Abstract:
Globally, catadromous freshwater eels of the genus Anguilla are of conservation concern, including critically endangered European eel (Anguilla anguilla). Pumping stations that move river water to a higher elevation severely impact eels during their seaward spawning migration. Fish-friendly pumps can mitigate fish injury and mortality but here we uniquely rethink a fish-friendly pump as a fish passage solution. In this pluriannual study, the seasonal timing of pump operation was misaligned with the typical silver eel migration period. Eels were almost exclusively nocturnal but night-time pumping represented as little as 5.6% a year. Night-time eel approaches were primarily influenced by pump duration and temperature, but did not align with lunar phase, unlike in unregulated rivers. After reaching the pumping station, eel passage was influenced by weedscreen aperture and increased when the aperture was increased. Passive sensor collision suggested non-pump infrastructure could cause injury and mortality to eels. It is therefore recommended pump operation should align with the timing of silver eel migration, weedscreen and pump entrance efficiencies should be maximised, and non-pump infrastructure must have low fish injury risk. Ultimately, considering the entire structure a fish passage solution will help ensure fish-friendly pumps have high conservation value for anguillid eels globally.
摘要:
全球范围内,安圭拉属的重性淡水鳗鱼受到保护关注,包括极度濒危的欧洲鳗鱼(安圭拉anguilla)。将河水移至较高海拔的抽水站在向海产卵的迁徙过程中严重影响鳗鱼。鱼类友好泵可以减轻鱼类伤害和死亡率,但在这里,我们独特地重新思考鱼类友好泵作为鱼类通道解决方案。在这项年度研究中,泵运行的季节性时间与典型的银鳗鱼迁移期不一致。鳗鱼几乎完全是夜间活动,但夜间抽水每年仅占5.6%。夜间鳗鱼进近主要受泵持续时间和温度的影响,但与月相不一致,与无管制的河流不同。到达泵站后,鳗鱼通道受到滤网孔径的影响,并且随着孔径的增加而增加。被动传感器碰撞表明,非泵基础设施可能会导致鳗鱼受伤和死亡。因此,建议泵的运行应与鳗鱼迁移的时间一致,应最大限度地提高杂草屏幕和泵入口的效率,非泵基础设施必须具有较低的鱼类伤害风险。最终,考虑到整个结构,鱼类通道解决方案将有助于确保对鱼类友好的泵对全球鳗鱼具有很高的保护价值。