Rainbow trout is one of the most widely farmed fish globally, with welfare challenges centered on crowding stress, disease management, water quality requirements, and humane slaughter practices.
Trout welfare in aquaculture involves chronic welfare challenges from production conditions and acute welfare concerns at slaughter. High stocking densities cause competitive stress, fin damage from aggressive interactions, and chronic cortisol elevation that impairs immune function and growth. The cold, well-oxygenated water requirements of trout means that summer heat waves create welfare emergencies at farms in marginal thermal zones. Disease events including IPN outbreaks cause suffering across large populations simultaneously. Slaughter welfare has improved as CO2 narcosis has been recognized as aversive — the alternative of percussive stunning induces rapid insensibility when properly applied. Consumer purchasing through certification schemes that include specific welfare and water quality requirements drives producer investment in welfare improvement across the industry.