水源治理中鱼类的摄食选择性对其生物操纵作用的影响

针对常规的水处理工艺难以有效地去除水源水中孳生的水蚤类浮游动物的问题,提出利用鱼类的生物操纵作用来抑制水源中水蚤类浮游动物的孳生,实施以水体治理为目的的鱼类放养.微型生态系统的实验结果表明,鱼类的摄食选择性对其生物操纵作用具有重要的影响.在30 g/m3水体的放养密度下,滤食性鲢、鳙鱼可以有效地抑制水体中水蚤类浮游动物的孳生,并通过影响水体中营养物质水平和生物群落结构对水质的恢复也十分有效;草食性草鱼和杂食性鲤鱼在水蚤的生物抑制和促进水质恢复方面没有明显的生物操纵作用.

Effect of food habits of some fishes on the biomanipulation in drinking water source management

Cyclops of zooplankton propagated excessively in a eutrophic body of water and,due to its stronger resistance to oxidation,could not be effectively inactivated using a conventional disinfection process such as chlorination.Adult Cyclops give consumers an unsanitary sense and might become a disease transmission medium as the host of a pathogenic parasite to threaten human health.An ecological project called fish biomanipulation,rather than the conventional fishery culture technique,was put forward for the excess propagation control of Cyclops in order to ensure drinking water security.The control effects on Cyclops of four species of fish were investigated experimentally at a stocking density of 30 g per cubic meter of water.The experimental results showed that the food habits of the fish had significant influence on the biological control of Cyclops.The propagation of Cyclops was controlled effectively and the water quality was also improved simultaneously by stocking the filter-feeding fishes,such as silver carp and bighead carp.When stocking the filter-feeding fishes,the total nitrogen and total phosphorus were decreased to a certain extent and the biomass of phytoplankton,especially blue and green algae,were controlled at a lower level whereas,herbivorous Ctenopharyngodon idellus and omnivorous Cyprinus carpio had no obvious biological effects on controlling the growth of Cyclops and restoring water quality.