Symbio

The salmon louse is the most common parasite on farmed salmon, and one of the biggest challenges for the aquaculture industry. Cleaner fish, which from nature's perspective are designed to feed on such parasites, are used in cages to feed on lice from farmed fish. 

Under the right conditions, this represents an effective form of biological delousing that can prevent chemicals entering the environment and saves a lot of money for the farmer. 

Cleaner fish is a group of fish consisting of Lumpfish and different species of Wrasse.  Amongst other things, they feed on the sea lice that live on farmed fish. In common with salmon lice, the cleaner fish also live freely in nature. Lice-eating species are now caught and farmed on a large scale to control salmon lice in a chemical-free, biological manner. 

Lumpfish and ballan wrasse are the most common species. Biological delousing with cleaner fish is a forward-looking method and represents a continuous, preventive treatment for salmon louse. After a slow start with the use of wild-caught wrasse, today we see that the farming of cleaner fish is the most popular measure to combat salmon lice. 

In recent years, we have seen an increase in the farming of ballan wrasse, which can be a better choice than Lumpfish for some farmers.  

In the past, it was not common that cleaner fish in cages were fed maintenance feeds. This practice has evolved because research has shown that cleaner fish with inadequate access to essential nutrients are less healthy and less effective in their role. 

The salmon louse is a small crustacean from the copepod family. It is a parasite that lives freely in seawater in all areas of the sea in the northern hemisphere. It attaches itself to the fish as a copepodite and remains stuck there until it can move and change position on the fish.