Farmed Salmon Sea Lice: Biological Control Welfare

Biological sea lice control using cleaner fish offers welfare advantages over chemical treatments but introduces new welfare considerations for the cleaner species.

Key Facts

Wrasse species including goldsinny, corkwing, and ballan are used alongside lumpfish as cleaner fish
Wild-caught wrasse constitute a significant proportion of cleaner fish used in Norwegian salmon farming
Wrasse mortality in salmon cages is significantly higher than in their natural reef habitats
Lumpfish can be produced in hatcheries, reducing wild capture pressure compared to wrasse
Research into wrasse welfare including appropriate diet, shelter, and density is rapidly advancing

Welfare Considerations

Biological sea lice control using cleaner fish exemplifies the welfare complexity of aquaculture: a method adopted partly to improve salmon welfare creates welfare problems for the cleaner fish used. Wild-caught wrasse removed from their complex reef habitats into salmon cage environments experience significant welfare harm from habitat deprivation, inappropriate diet, and high mortality from salmon aggression and disease. The welfare obligation requires addressing cleaner fish welfare with the same seriousness applied to salmon welfare, rather than treating them as expendable inputs to salmon production.

What You Can Do

Support salmon certification schemes that require cleaner fish welfare standards
Advocate for transition from wild-caught to hatchery-produced cleaner fish
Support research into cleaner fish welfare requirements and husbandry improvements
Choose certified salmon products from operations with transparent cleaner fish welfare documentation
Learn about the welfare implications of different sea lice control methods