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Research gets credit for more secure fish-farms

Escapes of fish have long been a problem for the aquaculture industry. But now, improvements in technology and systematic research have drastically reduced the number of escapes.

Aqualine AS recently invited all its partners to MARINTEK's Ocean Laboratory, where they could follow tests of a model of the company's Midgard sea-cage system at close range. Aqualine was awarded employer organisation NHO's Innovation Prize for the system in 2015, and has already sold 350 sea-cages, most of them to the Norwegian market. Midgard was designed and patented by Aqualine and tested and verified by MARINTEK, and is believed to be the industry's first escape-proof sea-cage system.

Reliable system

"Midgard is an extremely reliable system for our clients. If the use it correctly, it is completely escape-proof. It is just the same as with petroleum installations. They need to be used correctly if they are to be safe," says Aqualine's technical director Martin Søreide.

"How important has MARINTEK been for the development of this new technology?"
"Without MARINTEK, we would not have been able to develop Midgard. It's as simple as that. I believe that MARINTEK possesses the highest level of expertise in model testing and analysis in marine technology of anywhere in the world. We obtain all of the correct results of the calculations for structures of this sort from model tests rather than from analytical programmes. I use all the answers we get in this way to design our systems," says Søreide.

MARINTEK's scientists also agree that Midgard is a robust system In the Ocean Laboratory, the sea-cage was exposed to powerful currents and high waves in the course of systematic model tests.

"The model tests enabled us to study interactions between the mooring chains and the net, and we realised how bad these are. Now, we have developed a better concept in which we attach the bottom ring directly to the net," says MARINTEK research manager Vegard Øgård Aksnes.

Ten-fold rise in production

Fish escapes have been one of the most important challenges facing the aquaculture industry. But the problem is now much less serious than it used to be. The Norwegian Directorate of Fisheries believes that this is largely due to the fact that the industry has put more into research and development.
"There are fewer escapes nowadays, based on what we find in the rivers, than there were in the 80s, in spite of the fact that production is ten times as high as it was about 30 years ago. This is largely down to research and development. However, more R & D is still needed before these products can be brought into use," says Geir Martin Kvamme, senior consultant at the Directorate of Fisheries.

Want to learn from Norway

People from all over the world came to the meeting in Trondheim to learn about the technology used by an industry that lies at the global cutting edge.

"It is very impressive to see how much research has been put into this design. Our industry is relatively young in comparison with Norway's. In Australia, we would have bought first a framework and then a net, which might or might not have been suitable. The system is then built up bit by bit. So it is very instructive for us to visit MARINTEK and just as importantly, AquaNor ," says Jonny Deuge of Petuna Aquaculture in Australia. John Power agrees with Deuge.

"It was very exciting to experience a model test and observe the technology at close hand. Quite incredible," says Power, of Green Harvest in Ireland.