Salmon Pre-Slaughter Welfare: Stunning and Killing Methods

The method of killing farmed salmon at harvest significantly affects their welfare. Percussive stunning, electrical stunning, and controlled atmosphere systems each have different efficacy and welfare profiles.

Key Facts

Norway produces over 1.5 million tonnes of farmed Atlantic salmon annually; pre-slaughter methods affect all of them
Traditional gill-cutting without prior stunning allows salmon to die over 5-7 minutes; this method causes prolonged suffering
Percussive stunning using a Steritek or similar device renders salmon insensible immediately when applied correctly
Electrical stunning with water bath systems is widely used but efficacy depends on current parameters being correctly set
CO2 euthanasia causes aversion in salmon before loss of consciousness; research shows distress during CO2 immersion
The RSPCA Assured salmon standard requires pre-slaughter stunning; this drives adoption in UK-certified farms
Norwegian regulations now require all farmed salmon to be stunned before killing; this standard is being adopted elsewhere
Research into brain activity post-stunning confirms rapid loss of consciousness with effective percussive methods

Welfare Considerations

Salmon pre-slaughter welfare is one of the areas where welfare science has translated most clearly into better practices. The evidence that gill-cutting without stunning allows salmon to remain conscious for minutes while dying in distress is unambiguous, and the technology for effective stunning is available and affordable at commercial scale. Norway regulatory action requiring stunning has driven industry adoption at scale, demonstrating that regulation can achieve rapid welfare improvements when evidence is clear and alternatives are feasible. The welfare dividend of universal stunning adoption would affect over a billion salmon annually, making it one of the highest-impact welfare improvements available in aquaculture.

What You Can Do

Choose farmed salmon from Norway, Scotland, or other jurisdictions with mandatory stunning requirements
Look for RSPCA Assured or equivalent certification that requires pre-slaughter stunning
Advocate for mandatory pre-slaughter stunning requirements for farmed fish in all major producing countries
Support the Aquatic Life Institute campaigns for farmed fish slaughter welfare standards
Ask retailers to source salmon only from farms with documented stunning protocols
Engage food service companies about their salmon supplier welfare standards at slaughter