Fish passage structures that help migratory fish navigate dams and other barriers have both conservation and welfare benefits by enabling successful migration and reducing exhaustion mortality.
Fish ladders and bypass channels serve welfare functions by reducing the energy expenditure and injury risk associated with failed barrier negotiation attempts. Fish that repeatedly attempt and fail to pass barriers experience exhaustion, physical damage from turbulent flows, and ultimately death before reaching spawning grounds. Effective passage structures reduce this individual suffering while also supporting population recovery. Dam removal is the most welfare-positive solution where feasible, eliminating the passage challenge entirely. For existing barriers, bypass channels designed using swimming performance data for target species produce better passage rates and lower energy costs than poorly designed ladders.