青鱼-鲢、鳙生态池塘浮游生物群落结构特征及其与环境因子的关系

Relationship between Plankton Community Structure and Environmental Factors in Ecological Culture Ponds of Black Carp Mylopharyngodon piceus-Silver Carp Hypophthalmichthys molitrix and Bighead Carp Aristichthys nobilis

为探究青鱼-鲢、鳙生态养殖池塘中浮游生物群落结构特征及其与环境因子的关系,于2015年4-10月对3口青鱼养殖池塘的浮游生物及水质理化性质进行监测。结果显示,在青鱼-鲢、鳙生态养殖池塘中共检出浮游植物112种,其中绿藻门(47种)、裸藻门(30种)和硅藻门(17种)为优势门类,优势种有扭曲小环藻、普通小球藻和被甲栅藻,浮游植物平均密度和生物量分别为3.24×10^(7)个/L和32.10mg/L。共检出浮游动物96种,其中原生动物42种、轮虫40种、枝角类9种、桡足类5种,优势种有裂痕龟纹轮虫、针簇多肢轮虫和暗小异尾轮虫等,浮游动物平均密度和生物量分别为6.08×10^(4)个/L和5.20mg/L。不同月份浮游植物和浮游动物的多样性指数中,香农-维纳多样性指数分别为1.8~2.5和2.9~4.5、物种丰富度指数分别为2.5~4.9和1.2~4.1、物种均匀度指数分别为0.51~0.69和1.5~2.8。此外,通过Pearson相关性分析和冗余分析对浮游生物群落与水体理化因子之间的关系进行分析,影响青鱼-鲢、鳙生态养殖池塘中浮游生物群落结构的主要环境因子为pH、水温、透明度和溶解氧。因此,在实际生产中可通过调控水质来控制养殖水体中浮游生物群落结构的组成和数量。同时,在高温缺氧的天气应加强水质管理。

In order to study the relationship between plankton community structure and environmental factors in the ecological culture ponds of black carp Mylopharyngodon piceus-silver carp Hypophthalmichthys molitrix and bighead carp Aristichthys nobilis from April to October 2015,the plankton and physicochemical properties of water quality were monitored in three black carp culture ponds.The results showed that a total of 112 species of phytoplankton were detected in ecological culture ponds,including Chlorophyta(47),Euglenophyta(30)and Bacillariophyta(17)being the dominant taxonomy.The dominant species were Cyclotella comta,Chlorella vulgaris and Scenedesmus armatus.The average density and biomass of phytoplankton were 3.24×10^(7)ind./L and 32.10 mg/L.A total of 96 species of zooplankton were detected,including 42 protozoa,40 rotifers,9 branchopods and 5 copepods.The dominant species were Anuraeopsis fissa,Polyarthra trigla Ehrenberg and Trichocerca pusilla,with average zooplankton density and biomass of 6.08×10^(4)ind./L and 5.20 mg/L.The diversity index of phytoplankton and zooplankton in different months were Shannon-Wiener′s diversity index(1.8—2.5 and 2.9—4.5),species richness index(2.5—4.9 and 1.2—4.1),and species evenness index(0.51—0.69 and 1.5—2.8).In addition,the relationship between plankton community and physicochemical factors in water was discussed through Pearson correlation analysis and redundancy analysis(RDA).It was found that pH,water temperature(T),transparency(SD)and dissolved oxygen(DO)were the main environmental factors affecting the plankton community structure in the ecological culture ponds of black carp,silver carp and bighead carp.Therefore,in actual production,the composition and quantity of plankton community structure in aquaculture water can be controlled by regulating water quality,so as to improve aquaculture yield.Meanwhile,water quality management should be strengthened in the weather of high temperature and hypoxia.