Aquaculture Welfare: Humane Harvest Methods

Harvest methods in aquaculture cause significant acute welfare harm; improved stunning and killing procedures represent one of the most actionable welfare improvements available.

Key Facts

CO2 stunning of farmed fish is effective but causes prolonged aversive experience before unconsciousness
Percussive stunning using a blow to the head is instantaneous but requires skill and is difficult at scale
Electrical stunning provides immediate unconsciousness and is increasingly automated in salmon harvest
Brain destruction by spiking (ike jime) immediately after stunning ensures death without recovery
Harvest density management including reduced feeding before crowding reduces stress before slaughter

Welfare Considerations

Fish harvest causes welfare harm through a combination of crowding stress, oxygen depletion, handling injury, and killing procedures that may cause prolonged suffering before death. CO2 stunning, while widely used, causes a prolonged aversive experience as CO2 levels build up before loss of consciousness. Percussive and electrical stunning cause immediate unconsciousness but require careful application at commercial speed. Pre-harvest management including fasting periods and reduced crowding speeds reduce acute stress before killing. Investment in electrical stunning systems for commercial aquaculture represents the most practical welfare improvement available at scale.

What You Can Do

Choose aquaculture products from certified farms that document humane harvest methods
Support certification schemes that require effective pre-slaughter stunning of farmed fish
Advocate for harvest welfare standards to be included in all aquaculture certification schemes
Learn about fish slaughter welfare science to engage effectively with aquaculture welfare policy debates