Salmon Sea Lice Biological Control

Cleaner fish used as biological control for sea lice in salmon aquaculture have their own welfare needs that are often inadequately addressed.

Key Facts

Wrasse and lumpfish are used as cleaner fish in salmon cage aquaculture
Wrasse pick sea lice off salmon without being eaten due to their small size and coloration
The welfare of cleaner fish is increasingly recognized as a significant concern
Lumpfish have a large opercular spine that risks injury in salmon cages
Mortality rates of cleaner fish are extremely high - often 50-90% per year
Many cleaner fish are wild-caught rather than hatchery-raised, depleting wild populations
Ballan wrasse show site fidelity and complex behavior suggesting significant welfare needs
Norway has developed welfare standards for cleaner fish that other salmon producers lack

Welfare Considerations

Cleaner fish placed in salmon cages experience extremely high mortality rates from a combination of factors: salmon aggression, inadequate refuge structures, temperature and salinity stress, disease, and starvation when lice populations are low. These small fish have sensory systems, nervous systems, and behavioral complexity that suggests genuine welfare needs. Their rapid deaths - with 50-90% mortality per deployment - represent massive welfare harm that has received inadequate attention compared to salmon welfare. The welfare of cleaner fish is slowly being addressed through welfare standards in Norway, but the industry globally continues to treat cleaner fish as consumable biological tools rather than animals with welfare requirements.

What You Can Do

Choose salmon from farms with published cleaner fish welfare standards
Advocate for cleaner fish welfare requirements in salmon certification standards
Support research into cleaner fish welfare needs and improvements to their husbandry
Ask seafood companies about their cleaner fish welfare commitments
Reduce consumption of farmed salmon from operations without cleaner fish welfare protocols