不同体型大小的鲢对富营养化水体中浮游植物的影响  

Effects of different sizes of silver carp(Hypophthalmichthys molitrix)on phytoplankton assemblage in eutrophic water body

作　　者：靳晓彤 唐雅丽 郭佳 林秋奇[1] JIN Xiaotong;TANG Yali;GUO Jia;LIN Qiuqi(Institute of Hydrobiology,Jinan University,Guangzhou 510632,China)

机构地区：[1]暨南大学水生生物研究中心,广州510632

出　　处：《生态科学》2023年第3期98-105,共8页Ecological Science

基　　金：国家自然科学基金面上项目(32071566)。

摘　　要：浮游植物生物量及群落结构的变化是水体富营养程度的重要表征。鲢是典型的滤食性鱼类,不同大小的鲢会因鳃耙间距的不同对浮游植物进行选择性滤食。为研究不同体型大小的鲢对富营养化水体中浮游植物的影响,于2016年秋季在广东省流溪河水库进行了模拟富营养化条件的室外围隔(体积约为85 m^(3))实验,设置了三个实验组:无鱼对照组、大白鲢组(625.00±25.00)g·ind^(–1)和小白鲢组(10.10±0.50)g·ind^(–1),每组3个重复,以7 g·m^(–3)的密度放养鲢2周后,分别采集浮游植物样品。研究结果显示,实验结束时有鱼组浮游植物生物量均显著低于对照组,其中小白鲢组浮游植物的生物量显著低于大白鲢组,且主要差距为20μm以下的浮游植物。同时,小白鲢组、大白鲢组和对照组的浮游植物群落结构差异显著,冗余分析(RDA)显示微囊藻和隐藻是造成大白鲢组与小白鲢组群落差异的关键藻属。研究发现小白鲢对浮游植物,尤其是微型浮游植物(<20μm)的控制效果比大白鲢更好。此结果对水体管理具有一定的参考意义。Phytoplankton biomass accumulation and its community structure variations are important indicators of eutrophication process.As a typical filter-feeding fish,silver carps with morphologically diverse gill raker systems can filter the phytoplankton selectively,due to their different inter-gill raker spaces at different ages.This experiment was to examine the effects of silver carp of different body sizes on phytoplankton assemblage in eutrophic water.It was hypothesized that small silver carp with smaller inter-gill raker spaces might performance better in the control of picophytoplankton than big silver carp,due to their ability of filtering smaller particles.To test the hypothesis,in the autumn of 2016,an outdoor enclosure experiment was performed in Liuxihe Reservoir,Guangdong Province and each enclosure had a water volume of 85 m3.Nutrients were added in the enclosure one week in advance to simulate eutrophication conditions and nine large enclosures were set,among which three were set for control(no fish),three for big silver carp(625.00±25.00)g·ind^(–1)and the rest for small silver carp(10.10±0.50)g·ind^(–1).Phytoplankton samples were collected after the silver carp were raised at 7 g·m^(–3)for two weeks.Results showed that the phytoplankton biomass of treated groups was significantly lower than that of the control,and the phytoplankton biomass of the small silver carp group was significantly lower than that of the big silver carp group,especially for nanophytoplankton(<20μm)(all P<0.05).Meanwhile,phytoplankton community structure varied significantly among all treatments.RDA showed genus Microcystis and Cryptomonas mainly contributed to phytoplankton community variations between two differently treated groups.In conclusion,silver carp has the potential to control phytoplankton biomass in aquatic ecosystem.What’s more,small silver carp with smaller inter-gill raker spaces may performance better in the control of nanophytoplankton than big silver carp.Our results may give hints at aquatic manage

关 键 词：鲢 体型大小 浮游植物 富营养化 围隔实验 

分 类 号：Q178.1[生物学—水生生物学]