Fish Stunning Methods: Welfare at the Point of Slaughter

The method used to stun fish before slaughter has profound welfare implications. Evidence-based stunning practices can dramatically reduce suffering at the end of life for billions of fish annually.

Key Facts

Global aquaculture and wild capture fisheries kill an estimated 1-2.3 trillion fish annually.
Many fish are slaughtered without prior stunning, exposing them to prolonged consciousness during killing.
Percussive stunning (a sharp blow to the head) is effective for many species when applied correctly and consistently.
Electrical stunning can render fish immediately insensible but requires correct voltage, frequency, and duration.
CO2 stunning, still common in salmon processing, causes an aversive acidic response before unconsciousness.
Hypothermia (ice slurry) does not cause unconsciousness and is considered inhumane by welfare scientists.
The humane slaughter of fish is regulated in some EU countries but largely unregulated globally.

Welfare Considerations

The welfare of fish at slaughter is one of the most impactful areas for farmed and wild-caught fish, given the sheer numbers involved. Sentience-based evidence indicates fish have nociceptors, stress response systems, and learning abilities consistent with capacity to suffer. Methods like ice slurry immersion — which slowly chill fish without inducing insensibility — likely cause prolonged distress. Percussive and electrical stunning, when properly calibrated and monitored, can achieve rapid insensibility. The fish welfare community, led by organisations like the Fish Welfare Initiative, advocates for regulatory requirements and industry adoption of effective pre-slaughter stunning across species.

What You Can Do

Support the Fish Welfare Initiative and similar organisations advocating for improved slaughter standards.
Ask seafood retailers and restaurants about their sourcing standards for fish welfare at slaughter.
Support regulatory campaigns requiring mandatory fish stunning before slaughter in your country.
Choose Aquaculture Stewardship Council (ASC) certified seafood, which includes welfare requirements.
Reduce overall fish consumption or shift toward lower-sentience species if welfare is a concern.