滤食杂食性鱼类放养对浮游动物群落结构的影响

Effect of filter-feeding omnivorous fish on zooplankton community

滤食杂食性鱼类是我国南方水体中常见鱼类,本文调查了放养滤食杂食性鱼类后浮游动物的丰度和种类组成的变化,以探讨其对浮游动物群落的影响。结果显示,滤食杂食性鱼类放养之后,枝角类模糊秀体溞(Diaphanosoma dubium)、微型裸腹溞(Moina micrura)和桡足类蒙古温剑水蚤(Thermocyclops mongolicus)、南方近镖水蚤(Tropodiaptomus australis)等丰度迅速下降,而轮虫丰度在鱼类放养一周后迅速增加,且保持较高的密度;轮虫优势种也发生了变化,调查前两周主要以臂尾轮虫(Brachionus)为主,两周后以暗小异尾轮虫(Trichocereidae pusilla)、广布多肢轮虫(Polyarthra trigla)和裂痕龟纹轮虫(Anuraeopsisfissa)等个体更小的种类为主。本研究说明,滤食杂食性鱼类能够显著影响浮游动物群落结构,个体较大的种类受到的影响较大,最后导致浮游动物群落的小型化。

Filter-feeding omnivorous fish was the common fish in southem China. In order to evaluate the influence of the fish on zooplankton community, the changes in species composition, abundance of zooplankton community after filter-feeding omnivorous fish stocking were studied in this study. The results showed that after the fish stocking, there was a rapid decrease in abundance of Cladocera （Diaphanosoma dubium and Moina micrura） and Copepoda （Thermocyclops mongolicusand and Tropodiaptomus australis）. The density of Rotifera increased one week after stocking, and then high density was maintained. The dominant species of Rotifers were also changed, with Brachionus dominating in the first two weeks and Trichocereidae pusilla, Polyarthra trigla and Anuraeopsisfissa dominating during the rest of the study period. Our study demonstrated that filter-feeding omnivorous fish can impose a significant impact on zooplankton community, and large-sized zooplankton suffered a more significantly negative effect leading to the dominance of small-sized individuals and species in zooplankton community.