滤食性鱼类鲢放养量对淀山湖水质影响的围隔试验

为研究非经典生物操纵技术控制淀山湖水体富营养化时最佳的鲢(Hypophthalmichthys molitrix)放养量,于2009年夏季在淀山湖开展原位围隔试验。鲢放养密度设0、40、80、120 g/m3四个水平,每组设2个重复。每隔10天采样一次,分析水质。实验结果表明:(1)鲢密度为40 g/m3时可一定程度降低淀山湖围隔水体中有机物质(以高锰酸盐指数为代表);80 g/m3时对总氮的降低以及水体透明度的提高最有效;各放养密度对总磷的影响均不明显。(2)对于淀山湖水体而言,鲢的放养可以净化水体,提高生态系统稳定性;当放养密度为80 g/m3时,效果最好。

Situ enclosure experiment of silver carp effecting on water quality in Dianshan Lake

Basing on non-classical theory of biological control,an in situ enclosure experiment was done to study the silver carp effects on water quality during summer in 2009.There were four stocking levels:0,40,80,120 g/m3,with two duplicated.Samples were taken with an interval of 10 days to determinate chemical measurements.The results show ed that:(1) 40 g /m3 density of silver carp can reduce the content of the organic material(CODMn) to a certain extent;80 g/m3 density is the most effective for the decrease of total nitrogen and the improvement of water transparency;The total phosphorus was not obviously.(2) For the waterbody of Dianshan Lake,silver carps stocking can purify water,improve the ecological system stability and the effect is the best when density for 80 g/m3.