Response of seaward migrating European eel (Anguilla anguilla) to manipulated flow fields

Anthropogenic structures (e.g. weirs and dams) fragment river networks and restrict the movement of migratory fish. Poor understanding of behavioural response to hydrodynamic cues at structures currently limits the development of effective barrier mitigation measures. This study aimed to assess the effect of flow constriction and associated flow patterns on eel behaviour during downstream migration. In a field experiment, we tracked the movements of 40 tagged adult European eels (Anguilla anguilla) through the forebay of a redundant hydropower intake under two manipulated hydrodynamic treatments. Interrogation of fish trajectories in relation to measured and modelled water velocities provided new insights into behaviour, fundamental for developing passage technologies for this endangered species. Eels rarely followed direct routes through the site. Initially, fish aligned with streamlines near the channel banks and approached the intake semi-passively. A switch to more energetically cos...人为构筑物（anthropogenic structures，诸如堰坝（weirs）与水坝（dams））会割裂河网，制约洄游鱼类的活动。目前学界对鱼类在构筑物处针对水动力信号（hydrodynamic cues）的行为响应认知不足，这限制了高效拦阻屏障缓解措施的研发。本研究旨在探究水流收缩及其伴生流态对鳗鱼下游洄游阶段行为的影响。在本次野外试验中，我们对40尾佩戴追踪标签的成年欧洲鳗鲡（Anguilla anguilla）的活动轨迹进行了追踪，试验设置两组可控水动力工况，观测其在废弃水电站取水口前池内的活动过程。通过解析鱼类活动轨迹与实测、模拟水流流速的关联关系，本研究为该濒危物种的过鱼技术研发提供了至关重要的行为学依据。鳗鱼极少选取直达路径通过该试验区域。初始阶段，鱼类会沿河道岸线附近的水流流线运动，并以半被动的方式趋近取水口。随后，鱼类转而采取更具能量代价的（cos...）