Rainbow trout is one of the most widely farmed fish globally. Welfare issues including density stress, aggression and slaughter methods require ongoing improvement.
Trout welfare science benefits from decades of research that has established density thresholds, aggression management strategies and slaughter protocols with reasonable evidence bases. Despite this, industry practice frequently falls short of research recommendations. High densities increase aggressive interactions and fin damage, reducing welfare for subordinate fish disproportionately. Slaughter welfare varies significantly between operations — percussive stunning correctly applied provides rapid insensibility, while poorly executed electroimmobilisation may produce immobility without unconsciousness. Welfare certification schemes for trout provide a pathway for producers to demonstrate compliance with evidence-based standards.