太湖禁捕当年鱼类群落结构及环境驱动因子

Characteristics of fish community structure and environmental driving factors in Taihu Lake during the first year of fishing ban

太湖自2020年10月1日起实施禁捕。2020年四季对太湖全湖鱼类群落进行调查。共采集到鱼类42种,隶属于6目7科33属。相对重要性指数较大的有湖鲚、似鱎、鲢、鳙、陈氏短吻银鱼,其中,湖鲚数量占总渔获物数量的85.1%。根据太湖蓝藻水华及水草分布特征,将太湖分为北部湖区、湖心区以及东部湖区3个湖区。不同湖区间单位努力捕捞渔获量(CPUE)无显著性差异,但东部湖区的Shannon多样性指数和Pielou均匀度指数显著高于其他2个湖区。各季节间的CPUE、Shannon多样性指数、Pielou均匀度指数差异显著。秋季的CPUE最低,秋、冬季各多样性指数均高于春、夏季。电导率、水深、氯化物、透明度是影响鱼类季节差异的主要因子,而电导率、溶解氧、总碱度和透明度是影响鱼类空间差异的主要因子。本研究可作为太湖禁捕鱼类群落结构研究的前期基础数据。

Taihu Lake has officially implemented the full fishing ban policy since October 1,2020.We investigated fish community of Taihu Lake in the four seasons of 2020.A total of 42 fish species were collected,belonging to 6 orders,7 families,and 33 genera.The first five dominant species ranked by the index of relative importance were Coilia nasus,Toxabramis swinhonis,Hypophthalmichthys molitrix,Hypophthalmichthys nobilis,and Sialangichthys tangkahkei.The number of C.nasus accounted for 85.1%of the total number of catches.According to the distributional characteristics of cyanobacterial blooms and aquatic plants,Taihu Lake could be divided into the northern,central,and eastern regions.There was no significant difference in catch per unit effort(CPUE)among different lake regions,but Shannon diversity index and Pielou evenness index in the eastern region was greater than in the other two regions.The CPUE,Shannon diversity index,and Pielou evenness index were significantly different among the four seasons,with the lowest CPUE in autumn and higher diversity in autumn and winter than in spring and summer.Electrical conductivity,water depth,chloride,and transparency were the main environmental factors driving the seasonal variations of fish community in Taihu Lake,while electrical conductivity,dissolved oxygen,total alkalinity,and transparency were key variables driving the spatial patterns.The results could be used as the baseline data for fish community studies in Taihu Lake after the fishing ban.