Aquaculture

Farmed Salmon Sea Lice Management

Sea lice are the most significant welfare and production challenge in Atlantic salmon farming. Infestations cause pain, tissue damage, and increased susceptibility to disease.

Key Facts

Heavy sea lice burdens cause erosion of skin and flesh, particularly around the head and back of salmon
Lice from farms can spread to wild salmon smolts migrating past open-net pen sites
Cleaner fish like wrasse and lumpfish are used as biological controls but have high mortality rates themselves
Mechanical delousing treatments including warm water and laser systems cause acute stress

Welfare Considerations

Sea lice management creates a welfare dilemma: infestations cause chronic pain and tissue damage, while treatments cause acute stress. Neither outcome is satisfactory. Closed containment systems that physically exclude lice offer the most complete solution but require higher capital investment. Improving cleaner fish welfare and developing less stressful mechanical treatments are important intermediate steps.

What You Can Do

Support transition to closed containment salmon farming that excludes sea lice
Choose salmon from farms with verified low sea lice counts and minimal treatment frequency
Advocate for welfare standards covering cleaner fish mortality rates in salmon farming
Support research into sea lice vaccines as an alternative to mechanical and chemical treatment