Rainbow trout are one of the most widely farmed fish species globally. Their welfare in aquaculture is affected by crowding, water quality, handling stress, and slaughter methods.
Trout welfare science is more advanced than for many other farmed fish species. They show clear stress responses to crowding, handling, and water quality decline. Chronic stress suppresses immunity and promotes disease. Slaughter by live chilling or asphyxiation causes prolonged distress. Percussive or electrical stunning before slaughter significantly improves welfare at the point of death. Stocking density reductions and water quality management are proven welfare interventions.