Aquaculture

Farmed Salmon CO2 Stunning Debate and Welfare Evidence

CO2 stunning for farmed salmon remains controversial, with growing evidence suggesting it is aversive compared to alternatives.

Key Facts

CO2 is widely used to stun salmon before slaughter in Norwegian and Scottish aquaculture
Evidence from brain activity studies suggests CO2 causes distress before unconsciousness
Percussion stunning immediately followed by bleeding is considered more welfare-positive
Electrical stunning systems are available but require careful parameter calibration for species and size
Norwegian legislation now restricts CO2 stunning use and promotes alternative methods

Welfare Considerations

The scientific evidence that CO2 stunning causes aversion and distress before inducing unconsciousness is compelling enough to prompt regulatory action in Norway. The welfare case for transitioning to percussion or electrical stunning methods is strong. Consumer and regulatory pressure is driving industry investment in alternative approaches.

What You Can Do

Support salmon certification schemes that require non-CO2 pre-slaughter stunning
Advocate for regulatory restrictions on CO2 stunning in farmed fish slaughter
Choose salmon from producers committed to welfare-positive slaughter methods
Support research into practical, affordable alternatives to CO2 stunning