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FISH FARMING TECHNOLOGY #2 Vónin case study: Tough environment calls for tough cages If they work in the Faroes, then they’ll stand up to practically anything. That’s the thinking behind Vónin’s aquaculture cages.

The Faroe Islands are a fantastic place to rear salmon, with perfect water temperatures and fast-flowing currents of crystal-clear water – but it’s still one of the toughest environments in the world to anchor cages and the advantages come as part of the north Atlantic weather that brings a string of storms that batter the islands every winter. In fact, producing its own cages is a relatively new venture for Vónin. Adding its own cages to its product range means that Vónin is now able to supply complete salmon cage packages.

The plastic brackets

The brackets that hold the tubes of the cage rings together presented a few challenges and Vónin used computeraided design to identify weak points and achieve the optimum strength in the HDPE100 injection moulded brackets. “These had to be as strong as possible, with no compromises,” Vónin’s Bogi Nón commented. “The neck of the bracket tends to be the weak point where failures can occur, so it was important to get these right.”

Bakkafrost orders cages with distance bars

The first of the new Vónin cages, which were supplied to Faroese salmon producer Bakkafrost have had a full year in the firing line of those winter storms and passed that particular test with flying colours after a process of making some minor adjustments to ensure optimum performance. Bakkafrost ordered eight cages, but also specified a design using steel distance bars between the brackets, allowing the cage tube itself to move freely inside the brackets – making the cages effectively self-cleaning, but with the downside of a

40 | April 2017 - International Aquafeed

APR 2017 - International Aquafeed magazine