Aquaculture Welfare

Aquaculture: Cleaner Fish Wrasse Welfare

Wrasse are used as biological sea lice control in salmon farming, but their welfare needs are poorly understood and often inadequately met.

Key Facts

Six wrasse species are used as cleaner fish in Atlantic salmon cage aquaculture
Ballan wrasse are the preferred species but are slow-growing, limiting supply
Wild-caught wrasse supplement hatchery-produced cleaner fish in most farms
Wrasse mortality in production is very high, with many farms losing most wrasse per cycle
Basic welfare requirements including refuges, substrate, and appropriate temperature are poorly defined

Welfare Considerations

Wrasse welfare in salmon aquaculture is among the most neglected in the sector. Wild-caught animals from complex natural habitats are placed in bare cages alongside much larger salmon, without refuges from predation or access to natural foraging substrate. The high mortality indicates severe welfare compromise. Minimum standards including refuges, substrate, and monitoring are urgently needed before cleaner fish use can be considered welfare-acceptable.

What You Can Do

Support campaigns for welfare standards to apply to all fish used in aquaculture including cleaner fish
Advocate for reduction in wild-caught wrasse and development of hatchery alternatives
Choose salmon certified from programmes requiring cleaner fish welfare provisions
Support research into wrasse welfare requirements and non-fish alternatives
Raise awareness that cleaner fish welfare is a significant blind spot in salmon certification