The Rise and Fall of Cleaner Fish in Norwegian Salmon Farms

At first, it seemed like a brilliant solution to the problem of salmon lice in Norwegian salmon farms, but then it turned into a near-disaster.

^{Text: Lena Scherman}

When cleaner fish first began to be introduced into salmon farming cages, the practice was hailed as both environmentally friendly and effective. It was believed that the problem of salmon lice could be solved immediately without the use of chemicals or the shock of hot-and-cold water treatments. However, a new study that synthesizes other research shows that the approach was both too hasty and based on insufficient knowledge of animal welfare to be successful in the long run.

Since 1998, over half a billion cleaner fish have been released into salmon cages in Norway. And everything indicates that it has been bad for the cleaner fish the whole time.

The use of cleaner fish in salmon farms peaked in 2019; since then, usage has declined. And one of the main reasons for this is that the cleaner fish are suffering and, to a large extent, dying in the cages. Salmon farmers have tried to change conditions in the farms without much success because the cleaner fish simply have not been able to adapt to life in offshore cages.

^{Cover photo: Catfish in a water tank. Photo: © Tim Dempster}

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