Wrasse Welfare as Cleaner Fish in Salmon Farming: 2025

Wild-caught and farmed wrasse species are used as cleaner fish in salmon aquaculture but face significant welfare challenges in sea cage environments.

Key Facts

Several wrasse species including ballan and goldsinny are used in salmon sea cages
Wild-caught wrasse are harvested from inshore reefs, raising sustainability concerns
Farmed wrasse production from hatcheries is growing to reduce wild capture
Wrasse require refuges within salmon cages as they are not adapted to open water
High mortality rates in salmon cages represent a serious welfare concern

Welfare Considerations

Wrasse placed in salmon sea cages face severe welfare challenges. As reef-associated species, they are profoundly mismatched to open-water cage environments. Without refuges, they cannot rest or shelter from salmon harassment. Strong currents in exposed sites exceed wrasse swimming capacity, causing chronic exhaustion. Cold winter temperatures below approximately 8 degrees Celsius suppress wrasse activity and effectiveness. Mortality rates in salmon cages for wrasse can exceed 50 percent in some systems. The Scottish Salmon Producers Organisation has developed welfare standards for wrasse but implementation and auditing vary. The ethical justification for wrasse use requires that welfare is demonstrably better than chemical alternative.

What You Can Do

Choose salmon from producers with documented wrasse welfare monitoring and low mortality rates
Advocate for mandatory refuge provision and mortality reporting for cleaner fish in salmon farms
Support research into alternative biological and non-biological sea lice control methods
Ask retailers about cleaner fish welfare standards at salmon farms they source from