Sea Lice Biological Control Using Cleaner Fish: Welfare Challenges

Cleaner fish including wrasse and lumpfish are used to control sea lice on salmon. Their welfare is often neglected despite being sentient animals with specific needs.

Key Facts

Approximately 54 million cleaner fish were used in Norwegian salmon farming in 2022
Wrasse are wild-caught or hatchery-raised and deployed in salmon sea cages
Cleaner fish welfare needs are poorly served in standard salmon farm conditions
Wrasse require shelter structures, species-appropriate food, and protection from salmon aggression
Cleaner fish mortality rates can exceed 70% per production cycle in some operations
Lumpfish perform well at lower temperatures than wrasse and are more suitable for Scottish conditions

Welfare Considerations

Cleaner fish welfare represents a significant and largely unaddressed problem in salmon aquaculture. Wild-caught wrasse face the stresses of capture, transport, and introduction into an alien environment containing large predatory salmon. Their specific dietary and shelter needs are poorly met in standard cage conditions. Their high mortality rate reflects welfare failure rather than production efficiency. Setting minimum welfare standards for cleaner fish is urgently needed given the millions used annually.

What You Can Do

Support aquaculture certification schemes that include cleaner fish welfare standards
Advocate for mandatory welfare protocols for cleaner fish in aquaculture licensing
Choose salmon from farms with documented cleaner fish welfare and low mortality data