A possible strong impact of tidal power plant on silver eels’ migration

• Published in: Estuarine, coastal and shelf science Vol. 278; p. 108116
• Main Authors: Trancart, Thomas, Teichert, Nils, Lamoureux, Jézabel, Gharnit, Elouana, Acou, Anthony, De Oliveira, Eric, Roy, Romain, Feunteun, Eric
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 05.11.2022; Elsevier
• Subjects: Acoustic telemetry; Anguilla Anguilla; Animal biology; Biodiversity and Ecology; Conservation policy; Environmental Sciences; Escapement; Hydropower plant; Life Sciences; Tidal power plant; Turbines; Vertebrate Zoology; Escapement; Hydropower plant; Tidal power plant; Conservation policy; Acoustic telemetry; Turbines; Anguilla Anguilla
• ISSN: 0272-7714; 1096-0015
• DOI: 10.1016/j.ecss.2022.108116

Very few tidal power plants exist in the world. The first one was built in the Rance estuary (Brittany, France) in 1966 and the second one in South Korea. However, with the increasing demand in renewable energy, other tidal power plant projects are being studied. These power plants are larger than unidirectional fluvial hydropower plants and strongly modify the natural tidal cycle in estuarine systems. As such, their effect on megafaunal movements might strongly differ from those caused by unidirectional fluvial hydropower plants and should be specifically considered and studied before the development of similar constructions. In this study, an acoustic telemetry array was deployed to track 25 silver eels released 16 km upstream of the Rance tidal power dam. Only 1/3 of the tagged eels passed the dam and reached the sea. Data suggested that eels interrupted their migration up to 5 km upstream of the dam. We assume that the noise and tidal disturbance generated by the dam could lead to a disruption of a high proportion of silver eels’ reproductive migration. •Tidal power plants represent a potential to produce carbon free electricity.•There effects on mobile fauna migration are scarcely documented.•We made a telemetry study to assess the eel migration through a tidal power plant.•Only 1/3 of the silver eels escape. 56% of the eels stay >5 km upstream the dam.•We speculate that noise and tidal cycle modification disrupt downstream migration.