Good feed and the right environment are key for lumpfish to thrive at work, say researchers from the Norwegian institute Nofima.
Lumpfish are cleaner fish used to fight salmon lice in aquaculture. The Rensvel project aims to find ways of gauging a cleaner fish’s welfare and what it needs to stay healthy. Access to food is important as lumpfish are not strong swimmers and need to rest frequently. They do this by attaching themselves to the tank wall using a ventral suction plate.
“Because lumpfish like to sit on the tank wall and are not fast swimmers, feed needs to fall down near the tank walls. Most commercial farms use dispensers located in the centre of large tanks, which may be too far away for young lumpfish,” said senior scientist at Nofima, Ingrid Lein.
Aggressive bullies
Lumpfish that grow rapidly become aggressive and bully smaller fish. The fish are therefore usually graded by size before being transferred to pens in the sea. The Rensvel project has shown that ungraded lumpfish can live close to their neighbours without any bullying provided enough feed is available. Pellet size is also important.
Lumpfish like clean, well-oxygenated, fast-moving water and to be homed in tanks that provide enough space for all the fish to rest. Being sociable and thriving in groups, crowding is not a problem in itself, as long as the fish get enough food, can find a place to rest and have good water quality.
Nofima has been running the project in collaboration with Nord University, the Norwegian Institute of Marine Research, the Norwegian University of Life Sciences, and the Norwegian University of Science and Technology. The Rensvel project is financed by the Norwegian Seafood Research Fund.
