美国生态水产养殖模式与常规混养模式的环境效应比较

Comparison Between American Ecological Aquaculture and Traditional Polyculture in Environmental Impact

在江苏省扬中市开展池塘养殖试验,以草鱼为主养鱼种,比较研究美国80:20生态水产养殖模式(养殖占80%渔获量的单种主养鱼和20%的滤食性鱼类)与传统混养2种模式对池塘水质和底质的影响。试验结果表明,生态养殖池塘鱼类产量和经济效益显著优于传统混养。生态养殖池塘COD、TP、TN、NH3-N和NO2--N等重要水质指标全年平均质量浓度分别为21、0.12、2.06、0.340、0.021mg·L-1,明显优于传统混养模式的25、0.15、2.56、0.706、0.113mg·L-1;BOD5、PO43--P、NO3--N和叶绿素a含量则无显著差异。生态养殖池塘底泥厚度比传统混养池塘减少了12.5%,底泥中有机质含量较传统混养池塘高11.2%,TP和TN含量分别降低13.5%和5.1%。80:20生态养殖模式较传统混养体现出明显的优势。

An aquaculture experiment was carried out in Yangzhong,Jiangsu Province,with grass carp as the principal fish,to compare ecological aquaculture with traditional polyculture in impact on water quality and sediments.It was found that the former was obviously superior to the latter in yield and economic profit.The annual mean values of some of the water quality indexes,such as COD,TP,TN,NH3-N,and NO2--N were measured to be 21,0.12,2.06,0.340 and 0.021 mg·L-1 for the ponds of US 80：20 ecological aquaculture,and 25,0.15,2.56,0.706 and 0.113 mg·L-1 for the ponds of traditional polyculture.Obviously the former was better than the latter,respectively.No significant differences were found in contents of BOD5,PO43--P,NO3--N and chlorophyll-a.The bottom sediment was 12.5% thinner in the ponds of the US 80：20 ecological polyculture than in the ponds of the traditional polyculture,11.2% higher in organic matter content,but 13.5% and 5.1% lower in TP and TN.The mechanism of generation of the pollutants has been analyzed.