Rainbow trout are among the most widely farmed fish globally. Their welfare in intensive aquaculture is shaped by stocking density, water flow, oxygen levels, and handling during sorting and slaughter.
Trout welfare in aquaculture is compromised primarily by inadequate water flow, excessive stocking density, and inhumane slaughter practices. Without directional current, trout cannot express their natural orientation behavior and often show increased aggression and skin damage from fin-biting. Grading procedures, which involve netting and air exposure, cause acute stress events multiple times per production cycle. Asphyxiation in air or on ice remains the dominant slaughter method in many markets despite electrical stunning being technically proven and commercially viable. The welfare case for trout improvement is strong and the economic case is favorable as reduced stress improves flesh quality and reduces disease-related mortality.