鱼类养殖对水体磷酸盐的影响：源、汇的半现场实验例证

设置4个温度水平（16℃,20℃,23℃和26℃）和3个投喂水平（1%,2%和饱食水平）,在类养殖场条件下饲喂许氏平鲉,研究其对水体磷酸盐浓度的影响.结果表明,在所有温度、投喂水平下,水体的磷酸盐浓度均有升、降.从物质平衡角度看,养殖鱼类是水体磷酸盐的源,但又不是单纯的源,因鱼粪和残饵等微粒的吸附作用,养殖鱼类有可能成为水体磷酸盐的汇。因此在评价鱼类养殖的环境容量时,慎用活性磷酸盐磷这个指标。此外,进行鱼类养殖环境影响评价时,应加强颗粒物的监测;为降低水体的磷负荷,磷酸盐和水体颗粒物质均应是生态调控的对象。

Effects of Pisciculture on Phosphate Concentration of Water Body:One Source or One Sink, a Semi-Field Experiment Example

Black stock fish Sebastodes fuscescens（Houttuyn）was cultured under farm-like conditions.They were fed at 1%,2% and satiation ration levels.There were four temperature levels,which were 16℃,20℃,23℃ and 26℃,respectively.In despite of temperature and ration levels,phosphate concentration of water body not only increased but also decreased.Thus,cultured fish was the source of phosphate of water body but not a sheer one.It functioned as one phosphate sink because of adsorption effect of suspended particulate matters caused by pisciculture just as feed remains,fish feces and so on.Hence,it should be discreet to use phosphate as one criterion for determining the carrying capacity of pisciculture zones.Furthermore,investigations on suspended particulate matters and phosphorus content of sediment or suspended particulate matters should be taken as studying the impacts of this industry.In order to reduce phosphorus load,both phosphate concentration and particulate matters of water body should be controlled.