太湖新银鱼种群摄食对小江浮游动物群落结构的影响OA北大核心CSTPCD

In this study,we explored the effect of Neosalanx taihuensis feeding on zooplankton commu-nity structure in Xiaojiang River,a typical tributary of Three Gorges Reservoir.Our aim was to provide a theoretical basis for fishery management and ecological restoration of Xiaojiang River.From January to December 2019,N.taihuensis and zooplankton were collected monthly at three sections in the upper,mid-dle and lower Xiaojiang River,and the stomach contents of N.taihuensis,and zooplankton community structure were analyzed.Results show that:(1)During the investigation,a total of 334 N.taihuensis speci-mens,and their stomach contents,were sampled.The primary feeding organisms for N.taihuensis were Copepods,followed by Cladocerans and Rotifers,with relative importance indices of 79.97％18.86％and 0.001％,respectively.(2)From March to June,the biomass of N.taihuensis increased rapidly,while the zooplankton community tended toward miniaturization.Zooplankton biomass decreased sharply from 28.93 mg/L to 1.13 mg/L while the density increased from 21 173.39 ind/L to 26 808.23 ind/L.When the fishing ban period ended in July,the biomass of N.taihuensis began to decline sharply while the density and biomass of Copepods and Cladocerans increased rapidly,peaking at 151.98 ind/L and 3.39 mg/L in August.(3)During the rapid growth period of N.taihuensis in May and June,the biomass proportions of Cladocerans and Copepods was significantly lower(17％-58％)than at other times(P＜0.05).The strong correlation between N.taihuensis biomass and zooplankton biomass,and the results of stomach content analysis,clearly show that N.taihuensis foraging affects zooplankton community structure.The top-down effect of N.taihuensis feeding explains the decline of zooplankton biomass and the miniaturization of zooplankton community in the Xiaojiang River.Clarifying the extent and timing of the dynamic rela-tionship between N.taihuensis growth and zooplankton community structure provides a theoretical basis that supports coordinated efforts to control algal blooms and manage aquatic ecology in Xiaojiang River.