Farmed Salmon Pre-Slaughter Welfare: Crowding and Stunning Standards

The final hours before slaughter are among the most welfare-critical periods for farmed salmon, with crowding, handling, and stunning practices all affecting suffering.

Key Facts

Atlantic salmon are the most farmed salmonid species globally with production exceeding 2.7 million tonnes annually
Pre-slaughter crowding during harvest causes acute hypoxia, scale loss, and elevated stress hormones
CO2 stunning is widely used but is now considered inhumane due to the aversive drowning-like sensation it causes
Percussive stunning and electrical stunning are considered more humane alternatives with rapid sensory loss
RSPCA Assured and other welfare certification programs require humane stunning standards for farmed salmon

Welfare Considerations

Pre-slaughter salmon welfare has improved significantly in recent years, driven by retailer pressure and welfare certification programs. The shift away from CO2 narcosis toward percussive and electrical stunning represents one of the most impactful welfare improvements in large-scale aquaculture. Crowding before harvest remains a welfare challenge even with improved stunning, as high density causes injury and stress during the gathering process. Innovations including low-stress crowding nets and real-time oxygen monitoring during harvest are improving pre-slaughter welfare at scale.

What You Can Do

Choose farmed salmon with welfare certifications requiring humane pre-slaughter stunning
Ask retailers about their salmon supplier stunning requirements
Support organizations working to establish legally binding humane slaughter standards for fish
Reduce farmed salmon consumption or shift to certified welfare-friendly options where available