文献类型： 外文期刊

作者： Tao JiangPing ¹ ; Gong YuTian ¹ ; Tan XiChang ³ ; Yang Zhi ¹ ; Chang JianBo ¹ ;

作者机构： 1.Minist Water Resources, Inst Hydroecol, Key Lab, Minist Water Resources Ecol Impacts Hydraul Proje, Wuhan 430079, Peoples R China

2.Chinese Acad Sci, Wuhan 430079, Peoples R China

3.Chinese Acad Fishery Sci, Pearl River Fishery Res Inst, Guangzhou 510380, Guangdong, Peoples R China

关键词： fisheries acoustics;geostatistics;fish assemblage;CPUE;impoundment of Three Gorges Reservoir;Yangtze River

期刊名称：SCIENCE CHINA-LIFE SCIENCES （ 影响因子：6.038； 五年影响因子：4.754 ）

ISSN： 1674-7305

年卷期： 2012 年 55 卷 7 期

页码：

收录情况： SCI

摘要： An explicit demonstration of the changes in fish assemblages is required to reveal the influence of damming on fish species. However, information from which to draw general conclusions regarding changes in fish assemblages is insufficient because of the limitations of available approaches. We used a combination of acoustic surveys, gillnet sampling, and geostatistical simulations to document the spatiotemporal variations in the fish assemblages downstream of the Gezhouba Dam, before and after the third impoundment of Three Gorges Reservoir (TGR). To conduct a hydroacoustic identification of individual species, we matched the size distributions of the fishes captured by gillnet with those of the acoustic surveys. An optimum threshold of target strength of -50 dB re 1 m(2) was defined, and acoustic surveys were purposefully extended to the selected fish assemblages (i.e., endemic Coreius species) that was acquired by the size and species selectivity of the gillnet sampling. The relative proportion of fish species in acoustic surveys was allocated based on the composition (%) of the harvest in the gillnet surveys. Geostatistical simulations were likewise used to generate spatial patterns of fish distribution, and to determine the absolute abundance of the selected fish assemblages. We observed both the species composition and the spatial distribution of the selected fish assemblages changed significantly after implementation of new flow regulation in the TGR, wherein an immediate sharp population decline in the Coreius occurred. Our results strongly suggested that the new flow regulation in the TGR impoundment adversely affected downstream fish species, particularly the endemic Coreius species. To determine the factors responsible for the decline, we associated the variation in the fish assemblage patterns with changes in the environment and determined that substrate erosion resulting from trapping practices in the TGR likely played a key role.