Against all odds: silver eel mortality in the River Meuse in a population perspective

No abstracts are to be cited without prior reference to the author.

European eel Anguilla anguilla is in strong decline. Among many factors, hydropower and fisheries mortality during the downstream migration of silver eels in rivers plays an important role. To determine the impact of hydropower and fisheries on silver eel in the River Meuse, radio-telemetry experiments were performed during 2002-2006. For this study, 18 fixed detection stations (Nedap Trail-System®) covering the entire river width at different sections in the River Meuse, and 2 stations were used covering the entrance of each of the the two hydropower plants. This allowed to distinguish individuals entering the turbine from individuals passing over the adjacent weir. Recaptures in fisheries were used to assess fisheries mortality. In - total 300 silver eels were surgically implanted with Nedap-transponders. Per stretch between stations mortality rates were assessed and attributed to the different factors. To determine the overall effect on the escapement of silver eels from the River Meuse, insight in the distribution of starting silver eel along the catchment of the River Meuse is required. Here, data for yellow eel distribution, and total fluxes of silver eel at two locations are used to illustrate distribution patterns. Consequences on the population level of the Meuse catchment and management are discussed.