Freshwater fish in rivers face multiple human-caused threats including pollution, barriers to migration, water abstraction, and invasive species. Addressing these threats improves welfare for billions of wild fish.
River fish welfare is intimately linked to river health. Fish experiencing oxygen-depleted water from sewage pollution suffer physiological stress equivalent to slow suffocation. Gill damage from agricultural chemical runoff causes chronic respiratory impairment. Barriers to migration trap fish below weirs, preventing spawning behaviour they are physiologically driven to complete. When salmon fail to reach spawning grounds, they die without reproducing — a welfare and population double failure. River restoration that removes barriers, improves water quality, and restores natural flow regimes delivers welfare benefits to the billions of individual fish that inhabit freshwater systems. River welfare is an arena where ecological restoration and individual animal welfare align precisely.