Hydropower plants (HPPs) are a source of “green” energy but also a threat to migrating fish such as the European eel (Anguilla anguilla) owing to the disruption of river connectivity and the obstruction of downstream migration. The impact of HPP are well-documented in terms of fish survival and damages but there is no available information concerning the condition of surviving and unharmed fish. The aim of this study is to assess the impact of the passage through HPP on the survival, the physiological and health status of adult eels. Two trials were carried with variants of the Kaplan turbine - one of the most common types in Europe. After a deliberate passage through the turbines, we studied direct mortality, external and internal damages, stress and immune biomarkers such as plasma cortisol and glucose levels, alternative complement (ACH50), lysozyme and peroxidase activities, and total immunoglobulin (Ig) content. Our results showed a lower survival and a higher external and internal damages rates in the HPP groups. Glucose levels, ACH50, lysozyme and peroxidase activities and TIgc were also affected by the passage depending on HPP characteristics. Those findings suggest a greater energy expenditure and a disruption in innate immunity due to this passage. HPPs can not only have an impact in terms of direct mortality and injuries but also affect the physiological and health condition of the surviving eels. This impact may explain the delayed mortality observed in telemetric studies and the passage through many HPPs may compromise the ability of adult eels to migrate successfully to the ocean.

水力发电厂 (HPP) 是“绿色”能源的来源，但也威胁着洄游鱼类，例如欧洲鳗（安圭拉安圭拉) 由于河流连通性中断和下游迁移受阻。HPP 的影响在鱼类存活和损害方面已有详细记录，但没有关于存活和未受伤害的鱼类状况的可用信息。本研究的目的是评估通过 HPP 对成年鳗鱼的存活、生理和健康状况的影响。使用 Kaplan 涡轮机的变体进行了两次试验 - 这是欧洲最常见的类型之一。在有意通过涡轮机后，我们研究了直接死亡率、外部和内部损伤、压力和免疫生物标志物，例如血浆皮质醇和葡萄糖水平、替代补体 (ACH50)、溶菌酶和过氧化物酶活性以及总免疫球蛋白 (Ig) 含量。我们的结果显示 HPP 组的存活率较低，外部和内部损伤率较高。葡萄糖水平、ACH50、溶菌酶和过氧化物酶活性以及 TIgc 也受传代的影响，具体取决于 HPP 特征。这些发现表明，由于这一通道，能量消耗更大，先天免疫受到破坏。HPPs 不仅可以对直接死亡和伤害产生影响，还可以影响幸存鳗鱼的生理和健康状况。这种影响可以解释遥测研究中观察到的延迟死亡率，并且通过许多 HPP 可能会损害成年鳗鱼成功迁移到海洋的能力。溶菌酶和过氧化物酶活性以及 TIgc 也受传代的影响，这取决于 HPP 的特征。这些发现表明，由于这一通道，能量消耗更大，先天免疫受到破坏。HPPs 不仅可以对直接死亡和伤害产生影响，还可以影响幸存鳗鱼的生理和健康状况。这种影响可以解释遥测研究中观察到的延迟死亡率，并且通过许多 HPP 可能会损害成年鳗鱼成功迁移到海洋的能力。溶菌酶和过氧化物酶活性以及 TIgc 也受传代的影响，这取决于 HPP 的特征。这些发现表明，由于这一通道，能量消耗更大，先天免疫受到破坏。HPPs 不仅可以对直接死亡和伤害产生影响，还可以影响幸存鳗鱼的生理和健康状况。这种影响可以解释遥测研究中观察到的延迟死亡率，并且通过许多 HPP 可能会损害成年鳗鱼成功迁移到海洋的能力。