The final hours of a farmed salmon's life — crowding, chilling, and slaughter — present some of the most significant welfare risks in aquaculture. Better pre-slaughter practices can dramatically reduce suffering.
The pre-slaughter phase represents a concentrated welfare risk for farmed salmon. Crowding causes cortisol spikes, physical injury from conspecific contact, and in dense crowds, hypoxia. Subsequent chilling or CO2 exposure before slaughter — used to sedate fish — is aversive for significant periods before causing unconsciousness. Slaughter without any prior stunning — still practiced in some facilities — causes a prolonged death from asphyxiation or exsanguination while fully conscious. The welfare solution is clearly established: electrical stunning immediately before slaughter renders fish unconscious in under one second with no evidence of suffering; percussive stunning provides a reliable back-up. Requiring these methods across all farmed salmon production is a technically achievable regulatory goal that would benefit billions of fish annually.