European eel, Anguilla anguilla L., migrating to the sea encounter many man-made structures that can hamper and delay migration or induce mortality. Studying smallscale behavioural movements in front of these man-made structures could provide insight in further mitigating adverse effects. The behaviour of eel approaching a trash rack in front of a large pumping station was investigated using a dual-frequency identification sonar (DIDSON). Eels approaching the trash rack swam through the rack (40.5%) but also showed turning behaviour at (44.7%) or in front of the rack (14.7%). Eels approaching the rack had varying body positions, predominantly head or tail first, but also curled up into a ball or drifted sideways. After turning in front or at the trash rack, eels showed upstream and downwards swimming towards the canal bottom. The results suggest a stepwise response to potential cues, when firstly the body position is changed in such a way that secondly, later on, enhances eventual fast upstream escapement when perceived necessary. Implications for management of these behavioural observations are discussed.

中文翻译：

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使用声学相机 (DIDSON) 接近带有拦污栅的大型泵站的鳗鱼 (Anguilla anguilla) 的行为反应

欧洲鳗鲡（Anguilla anguilla L.）在迁徙到大海时遇到了许多可能阻碍和延迟迁徙或导致死亡的人造结构。研究这些人造结构前的小规模行为运动可以为进一步减轻不利影响提供见解。使用双频识别声纳 (DIDSON) 研究了鳗鱼接近大型泵站前拦污栅的行为。接近垃圾架的鳗鱼游过架子 (40.5%)，但也在架子 (44.7%) 或架子前面 (14.7%) 表现出转弯行为。接近架子的鳗鱼有不同的身体姿势，主要是头或尾在前，但也有蜷缩成球状或侧身飘​​动的情况。在前面或在垃圾架处转弯后，鳗鱼呈上下游向运河底部游动的迹象。结果表明对潜在线索的逐步响应，当首先身体位置以这样的方式改变时，其次，随后在认为必要时增强最终的快速上游擒纵机构。讨论了对这些行为观察的管理的影响。