Humane slaughter of farmed fish is a critical welfare issue with growing regulatory attention and diverse technical solutions across species and production systems.
Fish slaughter welfare has advanced significantly from a state of near-complete neglect to active regulatory attention over the past two decades. Common methods including live ice slurry chilling, carbon dioxide exposure, and asphyxiation in air cause prolonged periods of consciousness and distress. Percussive stunning using automated percussors for salmonids is highly effective when properly calibrated. Electrical stunning with species-appropriate parameters induces immediate insensibility before killing. The challenge is that optimal parameters differ significantly between species, and many aquaculture systems operate with limited post-stun assessment. Ensuring that fish are stunned before gill cutting and that stunning is immediately followed by brain destruction or bleeding are the core welfare requirements.