Genetic Effects of Hydropower Development on Fish Populations, with Special Focus on the River Ljungan

This report, commissioned by the County Administrative Boards of Västernorrland and Jämtland, Sweden, synthesizes scientific knowledge on the genetic and evolutionary impacts of hydropower-related fragmentation on fish populations, with a specific focus on the River Ljungan watershed in central Sweden. It highlights risks of reduced gene flow, increased genetic differentiation, loss of genetic diversity, and reduced adaptive potential, and provides recommendations for integrating genetics into hydropower licensing assessments and restoration planning.