通江湖泊石臼湖鱼类群落结构现状及其季节变化

石臼湖是长江下游唯一的自然通江湖泊, 为掌握其鱼类资源状况, 本研究于 2017 年 1 月至 2018 年 3 月采用多目刺网和定制串联笼壶采集石臼湖渔获物, 分析了石臼湖鱼类群落结构及其季节变化。结果显示, 共采集到鱼类 36 种, 隶属于 6 目 7 科 28 属, 其中鲤科鱼类最多, 占总物种数的 69.44%; 鱼类物种组成以定居性、杂食性、中上层鱼类为主, 小型鱼类达 25 种, 占总物种数的 69.44%。似鱎(Toxabramis swinhonis)、刀鲚(Coilia nasus)和鲫 (Carassius auratus)为石臼湖鱼类全年优势种; 除全年优势种外, 季节特有优势种有春季的麦穗鱼(Pseudorasbora parva)、夏季的翘嘴鲌(Culter alburnus)和?(Hemiculter leucisculus)、秋季的似鳊(Pseudobrama simoni)、冬季的贝氏?(Hemiculter bleekeri)。鱼类相对密度、相对生物量有较大的季节变化, 但其变化趋势一致, 均按照冬季、春季、 秋季、夏季由高到低排列。Margalef 丰富度指数 R 的变动范围为 2.28~3.17, 基于个体数量的 Shannon-Wiener 多样性指数 H_N′ 、Pielou 均匀度指数 J_N′ 变动范围分别为 1.24~2.14、0.14~0.34, 基于生物量的 Shannon-Wiener 多样性指数 H_W′ 、Pielou 均匀度指数 J_W′ 变动范围分别为 1.64~2.51、0.21~0.49, 各指数除 H_W′ 在夏秋季间差异不显著外, 其余指数夏季都显著高于其他季节(P<0.05)。研究结果表明, 石臼湖鱼类种类较少, 多样性偏低。本研究补充了通江湖泊鱼类群落研究的基础资料, 对长江中下游鱼类多样性保护具有一定的意义。

Current status and seasonal variations in fish community structure in the Shijiu Lake, the Yangtze River-connected lake

Shijiu Lake is the only river-connected lake in the lower reaches of the Yangtze river. To determine the status of its fish resources, this study used multi-mesh gill nets and customized series cage pot to collect fish in the Shijiu Lake in the season from January 2017 to March 2018, and analyzed the fish community structure and seasonal changes in the Shijiu Lake. Our subsequent results showed that a total of 36 species of fish were collected, belonging to 28 genus, 7 families and 6 orders, among which Cyprinidae was the most common, accounting for 69.4% of the total species. The fish species were primarily sedentary, omnivorous, and pelagic fish with 25 small fish accounting for 69.44% of the total species. Toxabramis swinhonis, Coilia nasus, and Carassius auratus were the dominant species of the Shijiu Lake throughout the year. In addition to the dominant species throughout the year, the seasonal unique dominant species are Pseudorasbora parva in spring, Culter alburnus and Hemiculter leucisculus in summer, Pseudobrama simoni in autumn and Hemiculter bleekeri in winter. The relative density and biomass of fish showed marked seasonal variation, but the variation trend was the same: winter > spring > autumn > summer. The Margalef richness index R ranged from 2.28 to 3.17. The variation range of Shannon-Wiener diversity index H''_N and Pielou evenness index J''_N based on individual number was 1.24-2.14 and 0.14-0.34, respectively. The variation range of Shannon-Wiener diversity index H''_W and Pielou evenness index J''_W based on biomass was 1.64-2.51 and 0.21-0.49, respectively. All indexes were significantly higher in summer than those in other seasons, except H''_W in summer and autumn (P<0.05). The results showed that the fish species diversity of the Shijiu Lake were low. This study complements the basic data of fish community research in the Yangtze River-connected lake, and has a certain significance for the protection of fish diversity in the middle and lower reaches of the Yangtze River.