Farmed Fish Pre-Slaughter Stunning: Progress and Remaining Gaps

Effective pre-slaughter stunning of farmed fish before killing is a critical welfare intervention, with significant variation in adoption and quality across species and regions.

Key Facts

The welfare requirement for unconsciousness before killing applies to farmed fish as strongly as to farmed mammals
Electrical stunning correctly applied achieves rapid unconsciousness in Atlantic salmon and trout
Percussive stunning is used for smaller fish but requires careful calibration to ensure effectiveness
CO2 narcosis — still used in some fisheries — causes aversive sensations before unconsciousness
RSPCA Assured, Naturland and some other certification schemes require specific stunning methods
Stunning effectiveness can be reduced by fish size variation, electrode positioning and electrical parameter errors

Welfare Considerations

Pre-slaughter stunning is the single most impactful welfare intervention available at the time of fish killing. Effective stunning followed by immediate killing eliminates the suffering of conscious fish during the slaughter process. The variable adoption of effective stunning methods across aquaculture operations means many farmed fish are still killed without effective stunning. Regulatory requirements and certification standard requirements are the most reliable mechanisms for ensuring consistent adoption of humane pre-slaughter practices.

What You Can Do

Choose farmed fish products certified by schemes requiring effective pre-slaughter stunning
Advocate for mandatory pre-slaughter stunning requirements in aquaculture welfare legislation
Support certification bodies strengthening their stunning requirements and auditing protocols
Ask retailers and restaurants about the slaughter standards of their aquaculture suppliers
Support research into improved stunning technologies for species where current methods are less reliable