Aquaculture Slaughter Methods: Welfare Standards for Farmed Fish

Slaughter methods for farmed fish vary widely in their welfare implications. Evidence-based stunning and slaughter standards are essential for reducing the suffering of billions of fish annually.

Key Facts

Percussive stunning — a sharp blow to the head — is one of the most humane methods for fish slaughter
Carbon dioxide immersion causes significant distress before insensibility and is considered inhumane
Live chilling in ice slurry without prior stunning is widely used but causes prolonged suffering
Electrical stunning is effective for many species but parameters must be calibrated for species and size
RSPCA Assured and other welfare certification schemes specify stunning requirements for farmed fish

Welfare Considerations

Fish slaughter welfare is among the highest-priority issues in aquaculture welfare given the scale of fish farming — hundreds of billions of fish are slaughtered annually for food. Many common slaughter methods cause prolonged suffering: asphyxiation in air, live chilling without stunning, and CO2 immersion all cause distress before insensibility. Humane slaughter requires stunning to insensibility before or coinciding with death. Percussive stunning, electrical stunning, and high-concentration CO2 followed immediately by cutting all achieve rapid insensibility when properly applied. Consumer demand for welfare-certified fish products creates market incentives for farms to adopt better slaughter systems. Certification schemes that require pre-slaughter stunning are the most effective market tools for driving improvement.

What You Can Do

Choose farmed fish products certified to schemes requiring pre-slaughter stunning
Support regulatory requirements for humane fish slaughter standards
Ask retailers about the slaughter methods used in their farmed fish supply chains
Advocate for fish to be included in national animal welfare legislation covering slaughter