Salmon Sea Lice Cleaner Fish Welfare: Wrasse and Lumpfish

Cleaner fish used to control sea lice in salmon farms have their own welfare needs that are often inadequately met, creating a situation where one welfare solution introduces another welfare problem.

Key Facts

Millions of wrasse and lumpfish are deployed annually in Norwegian salmon farms for biological lice control
Wrasse are collected from wild populations, raising conservation and capture welfare concerns
Cleaner fish suffer high mortality in salmon farms due to water temperature extremes and mechanical delousing collisions
Lumpfish bred in hatcheries have better temperature tolerance than wrasse but still face welfare challenges in farm environments
Only 10-30% of cleaner fish survive a full salmon production cycle in most farm environments

Welfare Considerations

Cleaner fish welfare represents a case where solving one welfare problem, sea lice burden on salmon, has introduced another. Wrasse and lumpfish deployed in salmon pens face water temperature extremes unsuitable for their physiology, mechanical hazards from delousing equipment, and competition for hiding places and food. Their high mortality rates indicate fundamentally inadequate conditions. A truly welfare-informed approach to biological sea lice control must address cleaner fish welfare as seriously as host salmon welfare, including species matching to temperature ranges, adequate shelter structures, and supplementary feeding.

What You Can Do

Support salmon certification schemes that include cleaner fish welfare standards alongside salmon welfare
Advocate for wild wrasse collection to be phased out in favour of hatchery-bred cleaner fish
Support research developing better cleaner fish housing conditions that reduce mortality rates
Choose salmon from producers committed to integrated welfare management for both salmon and cleaner fish