效益以及河蟹生长规格,认为东太湖实施河蟹优化养殖的适宜密度和单个网围面积为6000只/hm<sup>2</sup>和2.33hm<sup>2</sup>左右,但是目前东太湖养殖方式仍需要改进.针对东太湖养殖面积过大和布局不合理现状,认为东太湖网围养蟹面积应控制在3165.2hm2以下为宜.;Based on the comparative studies between the enclosure culture situations of different density and scale of water environments investigated during period from March and December 2007 in East Lake Taihu, the paper analyzed the economical benefit and environmental effect under different culture models. The results showed that culture models of bait casting and monoculture in East Lake Taihu, no matter which kinds of density and scale there were, would make the output of nitrogen and phosphorus nutrients less than the input, and mass-input of exogenous nutrients would cause pollution effect on water quality. An estimation of nutrient contributions in three enclosure crab culture areas A, B and C showed that 1kg crab production has created 0.24, 0.33 and 0.30kg nitrogen and 0.043, 0.059 and 0.051kg phosphorus into the lake, respectively. According to the comparisons of environmental situations of economic benefit and growth specification of the enclosure crab culture in East Lake Taihu, a reasonable density of the optimized model is 6000 crab/ha and the single enclosure is 2.33 ha/each, while the current culture manner should be improved. For too large scale and unreasonable distribution of enclosure culture in East Lake Taihu, we suggest that the area of enclosure crab culture should be controlled under 3165.2 ha.