禁渔初期鄱阳湖鱼类时空分布特征

HYDROACOUSTIC SURVEYS ON SPATIAL-TEMPORAL DISTRIBUTION OF FISHES DURING EARLY FISHING BAN PERIOD IN POYANG LAKE

  • 摘要: 研究于2020—2021年使用Simrad EY60鱼探仪对鄱阳湖进行了秋季、春季和冬季共3次的水声学调查, 并同步开展渔获物调查作为补充, 分析鄱阳湖鱼类资源时空分布变化特征。结果表明: 在季节分布上, 鱼类目标强度和密度值都存在显著差异(P<0.05), 在目标强度上表现为冬季(–51.0±14.13) dB>春季(–52.10±4.59) dB>秋季(–52.71±9.95) dB, 在鱼类密度上表现为冬季(54.61 ind./1000 m3)>秋季(46.10 ind./1000 m3)>春季(18.54 ind./1000 m3); 在水平分布上, 鱼类资源空间分布不均且不同湖区间有显著差异(P<0.05), 秋季鱼类主要分布在中部湖区松门山, 冬季鱼类主要分布在北部湖区通江水道; 在垂直分布上, 秋季和冬季均表现为底层>中层>表层, 春季表现为表层>中层>底层。综合来看, 鄱阳湖鱼类时空分布与鱼类的生活习性如产卵、育肥和越冬等因素密切相关。研究结果为从宏观空间尺度分析区域鱼类时空变动特征提供参考, 也为鄱阳湖禁捕效果评估及生物完整性评价提供数据支撑。

     

    Abstract: Poyang Lake is the largest freshwater lake in China, and a typical natural lake in the middle and lower reaches of the Yangtze River. Different habitat season landscapes can meet the needs of fish in different life history stages, so that fish resources show dynamic distribution characteristics. The 10-year fishing ban have been implemented in the Yangtze River basin, including Poyang Lake since Jan 1, 2021, to conserve the aquatic organism of the Yangtze River. In this study, we applied hydroacoustic analysis with Simrad EY60 split-beam echo sounder, to detect the spatial-temporal distribution of fish in Poyang Lake from 2020 to 2021. The results showed that more than half of the fish were 10—30 cm of body length in all three seasons, deduced from the fish target strength (TS) signal. However, the TS varied significantly among seasons (P<0.05), with the highest TS in winter (–51.0±14.13) dB and the lowest (52.71±9.95) dB in autumn. The horizontal distribution of fish density was not homogeneous, and also significantly different among seasons (P<0.01). The maximum density was 440.22, 169.19, and 554.18 ind./1000 m3 in autumn, spring, and winter, respectively. Vertically, the fish density decreased gradually from the bottom to the surface in autumn and winter, while the fish density in the surface and middle layers was higher than that in the bottom in spring. The fish density varied significantly in the same water layer among seasons (P<0.01). This study obtained the spatial and temporal distribution characteristics of fish in Poyang Lake by using hydroacoustic method at the beginning of fishing ban, and provided a reference for the study of fish resource in the region at a macro spatial scale under natural conditions. The results can also support for the evaluation of the fishing ban effect and the evaluation of biological integrity during the ten-year fishing ban in Poyang Lake.

     

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