三峡水库万州大周库湾网箱养鱼对水环境的影响

2005年6月至2006年4月,对三峡水库万州大周库湾投饵式网箱养鱼基地的水质和底泥进行了调查与分析.结果表明:万州大周投饵式网箱养殖对水温、DO、透明度、pH及电导率的影响都不显著.网箱养殖区水温、DO略低于网箱上游和网箱下游.氨氮、硝酸盐、亚硝酸盐、总氮、总磷及正磷酸盐的含量趋势为网箱区最高,其次网箱下游,网箱上游最低,ANOVA分析结果显示差异不显著(p0.05).无机氮的主要形态以硝态氮为主,其次是氨氮,亚硝态氮最少.以总氮和总磷作为氮、磷阈值来分析,网箱上游水质已达到富营养化水平,按地表水环境质量标准(GB3838-2002)评价,网箱上游为Ⅲ类、劣Ⅲ类水质,网箱区为劣Ⅳ类,网箱下游为Ⅳ类水,网箱养殖加重了该水域水质的富营养化.网箱养殖使底泥中氮、磷、硫化物、有机质大量富集.

Effect of Fish Culture in Net-Cages on Water Environment in Dazhou Bay in the Three Gorges Reservoir, in Wanzhou, Chongqing

Water quality and bed mud in Dazhou Bay in Wanzhou,Chongqing were surveyed and analyzed from June,2005 to April,2006.The results showed that net-cage culture had no significant effects on the temperature,dissolved oxygen(DO),transparency,pH and conductivity of the water.The temperature and dissolved oxygen concentrations of the water in cage-culture area were slightly lower than in the control area.The contents of ammonia nitrogen,nitrate nitrogen,nitrite nitrogen,total nitrogen,total phosphorus and orthoph...