Farmed Salmon Lice Biological Control Welfare

Cleaner fish used as biological sea lice control in salmon farms face severe welfare problems from mortality, disease, and conditions poorly suited to their behavioral and physiological needs.

Key Facts

Cleaner fish including wrasse and lumpfish are used to eat sea lice from salmon in farm pens
Wrasse mortality in salmon farms commonly reaches 50-80% — among the highest mortality rates in aquaculture
Cleaner fish have specific habitat needs — wrasse need shelter structures and appropriate water temperature
Lumpfish are increasingly used as they tolerate colder Norwegian waters, but face their own welfare challenges
Welfare standards for cleaner fish are significantly less developed than for farmed salmon

Welfare Considerations

Cleaner fish welfare is one of the most neglected welfare issues in salmon aquaculture. Fish introduced to salmon pens to eat sea lice experience extreme mortality from disease, salmon aggression, and inappropriate environmental conditions. The wrasse and lumpfish used as cleaner fish have behavioral and physiological needs that standard salmon pens do not meet — wrasse need shelter structures and appropriate temperatures that salmon pens may not provide. High mortality rates are accepted as a production cost rather than recognized as a welfare failure. Developing welfare standards for cleaner fish, and reducing dependence on them through alternative lice management, are parallel welfare priorities.

What You Can Do

Support advocacy for welfare standards for cleaner fish used in salmon aquaculture
Choose welfare-certified salmon that addresses cleaner fish mortality as part of the welfare audit
Reduce salmon consumption given the welfare costs distributed across multiple species in the production system
Engage with organizations developing cleaner fish welfare standards for aquaculture certification