The method of slaughter is a critical welfare decision point in salmon farming, with significant differences between industry-standard methods in the pain and stress experienced by fish at the end of their lives.
Salmon slaughter welfare has received increasing scientific and policy attention as evidence of fish sentience has accumulated. The traditional method of allowing fish to asphyxiate on ice or in air causes prolonged suffering in animals that, while they cannot vocalise distress, show physiological and behavioural indicators of stress and pain for extended periods after crowding begins. Electrical stunning that renders fish unconscious before crowding and slaughter substantially reduces this suffering. The welfare improvement is significant and the cost is modest relative to total production cost. The barriers are industry inertia, lack of regulatory requirements in most salmon-producing countries, and consumer unawareness that salmon slaughter welfare varies between products and certifications.