长江下游近岸渔业群落多样性时空特征

2001至2008年对安庆、常熟和崇明3个断面的插网渔获物进行了连续调查,以此研究长江下游近岸渔业群落多样性的时空特征。研究期内共计采集鱼类80种,甲壳类14种,水母类1种,分别隶属于15目34科74属。安庆共记录52个物种,隶属于7目14科39属,常熟共记录55个物种,隶属于12目23科46属,崇明共记录31个物种,隶属于9目18科28属。安庆和常熟淡水物种比例分别为92.31%和70.91%,崇明咸水物种比例为90.32%。各断面均为底栖物种占优势,比例为38.18%~64.52%;肉食性和杂食性物种所占比例接近,合并为88.46%~100%。长江下游水域渔业群落多样性表现出逐渐由淡水型向咸水型过渡的空间特征,季节特征则表现为夏季和秋季物种数较多,春秋两季的渔获规格及多样性指数较大。年间变动趋势表明实施春季禁渔后安庆和常熟断面群落多样性水平显著提升并趋于稳定,渔获量大幅增加,崇明断面各项指标波动剧烈,尚无好转迹象。

Temporal and spatial diversity characteristics of nearshore fishery community in the lower reaches of Yangtze River

Based on the sustained investigation on sampling catch in stow net of Anqing, Changshu and Chongming sections, studies on temporal and spatial diversity characteristics of nearshore fishery community in the lower reaches of Yangtze River were carried out during 2001-2008.In this period, eighty fish species, fourteen crustacean species and one jellyfish species, belonging to 15 orders, 34 families and 74 genera, were collected.A total of 52 species belonging to 7 orders, 14 families and 39 genera were recorded in Anqing section, 55 species belonging to 12 orders, 23 families and 46 genera in Changshu section and 31 species belonging to 9 orders, 18 families and 28 genera in Chongming section.Proportion of freshwater species in community of Anqing and Changshu were 92.31% and 70.91% respectively, while marine water species proportion of Chongming was 90.32%.Fishery communities in three sections were all dominated by benthic species, which occupied 42.31-54.84% of aforesaid communities, and proportion of carnivorous species was close to that of omnivorous species, with the combination ranged from 88.46% to 100%.The significant difference in water ecological environment determined the spatial diversity characteristic of fishery community in the lower reaches of the Yangtze River, which showed a gradual transition from freshwater community to marine water community.On the other hand, it showed that species collected in summer and autumn were more than those in spring and winter, at the same time bigger size and diversity indexes could also be observed in spring and autumn.Yearly fluctuation of main indexes indicated that after the Spring no-fishing, diversity level of fishery communities of Anqing and Changshu rose significantly with a smooth trend.But in Chongming section, the same indexes fluctuated in a wide range, without uptrend.