Farmed Fish Slaughter: Current Methods and Welfare Standards

Slaughter methods for farmed fish vary widely, with significant welfare consequences depending on whether effective stunning is applied before killing begins.

Key Facts

CO2 narcosis — commonly used for salmon — causes an aversive swimming response before loss of consciousness
Asphyxiation on ice is still used for some species, causing death over several minutes
Percussive stunning renders fish insensible within seconds when correctly applied
Electrical stunning is effective for salmon but requires precise parameters calibrated to species and size
EFSA concluded in 2009 that fish have the capacity to experience pain and that slaughter methods should minimize suffering

Welfare Considerations

Fish slaughter welfare has improved significantly in leading aquaculture nations but remains highly variable globally. The welfare hierarchy for fish slaughter is broadly: percussive or electrical stunning (best), rapid asphyxia in ice slurry (moderate), CO2 narcosis (aversive), live chilling alone (prolonged and distressing), and asphyxiation in air (most distressing). Consumer purchasing choices that favor certified humanely slaughtered fish, and retailer sourcing requirements that mandate pre-slaughter stunning, can drive industry-wide improvement in this poorly regulated aspect of aquaculture welfare.

What You Can Do

Choose farmed fish products certified under welfare standards specifying humane pre-slaughter stunning
Ask retailers what slaughter method standards they require from farmed fish suppliers
Support regulatory campaigns for mandatory pre-slaughter stunning in national aquaculture legislation
Reduce farmed fish consumption to decrease demand on systems with inconsistent slaughter welfare standards