|
New research from the Centre for Research-based Innovation in Aquaculture Technology (CREATE) in Trondheim has demonstrated that salmon can be farmed in submerged sea cages, which could prove valuable in combating sea lice and algae.
The salmon swim bladder requires an air supply in order to regulate the fish’s buoyancy. Until now, however, no one realised just how seldom salmon need to surface for air.
This need is being quantified by researchers at CREATE, one of 14 Norwegian Centres for Research-based Innovation established four years ago with funding from the Research Council of Norway.
“We kept salmon in completely submerged cages for 17 days. The individuals swam somewhat faster than usual but they did not exhibit stress. We also tested the pain threshold for how long salmon can continuously stay below the surface. It took four months for them to become excessively stressed,” says Dr. Arne Fredheim, Research Manager at CREATE.
The centre’s researchers believe that submerged cages can be used for extended periods – as long as the cages are lifted to the surface at regular intervals to give the fish access to air.
“But more research is needed to adequately determine their threshold limits,” asserts Dr Fredheim.
Using submerged cages is advantageous for avoiding storm damage and resisting invasion by algae and sea lice. There is also growing evidence that submersion may increase the effectiveness of sea lice medicines.
CREATE carries out research and develops technology for the sea-cage phase of “fattening up” production fish for the market.
Should people be 'stimulated' to eat white fish alternatives to cod?
