不同鱼类养殖方式对长江中游湖泊浮游植物群落的影响及其季节动态

湖泊鱼类养殖是非常重要的一种水产养殖方式，然而不同鱼类养殖和管理方式对湖泊浮游植物群落的影响及其季节动态尚不明确。2016年3月~2017年1月按季度调研了长江中游9个湖泊的浮游植物，所研究湖泊包括以下4组：水库极低密度放养组（SR组）、禁养组（SN组）、低密度养殖组（SL组）和高密度养殖组（SH组）。研究表明：4组湖泊共鉴定出浮游植物8门110属，以绿藻、硅藻和蓝藻为主。水库组优势种季节演替明显，其余3组均存在比较稳定的优势种，其中禁养组与高密度养殖组为平裂藻，低密度养殖组为假鱼腥藻。4组湖泊浮游植物丰度的季节变化规律不同，依赖于蓝藻优势度的变化。根据浮游植物多样性指数判断，4组湖泊水体污染状态（即营养状态）存在季节差异，Shannon Wiener指数与Pielou指数对水体污染状态的评价结果较为一致。对4组湖泊四季的浮游植物的数量进行了层序聚类分析与非度量多维尺度分析（NMDS），结果显示水库组单独为一类；禁养组与高密度养殖组除了夏季外，其余季节均为一类。不同鱼类养殖方式对湖泊浮游植物群落的结构及季节动态产生了一定的影响，然而短期的禁养并没有明显改变湖泊浮游植物群落。

Effects of Fish Culture on Phytoplankton Communities and Seasonal Dynamcis in Lakes Along the Middle Yangtze River

Fish culture in lakes is a very common and important aquaculture in China but few study reported comprehensive ecological impacts of different fish culture types on lakes. We assessed phytoplankton communities from March, 2016 to January, 2017 seasonally in 9 lakes, which included four groups: reservoir group (group SR), non aquaculture group (group SN), low stocking aquaculture group (group SL) and high stocking aquaculture group (group SH), along the middle Yangtze River. A total of 110 phytoplankton genera belonging to 8 phyla were collected, among which were mainly Chlorophyta, Bacillariophyta and Cyanophyta. The seasonal succession of major dominant species in the reservoir group was remarkable, while there were stable dominant genera in the non aquaculture (Merismopedia), low stocking aquaculture (Pseudanabaena) and high stocking aquaculture (Merismopedia) groups. The seasonal patterns of phytoplankton abundance in the four lake groups were different and depended on the dominance of cyanobacteria. According to the phytoplankton diversity index, water pollution (nutrient) status of the four lake groups showed seasonal differences, and the evaluation results of the Shannon Wiener index were consistent with those of the Pielou index. Hierarchical cluster analysis and non metric multi dimensional scaling (NMDS) showed that lakes in the reservoir group were in the same category in all seasons, and lakes in the non aquaculture and high stocking groups were in the same category in all seasons except summer. The current study indicated that fish culture had some impacts on phytoplankton communities, but banning from aquaculture in a short time did not significantly change them in lakes.