Closed-containment proves effective
A large scale trial of a new closed-containment system has met with promising results, with zero lice recorded in the first month of deployment.
Called ‘Salmon Home No 1’, the pilot system was stocked with 60,000 smolts by Nekton Havbruk in mid-November after several months of tests.
“All in all, it is going terrific,” Nekton’s CEO Rune Iversen tells kyst.no. “The fish regained their appetites quickly after being stocked and have grown satisfactorily. There are also no lice to see, despite weekly counts.”
The plan is to grow the smolts in the system until the spring, before completing the cycle in standard net pen cages.
“The fish will be stocked into in ordinary cages in March/April, by which time we expect they will be 350-400 grams,” he adds.
The closed cage is the first of its kind, and was designed and built in collaboration between Nekton, Fish Farming Innovation and Betonmast.
According to Iversen the fish are looking very good, and are being monitored closely by both Nofima and fish health company Åkerblå. Nofima also takes frequent measurements of water quality in the tank.
“Since this is new technology requires extra surveillance on fish welfare, we use Iris Jensen, a vet from Åkerblå. We use a so-called SWIM model that contains individual-based welfare indicators – picking out poor performers, spinal deformations, smoltification, maturation, the degree of fin and skin damage, and the number of sea lice,” explains Iversen.
The fish are also tested for PD every month and gill scores are conducted weekly.
The pilot tank is 1000 m3 and has a capacity of 60,000 smolt up to 500 grams. If the pilot phase is successful, Fish Farming Innovation and Betonmast can rapidly scale up the design to 5000 m3.
The oxygen level is maintained to an automatically selected level, morts are collected in the bottom and can easily be picked up without pumping, and faeces are constantly accumulated in the bottom and taken out of the tank.
