Cleaner Fish Welfare in Salmon Farms

Welfare science for wrasse and lumpfish used as cleaner fish in salmon aquaculture, examining their mortality rates, disease risks, and the welfare cost of using one species to benefit another.

Key Facts

Wrasse and lumpfish are deployed in Atlantic salmon farms to remove sea lice through natural grooming behavior
Annual mortality rates for cleaner fish in salmon cages commonly exceed 50%, with many farms reporting losses above 80%
Cleaner fish are often stocked without adequate shelter, appropriate social environments, or species-specific diets
Wrasse are wild-caught from coastal fisheries, raising conservation concerns alongside welfare issues in farming
Lumpfish are cold-adapted and may suffer thermal stress in warmer areas of salmon pens
Cleaner fish have demonstrable cognitive abilities including spatial learning and individual recognition
The welfare of cleaner fish has received far less attention than the salmon they serve despite comparable evidence of sentience

Welfare Considerations

Cleaner fish welfare represents a striking ethical blind spot in salmon aquaculture — fish with demonstrable cognitive capacity and welfare needs are deployed in conditions causing extraordinary mortality, with their suffering rarely acknowledged in discussions of salmon welfare improvements. The logic of using one sentient species to benefit another without adequate welfare consideration for the first raises profound ethical questions. Best practice cleaner fish management requires species-appropriate shelter structures in salmon cages, adequate and species-correct nutrition, management of thermal stress, and stocking densities that do not overwhelm social behavior. The development of alternative louse management strategies that do not rely on cleaner fish would eliminate these compounded welfare concerns.

What You Can Do

Support salmon aquaculture certification that explicitly addresses cleaner fish welfare standards
Advocate for research into alternative sea lice management approaches that eliminate cleaner fish welfare costs
Ask salmon producers and certification bodies what mortality rates and welfare standards they track for cleaner fish
Learn about wrasse and lumpfish biology to understand why current deployment conditions cause such high mortality
Support wild wrasse fishery management that prevents cleaner fish sourcing from depleting coastal populations