IMIS

Acoustic telemetry study of downstream-migrating silver European eel (Anguilla anguilla) in the High Rhine at the Swiss-German border (Stein am Rhein to Rheinau). From autumn 2026, silver eels are tagged with acoustic transmitters and tracked by an array of hydrophones across the study reach, including hydropower sites near Schaffhausen. The project characterises migration routes, timing, swimming speed in relation to flow, and passage behaviour at hydropower infrastructure, to inform eel-protection and fish-migration measures. Eels are taken from the Lake of Constance and the upper site of the river Rhein, tagging runs in two annual cohorts (2026 and 2027) with monitoring through 2029. Led by Fischwanderung GmbH (tag and receiver owner) in collaboration with Eawag, funded by the Swiss Federal Office for the Environment (FOEN/BAFU), Lotteriefonds Thurgau, Swisslosfonds Aargau and the 111er Club.