Salmon Sea Lice and Cleaner Fish Welfare in Aquaculture

The use of cleaner fish like wrasse and lumpfish to control sea lice in salmon aquaculture raises important welfare questions for both species.

Key Facts

Sea lice are external parasites causing tissue damage, stress, and reduced immunity in Atlantic salmon
Cleaner fish including wrasse and lumpfish eat sea lice off salmon, reducing chemical treatments
Cleaner fish are often caught wild rather than farmed, with welfare concerns during capture and transport
Wrasse have complex social systems and require enriched environments with hiding places
Cleaner fish mortality rates are very high in some farms - 80-100% within a season
Genetic selection and farming improvements are improving cleaner fish welfare outcomes

Welfare Considerations

The use of cleaner fish represents a welfare trade-off - reducing sea lice chemical treatments on salmon while introducing welfare risks for the cleaner fish themselves. Wrasse are cognitively complex fish capable of tool use and social learning; their welfare needs are substantial. High mortality rates indicate that current welfare standards for cleaner fish in salmon aquaculture are often inadequate. Improved farming, deployment, and retirement protocols are urgently needed.

What You Can Do

Support salmon aquaculture certified to standards covering cleaner fish welfare
Ask salmon producers about their cleaner fish sources and mortality rates
Advocate for welfare standards specific to cleaner fish in aquaculture regulations
Support research into wrasse and lumpfish welfare needs and appropriate husbandry
Reduce farmed salmon consumption if cleaner fish welfare standards are not met
Donate to organizations researching integrated pest management alternatives to cleaner fish