Farmed Salmon Welfare at Harvest

The harvest of farmed salmon involves a sequence of procedures — crowding, pump transfer, stunning, and killing — each with specific welfare implications for billions of fish annually.

Key Facts

Global farmed salmon production exceeds 2.7 million tonnes annually, involving billions of individual fish.
Pre-harvest crowding of fish to facilitate pump transfer causes acute stress measurable through cortisol spikes.
Percussion stunning (a blow to the head) and electrical stunning can achieve insensibility in fish within seconds when applied correctly.
CO2 stunning — immersion in carbon dioxide-saturated water — causes aversion behaviour suggesting a painful experience before insensibility.
The Five Domains model is increasingly applied to farmed salmon welfare assessment, covering nutrition, environment, health, and behaviour.

Welfare Considerations

Salmon harvest welfare is among the most consequential issues in food animal welfare given the scale involved. Each farm harvests hundreds of thousands to millions of fish, making welfare improvements at harvest extraordinarily impactful in aggregate. Evidence consistently shows CO2 stunning is the most welfare-compromising method available, with fish showing avoidance behaviour suggesting a painful experience. Percussion and electrical stunning achieve rapid insensibility with far lower welfare costs and are available alternatives.

What You Can Do

Choose farmed salmon from producers certified by schemes requiring humane stunning at harvest.
Support campaigns demanding the phase-out of CO2 stunning in salmon processing facilities.
Advocate for mandatory stunning standards in aquaculture legislation in your country.
Reduce farmed salmon consumption where welfare-certified alternatives are not available.