海河流域大清河水系的鱼类多样性

为了解大清河水系的鱼类种群多样性组成特点，于2018—2019年间对大清河水系进行多次鱼类调查，结合历史文献资料，梳理了大清河水系的鱼类种类共85种，其中自然分布的淡水鱼类共计8目17科59属78种。这些鱼类多为常见种，珍稀濒危物种占比低，可以充分代表海河流域鱼类区系，是大清河鱼类群落组成的重要特点。然而现状调查只能调查到42种，其中尚自然分布于流域的种类则降低到33种，且以小型鱼类、小个体鱼类为主。Margalef丰富度指数、Shannon-Wiener多样性指数、Pielou均匀性指数分别为1.98、1.14、0.81，同海河流域其他水系相比，表明大清河水系鱼类物种多样性一般 较低，且各区域分布较均匀。多角度考察显示，目前流域鱼类区系的完整性已被高度破坏，鱼类多样性呈现出显著的下降趋势。经济发展驱动的用水需求和大清河流域水资源量不足是导致鱼类多样性减少的主要原因，生境变化、水域污染、水工建设、过度捕捞等也是不可忽视的因素。因此保证一定生态流量和一定程度恢复河流连通性、加强水污染治理、开展人工增殖放流、加大禁捕力度等，都可改善流域鱼类多样性现状。

Fish Community Diversity in the Daqing River System of Haihe River Basin

In order to understand the fish species composition of the Daqing River system, several field surveyswere conducted from 2018 to 2019. Based on field surveys data and relevant literatures, the results showed that there were 85 fish found in the Daqing River basin including 78 freshwater species, which belongs to 59 genera, 17 families and 8 orders. High proportion of common fish, low proportion of threatened and endemic species are characters of fish diversity of the Daqing River system, which could well-represent the fish fauna of the Haihe River. However, we only could collected 42 species during surveys. Only 33 of them are naturally distributed in the river. The average value Margalef richness index, Shannon-Wiener diversity index and Pielou evenness index of fish in Daqing River system were 1.98, 1.14 and 0.81 respectively, indicating that the species diversity of the Daqing River system was general and the distribution of each region was relatively uniform. Overall, the integrity of fish fauna has been destroyed. The species diversity is dramatically decreasing. The conflicts between the water demands from economic development and limited water resources are a primary infector causing the collapse of fish species diversity. Additionally, habitat degradation, water pollution, dam construction, and over-exploitation are all factors which should not be ignored. Maintaining a certain ecological discharge, restoring river connectivity, enhancing pollution management, applying the stock enhancement, and forbidding fish capture are effective means to improve the fish diversity.