Salmon slaughter methods vary widely in their welfare implications, and the industry is under increasing pressure to adopt humane killing methods that minimize pre-death suffering.
Salmon slaughter welfare is determined by the interval between initial handling and loss of consciousness. Methods that cause fear, pain, or distress before unconsciousness are welfare problems regardless of their brevity. CO2 immersion causes avoidance behavior and distress before fish lose consciousness, making it a welfare-compromised method despite its wide use. Percussion stunning applied correctly renders fish immediately unconscious before the killing cut. Electrical stunning is effective but requires proper calibration to ensure adequate voltage. Welfare certification schemes are increasingly requiring percussion or electrical stunning, driving industry investment in more humane equipment.