Behaviour and passage of European silver eels (Anguilla anguilla) at a small hydropower plant during their downstream migration Comportement et passage de l’anguille argentée (Anguilla anguilla) au niveau d’une petite centrale hydroélectrique lors de sa migration de dévalaison

• Published in: Knowledge and Management of Aquatic Ecosystems
• Main Authors: De-Oliveira E., Gomes P., Subra S., Larinier M., Travade F.
• Format: Article in Journal/Newspaper
• Language: English
• Published: EDP Sciences 2010
• Subjects: silver eel; downstream migration; behaviour; hydroelectric plant; trashracks; radio-tracking; anguille argentée; migration de dévalaison; comportement; centrale hydroélectrique; grilles; radio-télémétrie; Aquaculture. Fisheries. Angling; SH1-691; Anguilla anguilla
• Online Access: https://doi.org/10.1051/kmae/2010022; https://doaj.org/article/3f70e23524ab4a27a2da753e13b35e1e

Between 2004 and 2007, 116 downstream migrant silver eels (Anguilla anguilla) were monitored at a hydropower plant on the Gave de Pau river in South-West France using radio and PIT telemetry. The objectives of the study were: (i) to determine the environmental conditions when eels arrived and passed the facility; (ii) to determine the rate of eel escapement (passage other than via the turbines); (iii) to describe the behaviour of eels faced with the intake structure and the permeability of the intake trashracks for the different sizes of eel; and (iv) to determine whether surface bypasses originally designed for salmon could be effective for eels. Five types of behaviour of silver eels in the forebay and at the plant intakes were identified. The study showed the key factor influencing both eel behaviour and the route taken through the plant was variation in river discharge. Escapement rate was related to eel length and the spill flow to river flow ratio, which could be described by a logistic regression model. The surface bypasses originally designed for salmon were found to aid downstream eel migration significantly. At velocities < 0.40 m·s−1, no eels, even the largest, for which the racks are a physical barrier, were found impinged on the trashracks. De 2004 à 2007, une étude sur la migration de dévalaison de l’anguille argentée européenne (Anguilla anguilla) a été menée sur la centrale hydroélectrique de Baigts sur le Gave de Pau dans le Sud-Ouest de la France. Cette étude, au cours de laquelle 116 individus ont été suivis par télémétrie PIT et radio, avait pour objectifs : (i) de déterminer les conditions de milieu propices à l’arrivée sur site et au franchissement de l’aménagement; (ii) de déterminer les taux d’échappement (passages par des voies autres que les turbines); (iii) d’analyser le comportement des anguilles devant les ouvrages et la perméabilité des grilles de la prise d’eau en fonction de la taille des individus; (iv) de tester la fonctionnalité, pour l’anguille, d’exutoires de surface ...