Farmed Salmon Lice Treatment Welfare

Sea lice treatments in salmon farming cause significant welfare harm and represent a major challenge for the industry.

Key Facts

Sea lice infestations affect virtually all open-net salmon farms and require repeated treatment interventions
Thermal treatment involves submerging fish briefly in hot water — an acutely stressful procedure
Freshwater treatments use osmotic shock to kill lice and cause measurable physiological stress
Mechanical delousing using hydraulic or rotary systems causes physical injury and mortality
Genetic selection for lice resistance and closed-containment systems offer longer-term welfare solutions

Welfare Considerations

Sea lice treatment in salmon farming causes repeated acute welfare events throughout the production cycle. Each treatment — whether thermal, freshwater, mechanical, or chemical — stresses fish, causes some mortality, and may cause injury. The frequency of these interventions in conventional open-net farming makes lice management one of the dominant welfare challenges in salmon aquaculture. Preventive approaches including closed-containment farming and genetic resistance breeding reduce the need for treatment interventions.

What You Can Do

Choose salmon from closed-containment aquaculture operations with lower lice pressure
Support regulations requiring welfare impact assessment for sea lice treatment methods
Reduce salmon consumption from conventional open-net farms
Support research into lice-resistant salmon genetics and vaccination approaches
Follow the Aquaculture Stewardship Council's developing welfare standards for salmon