在小水体精养中 ,由于饵料、药物的频繁施加使养殖水体逐渐富营养化 ,水质恶化日益严重 ,继而造成养殖特色品种的质量下降 ,于是 ,人们转向了大中水域的特色养殖。目前一些水库由于人为因素 ,鱼、虾、蟹类等生物数量在减少 ,浮游生物过量繁殖 ,破坏了生物链和水体的生态平衡 , In the small water body intensive cultivation, due to the frequent application of food and medicine, aquaculture water gradually eutrophication, water quality deterioration worsening, then causing the quality of breeding breeds decline, so people turned to the characteristics of aquaculture. At present, due to human factors in some reservoirs, the number of organisms such as fish, shrimp and crabs is decreasing, overproduction of plankton and the ecological balance of biological chains and water bodies are damaged,