From left: Tor Kristian Stevik, Oxyshield™ project manager at Plany, Bjørnar Aga Larsen, Mowi operations manager, Øyvind Butz, Mowi operations technician, Hans Kristian Tveito, Mowi deputy operations manager, Idun Unneland, apprentice aquaculture, Mowi, Jan Erik Klepp, CEO, Plany, Ronny Pedersen, Plany service manager, Roy Atle Igland, Mowi operations technician, and John Bertil Aakernes, AGA project manager.
The main purpose of Oxyshield™ is to optimise the environment for farmed fish by reducing lice infestations and improving oxygen conditions. Research results show that a clear relationship exists between oxygen saturation in the water and fish growth as well as feed utilisation. Low oxygen values yield reduced growth and poor take-up of feed.
Oxyshield™ prevents lice infestations with a physical barrier at the same time as supplying oxygen provides a controlled environment for good fish welfare and efficient production.
“A lice skirt is the best single measure for preventing lice infestations,” says Plany CEO Jan Erik Våge Klepp. “Its drawback is a reduced oxygen level in the cages. We and AGA have overcome this by combining a lice skirt with the addition of pure oxygen.”
Bjørnar Aga Larsen, operations manager at Mowi’s Gulestø fish farm. Mowi’s operations technician Roy Atle Igland and deputy operations manager Hans Kristian Tveito can be seen in the background.
“I have faith in the concept, and that it can help to optimise the cage environment, improve fish welfare and enhance growth conditions”, says Bjørnar Aga Larsen, operations manager at Mowi’s Gulestø fish farm.
“If it can help us to keep the lice skirts in place as long as possible, it’s all to the good.”, says Bjørnar Aga Larsen. Results so far show that Oxyshield™ can be used throughout the production cycle and thereby help to reduce delousings. That not only saves costs for the fish farmer, but also reduces stress on the fish.
Ove Nybø, operations technician at the Mowi facility Gulestø.
Ove Nybø is an operations technician at the Mowi facility, and monitors developments at the various cage levels via the control-room monitors on the feed raft. In addition to fish activity, he also checks that feed is eaten before it reaches the bottom of the cage, which indicates whether fish appetites are good and how much they consume.
“Combined with the amount of feed we provide, this shows how much the fish eat and the weight they put on,” he explains. “I believe oxygen has a positive effect on the fish. When its level in the cage is good, we use more feed and the fish eat better. “
“We see a gain with feeding,” says Hans Kristian Tveito, deputy operations manager at the Mowi farm, who reports that they supply more feed to the cages which are oxygenated.
AGA’s SOLVOX® DropIn being tested at Mowi’s Gulestø facility.
AGA’s SOLVOX® DropIn solution plays a significant role in the Oxyshield™ concept because it allows oxygen to be added effectively to the water through a low-pressure solution involving microbubbles.
“Small improvements in growth can yield substantial financial gains with the volumes we’re talking about here. Imagine a farm with eight cages and the volume of fish in each of these. Increasing annual growth by just one per cent while cutting mortality by the same percentage through fewer delousings could add up to a substantial rise in revenue and a larger bottom line, and not least to better fish health”, says Tor Kristian Stevik, Plany’s project manager for Oxyshield™. He has worked on the test project at Gulestø for more than three years.
Service manager Ronny Pedersen at Plany (left), and AGA project manager John Bertil Aakernes. Behind them is the AGA plant which supplies oxygen to the Gulestø fish farm.
“This is the best documented and most extensive development project with precision oxygenation of fish-farm cages to date,” reports project manager John Bertil Aakernes at AGA.
“With Oxyshield™ and precision oxygenation, the fish farmer won’t be wasting resources,” says Aakernes. “In other words, the microbubbles don’t get carried away sideways by the current or rise to the air and pop, but make the oxygen available to the fish before reaching the surface.”