Farmed Salmon Lice and Cleaner Fish Welfare

Cleaner fish — wrasse and lumpfish — are used to control sea lice on farmed salmon, but their welfare is often overlooked.

Key Facts

Cleaner fish (wrasse and lumpfish) eat sea lice from salmon, reducing chemical treatment dependence
Millions of cleaner fish are deployed in salmon farms annually across Scotland and Norway
Wrasse are primarily wild-caught, raising sustainability and welfare concerns for wild populations
Cleaner fish experience injury from salmon aggression and may be crushed during salmon feeding
Lumpfish are typically farmed but often treated with little welfare consideration given their pest control role
Mortality rates for cleaner fish in salmon farms are extremely high — often 50-100% per year

Welfare Considerations

Cleaner fish welfare is the invisible underside of a seemingly welfare-positive sea lice control strategy. The high mortality rates of wrasse and lumpfish in salmon farm environments — from salmon aggression, mechanical injury, and starvation — represent a significant welfare problem that is largely unaddressed. These are sentient fish whose welfare is sacrificed instrumentally for the welfare improvement of farmed salmon. A more complete welfare assessment of salmon aquaculture must include the cleaner fish. Welfare improvements require reducing wrasse wild capture, improving farm conditions that cause cleaner fish injury, and developing better sea lice control methods that do not depend on sentinel animals with extremely high mortality.

What You Can Do

Ask salmon producers about their cleaner fish welfare monitoring and mortality rates
Support research into alternatives to cleaner fish for sea lice control
Advocate for cleaner fish to be included in aquaculture welfare certification requirements
Choose salmon from systems that demonstrate genuine welfare commitment across the full system
Engage certification bodies about extending welfare standards to cleaner fish species