Cleaner Fish Welfare in Salmon Farming

The emerging welfare challenge of wrasse and lumpfish used to control sea lice in salmon farms.

Key Facts

Approximately 50 million cleaner fish are deployed annually in Norwegian and Scottish salmon farms
Ballan wrasse and lumpfish are the primary species used to remove sea lice from salmon
Cleaner fish mortality rates in sea cage deployment can reach 50-80% within months
Wild-caught wrasse face welfare costs of capture, transport, and adaptation to sea cage conditions
Lumpfish are hatchery-produced but face the same sea cage stress and predation risks as wild wrasse
Welfare standards for cleaner fish significantly lag behind those for the salmon they service

Welfare Considerations

Cleaner fish welfare represents an emerging and largely neglected welfare challenge that arises directly from the biological control approach to sea lice management - an approach otherwise welfare-positive compared to chemical treatments. The very high mortality rates of cleaner fish in sea cage deployment indicate severe welfare compromise, as fish are exposed to novel environments, predation, and physical trauma from salmon interactions. The moral consideration of cleaner fish welfare is contested by some who argue their sentience is uncertain, but precautionary reasoning combined with the evidence of stress responses supports welfare improvement investment. The welfare calculus of biological sea lice control must account for cleaner fish welfare costs.

What You Can Do

Support salmon producers who monitor and report cleaner fish mortality rates
Advocate for cleaner fish welfare standards alongside salmon welfare requirements
Choose salmon with certification schemes that include cleaner fish welfare auditing
Support research into deployment conditions that reduce cleaner fish mortality
Learn about the welfare implications of biological sea lice control approaches
Ask salmon retailers about cleaner fish welfare standards in their supply chains