Fisheries Ecology and Aquaculture

Ruth Berit Hjellum

Behaviour of cleaner fish in salmon cages

My name is Ruth Berit Hjellum, and I am doing my master thesis on the behaviour of cleaner fish in salmon cages. The project was performed from August to October 2014 at the research station of IMR at Austevoll. Three species of wrasse (leppefisk); ballan wrasse (berggylt), corkwing wrasse (grøngylt), goldsinny wrasse (bergnebb), as well as lumpfish (rognkjeks), were placed in different combinations into 30 salmon cages (5x5m). The methods used for monitoring the situation were: Counting salmon lice weekly, observing behaviour using under-water cameras, and registering the location of the cleaner fish in the cage using antennae that were reading the PIT-tags that had been inserted into each cleaner fish. The goal is to see how the different combinations of cleaner fish species affect eachother, their well-being in the cage and their lice-eating efficiency.