Fish passage facilities at dams allow migratory fish to navigate river barriers, with welfare implications for fish experiencing passage stress, injuries, and energetic costs during upstream migration.
Fish passage welfare extends beyond simple passage rates to encompass the energetic cost, injury risk, and behavioral stress of navigating artificial barriers. Fish that attempt passage at ladders or lifts experience elevated cortisol, energetic depletion, and physical injury risks that reduce their subsequent survival and reproductive success even if they technically pass. The welfare and conservation calculus increasingly favors dam removal over passage technology for rivers where dams provide modest economic value - the Elwha River dam removal in Washington dramatically demonstrated the welfare and population benefits of barrier elimination. Fish welfare considerations should be incorporated into dam licensing renewal decisions.