Author(s): Miao Wu, Ang Chen, Pengyuan Wang, Chen Shen
Linked Author(s): Wu Miao
Keywords: Driving force, Xiaolangdi, water-sediment regulation, the Yellow River, fish habitat
Abstract: This paper presents a detailed study on fish survey and habitat assessment, which focuses on driving force of fish community and fish habitats evolution in the downstream of Xiaolangdi Dam. Firstly, six typical hydrological stations are chosen as fish survey sections and two fish resources reserved sites as important fish habitats. Four times survey has been finished. Secondly, both fish species and their abundance are compared with survey results in the past, and fish habitats parameters in the two important habitats are analyzed. Not only fish community and habitats in the past, but also differences before and after water-sediment regulation are compared. Thirdly, driving forces are analyzed based on hydrological alteration analysis. Five groups of IHA parameters are used to compare different hydrological regimes. Relationship between water-sediment regulation and downstream fish community and habitats are discussed. Finally, driving forces of fish community and habitats evolution are analyzed, and the results reveal that: (1) fish species and resources decrease heavily compared to those in 1980s, flow and sediment significantly decrease in the last sixty years, and flow recovers after Xiaolangdi Dam operation, (2) downstream fishes decrease in water-sediment regulation period which probably affected by the high velocity flow and decreased DO, but fish resources recover in 15~30 days after regulation, (3) hydrological alteration might be the driving force of aquatic ecosystem in the lower Yellow River, habitats do not suit the fishes because the flow and sediment increase, while DO decrease in the regulation period, but it is still under discussion whether fish habitats inundation and erosion which would lead to death of eggs, juvenile fishes and even adult fishes are resulted from water-sediment regulation (4) long-term aquatic monitoring is needed for establishing the relationship between hydrological alteration and fish community and habitats, and more reasonable operation mode should be proposed to consider more on downstream aquatic ecosystem
Year: 2017