Atlantic salmon aquaculture is the most welfare-scrutinized fish farming sector globally. Significant improvements have been made, but sea lice, crowding, and slaughter remain key challenges.
Salmon welfare has improved most significantly in slaughter practices, where Norway now mandates effective stunning. However, sea lice management remains a major welfare issue — treatment methods (chemical, thermal, mechanical) all cause acute stress and some physical injury. Thermal delousing (immersion in hot water) has raised particular welfare concerns. Crowding stress throughout the production cycle elevates baseline cortisol and compromises immune function. The industry is under increasing pressure from welfare certification schemes to demonstrate measurable welfare improvement.