Wild Atlantic salmon populations in UK rivers have declined dramatically. River restoration efforts have welfare implications for individual fish as well as population-level benefits.
Wild salmon welfare during migration involves genuine suffering. Fish navigating degraded rivers with barriers, poor water quality, warm temperatures (salmon require cold, well-oxygenated water), and sea lice infestations are experiencing chronic physiological stress. Injury from attempts to pass weirs or falls, combined with the energetic cost of migration itself, means returning salmon are frequently in poor condition. River restoration that reduces these stressors has clear welfare benefits for individual fish, not only population-level conservation value.