River rewilding through dam removal and habitat restoration dramatically improves the welfare of migratory fish and entire aquatic communities.
River rewilding delivers enormous welfare gains for migratory fish. Salmon blocked by dams cannot complete their life cycle - an evolutionary drive so strong that fish repeatedly attempt passage against barriers, exhausting themselves and suffering injury. Free-flowing rivers allow salmon to reach ancestral spawning grounds, complete reproduction and die naturally rather than failing to spawn at all. Beyond salmon, the complex habitats of rewilded rivers - pools, riffles, beaver dams, woody debris - support diverse fish populations with appropriate food, refuge and spawning habitat. The welfare of individual fish in restored rivers is measurably better: fewer parasites, better body condition, more successful reproduction and natural behavior expression.