Aquaculture

Sea Lice in Salmon Farming: Welfare Impact

Sea lice infestations are the leading health and welfare challenge in Atlantic salmon aquaculture, causing significant suffering and economic losses.

Key Facts

Sea lice feed on mucus, skin, and blood of farmed salmon, causing open wounds
Severe infestations can expose salmon cranium and cause death from osmoregulatory failure
Chemical treatments are becoming less effective as lice develop resistance
Biological control using cleaner wrasse fish raises its own welfare questions
Norway spends over 500 million euros annually on sea lice treatments

Welfare Considerations

Sea lice infestations cause chronic pain through open lesions and physiological stress from osmoregulatory disruption. Heavily infested fish show reduced feeding, abnormal swimming, and social withdrawal. Chemical delousing treatments involve immersion in concentrated solutions that cause acute stress responses. Mechanical delousing using pressurised water causes physical injury. The welfare burden from sea lice across the global salmon industry is enormous.

What You Can Do

Choose salmon certified to standards that monitor and limit lice burdens
Ask retailers about sea lice treatment policies of their suppliers
Support research into lice-resistant salmon genetics
Advocate for welfare standards for wrasse used as cleaner fish
Reduce salmon consumption until welfare standards improve significantly