Fish Stunning Methods at Slaughter

Effective stunning before slaughter is a critical welfare intervention for farmed fish, but method choice varies widely and implementation quality remains inconsistent.

Key Facts

Carbon dioxide stunning is commonly used but causes distress before inducing unconsciousness
Electrical stunning can be effective but requires species-specific parameters to work correctly
Percussive stunning by a blow to the head is quick when applied correctly but requires training
Many farmed fish are killed without any prior stunning in some production systems
The RSPCA and other welfare bodies have developed fish-specific slaughter welfare standards
Research on fish pain and consciousness has advanced significantly since 2000 supporting welfare-focused slaughter

Welfare Considerations

The welfare significance of pre-slaughter stunning for fish is now supported by substantial scientific evidence that fish experience pain and distress. CO2 immersion — still widely used — causes aversive reactions and prolonged consciousness before death, representing a significant welfare failure at scale. Electrical stunning, when properly calibrated for species and size, can render fish instantaneously unconscious. Percussive stunning is effective for larger fish when trained staff apply it correctly. Welfare during slaughter is one of the most impactful areas for improving fish welfare because it affects the final minutes of every animal killed in production.

What You Can Do

Choose fish products with welfare certification covering slaughter methods such as RSPCA Assured
Advocate for mandatory pre-slaughter stunning requirements in aquaculture regulations
Support research into optimal electrical stunning parameters for different fish species
Ask retailers and restaurants about the slaughter welfare standards of their fish suppliers
Raise awareness that fish welfare at slaughter is a legitimate and serious welfare concern