River fish welfare is affected by temperature, flow, and habitat quality; climate change is creating welfare challenges for cold-water species through river warming and reduced summer flows.
River fish welfare is shaped by the physical and chemical characteristics of their habitat, which humans increasingly affect through abstraction, warming, and pollution. Temperature is the most welfare-significant variable for cold-water species: above threshold temperatures, fish experience metabolic stress, immune suppression, and eventually lethal conditions. River management interventions including riparian shading through tree planting, abstraction limits, and fish passage can significantly improve individual fish welfare by maintaining the temperature and flow conditions these species require.