Brown and rainbow trout are among the most studied fish for welfare purposes, with growing evidence informing both fisheries management and aquaculture practices.
Research on trout welfare has significantly advanced understanding of fish pain and suffering. Catch-and-release angling can cause acute pain, exhaustion, physiological stress, and increased susceptibility to predation after release. Handling time, air exposure, and water temperature critically affect post-release survival. Barbless hooks and wet-hand handling reduce injury. In aquaculture, rainbow trout suffer from crowding stress, elevated cortisol, immune suppression, and disease. Husbandry-related cataracts are a documented welfare problem linked to inadequate diet. Pre-slaughter electrical stunning is increasingly required and reduces suffering compared to asphyxiation. Hatchery fish released into rivers experience high mortality from predation and inability to forage naturally.