Improved migration survival of European eels at Swedish hydropower plants

Hydropower plants pose a major threat to the critically endangered European eel, including through barriers to migration and direct mortality in turbines. This project investigates eel migration past three hydropower plants in the Kävlingeån River, both before and after legally required fish passage facilities were constructed. The study will provide important knowledge to support Sweden's nation-wide review of the environmental conditions governing hydropower operations.

The project aims to 

1. Assess mortality during migration past three hydropower plants throughout the year, before fish passage facilities were constructed (2023–2024).
2. Assess mortality and migration route selection past the same three hydropower plants throughout the year, after fish passage facilities were constructed (2027–2028).
3. Determine long-term migration behaviour in eels before and after the construction of fish passage facilities, including differences between naturally recruited and stocked eels (2023–2029).

The knowledge generated by the project is expected to be central to the extensive reviews of hydropower environmental conditions that began in 2022 and will continue for approximately 20 years. As such, the results can directly contribute to better-designed measures to protect eels and other migratory species at hydropower plants throughout Sweden.

The study is conducted in the Kävlingeån River in Skåne, which has been designated as an index river for the EU eel monitoring programme since 2019. The project also benefits from existing infrastructure for fish counting and tagging at Håstad mölla.

Participants

Josefin Sundin (projektledare, docent SLU Aqua)
Philip Jacobson (forskare SLU Aqua)
Eirik Ryvoll Åsheim (forskare SLU Aqua)
Eklövs Fiske och Fiskevård
Fiskevårdsteknik AB