Rainbow trout is the most widely farmed salmonid in Europe, with welfare challenges in intensive flow-through raceways including crowding, aggression, and pre-slaughter practices.
Rainbow trout in intensive raceways face welfare challenges from high density, restricted swimming opportunities, and social stress from aggression. As active, schooling predators, trout in crowded conditions cannot establish stable social hierarchies, leading to persistent aggression. Poor water quality causes chronic physiological stress. While pre-slaughter electrical stunning is more widely adopted in trout production than in marine aquaculture, inconsistent stun quality and inadequate implementation in smaller operations remain welfare concerns.