Cleaner Fish Welfare in Salmon Aquaculture: Lumpfish and Wrasse

Cleaner fish used as biological control for salmon sea lice represent an important welfare advance over chemical treatments, but their own welfare needs are often inadequately met.

Key Facts

Lumpfish and various wrasse species are used as biological sea lice control in salmon farms
Cleaner fish consume sea lice directly from salmon, reducing lice load without chemical treatment
Lumpfish are produced in large numbers and deployed at high densities in salmon cages
Cleaner fish mortality rates are very high — often 50-80% per deployment — raising significant welfare concerns
Wrasse species including corkwing and goldsinny wrasse are wild-caught in the UK for Scottish salmon farms
Welfare standards for cleaner fish are substantially less developed than for salmon, despite their sentience

Welfare Considerations

Cleaner fish represent a welfare irony: they are deployed to improve salmon welfare by reducing sea lice burden, but are themselves managed with minimal attention to their own welfare needs. Lumpfish in particular experience very high mortality from inadequate nutrition, salmon aggression, and the stressful cage environment. Their welfare needs for shelter, appropriate feeding, and protection from salmon aggression are rarely met in commercial deployment. Wild-caught wrasse removed from their natural habitat and deployed in intensive salmon cages represent a different welfare harm — removing animals from their ecological context for instrumental use. The welfare case for biological lice control over chemical treatment is real and supported by evidence; but realizing its welfare benefits requires also meeting the welfare needs of the cleaner fish themselves.

What You Can Do

Advocate for welfare standards for cleaner fish to be incorporated into salmon aquaculture certification
Support research into cleaner fish welfare needs that informs better deployment management
Ask salmon retailers about whether their suppliers use cleaner fish and whether welfare standards apply
Support development of welfare-positive lice control methods that reduce dependence on high-mortality cleaner fish deployment