Future proofing fish farming

Report interviews Kåre Olav Krogenes, General Manager of Viewpoint Seafarm,

and Odd Stensland, Production Manager of Nova Sea AS, a leading Norwegian fish

farmer about two revolutionary offshore fish farming concepts under test at MARIN.

Can you tell readers about your companies?

Kåre: “I am actually a mechanical engineer and have had a mixed career in both the oil sector and in fish farming. For the oil and gas industry I worked in different locations across the globe and was often introducing new, patented technology. I had the idea of perhaps transferring some of this offshore

“Nova Sea is the majority owner of Sundsfjord Smolt which has a capacity of 13 million smolt (young salmon) per year and it has an additional facility, Helgeland Smolt, with authorisation for 8 million smolt. The company’s packing facility at its headquarters on the tiny island of Lovund has a capacity of around 350 tonnes a day, and per annum some 50,000 tonnes of salmon are produced.”

What are the current practices for fish farming in Norway, and the problems associated with these?

Kåre: “Currently most of the fish farms are in the fjords and all this intense activity is causing problems with outbreaks of sea lice at some farms, which can damage the fish or even kill them. The government recognises that the fish farming sector is important and wants the industry to grow, but this has to be done in a sustainable way.”

“Two years ago, the government introduced a ‘traffic light’ system for its 13 fish farm zones, with eight in the so-called green zone, three in amber and two in the red zone (in the west where many farms are). Increased production capacity is allowed in the green zone or if the sea farmers can satisfy the government’s strict criteria, which urges companies to bring new technology to the market to help combat the problem of sea lice and to move the farms further away from the fjords. If fish farms want to grow, they have to be in a green zone, but by developing new technology, they can get access to new areas offshore.

“More than 135 companies applied for a new technology licence to be able to grow their business but only a handful – seven or eight - got the go - ahead and the first has started operations.”

What is the Viewpoint Seafarm concept?

Kåre: “The Viewpoint Seafarm concept is first of all, an offshore solution, which deploys a combination of an open and closed system. Given my background, I came up with the idea of using a former drilling rig, which given the drop in the oil prices, was obtainable at a lower price. There are many synergies. For example, the rig is the traditional fish farm ring shape and we can make use of quite a lot of its equipment such as the cranes, mooring system, accommodation unit, pump and lifting equipment. All we then need is the net and fishing system.

“The concept will enable us to farm 3,100 salmon in six to eight cages with a circumference of 120-160 m. Overall, if Viewpoint Seafarm obtains all of the 20

Two offshore concepts tested in MARIN’s basin

Viewpoint Seafarm concept

Kare Olav Krogenes Odd Stensland

technology to the fish farming industry. Around two years ago I established Viewpoint Seafarm when the Norwegian government challenged the fish farming industry to come up with new technology, which would enable the sector to grow in a sustainable way. Viewpoint Seafarm knew we needed a solid partner in the fish farming sector so we teamed up with Nova Sea.”

Odd: “Nova Sea is one of the largest producers of Atlantic farmed salmon in Northern Norway, where decades ago they thought it was impossible to farm salmon. Our fish farms are spread down the coast of Helgeland, from Vega in the south to Gildeskål in the north and are located in fjords and out at sea. We have 39 licenses, and we operate in an area that covers around 10% of the entire coast of Norway.

licences we have applied for, the whole farm would produce 15,600 tonnes of salmon.

“This is a complete sea farm with all of the systems integrated into it. Outer steel barriers protect employees, the fish and the construction from external forces and the farm includes an integrated processing and feeding system, service and maintenance system. The farm also has living quarters and a control room for employees and scientists.”

It is not a traditional fish farm design?

Kåre: “Viewpoint Seafarm is not based on a traditional cage system but a ‘flexible cassette’ with a double barrier system. This makes it easier to move fish from one station to the other, and it is much less stressful for the fish when they have to be treated. There are walkways inside the

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Spider cage concept

main structure to reduce the risks during maintenance and crucially, there are no moving parts inside the cages eliminating the risk of ruining the nets. Additionally, the facility is self-sufficient producing its own electricity.”

Odd: “Because it is for offshore sea farming, this eliminates the risk of contamination in the fjords and it is a long distance from any other sea farms, which reduces the risk of disease. We have spent a lot of time considering how the systems should be aligned and integrated. By putting out large smolts with an average size of 600+ grams, the production of fish up to 5 kg can go on for 10 months a year. In the remaining two months we clean the equipment and introduce a new generation of fish. It is hoped we will be able to start operations in 2020.”

Viewpoint Seafarm is exploring the potential of a second, fish farming concept?

Kåre: “Yes, this is for a smaller fish farm called the spider cage. We are applying for four licences for this technology. This centres on an outer steel ring with another ring inside with a heave compensation system between the two rings. The inner ring contains the net, which because it is more static, reduces potential mechanical problems with the net.”

Odd: “The spider cage also reduces the likelihood of sea lice as the structure is 12 m underwater and lice lie on the surface, unless there is some rough weather. This is a very good way of protecting the fish and it makes its own power, not requiring a generator on land, making it energy neutral. There is also a big reduction in the amount of supply/support boats that need to visit the farm.”

Were both concepts tested at MARIN?

Kåre: “Yes, we have a very good cooperation with MARIN; the experts here have helped us find out about the pros and cons of each system and which points we need to adjust. We are recommending MARIN to the other Norwegian fish farmers developing these new systems! The model tests showed that the Viewpoint Seafarm concept is amazingly stable, even in sea states with Hs 11m, and that is when the net structures and cages are attached. In October, we started tests on the spider cage and again, we had very good input from MARIN and the results were in line with our own tests.

“As well as this scale testing of the net also took place, firstly with a towing testing campaign. This enabled MARIN to

analyse the loads on the net, plus any additional loads caused by marine growth.

“Both systems are as steady as can be! And I think this is an important statement to the government. We have shown that we have done the testing and taken the next step, these are not just concepts.”

How do these initiatives help the development of the sustainable fish farming industry of the future?

Kåre: “Part of the government programme is that this technology should be shared, so other fish farmers can buy the design. And when considering that only 2.5% of food worldwide comes from the sea and the growing population, it is evident we need sustainable fish farms.

Viewpoint Seafarm and the Spider Cage concepts are both innovative, offshore fish farm solutions based on semisubmersible technology. Viewpoint Seafarm comprises a hub, which is (semi) supporting four floating net cages interconnected through a dedicated hinge system. Each floater has a projected area (seen from above) of approximately 50 m x 35 m. In the tests it has been demonstrated that the cages provide the required stability to survive conditions up to Hs 11 m.

The Spider Cage is a completely different concept designed to keep sea lice out of the farm. A dedicated barrier, with a

diameter of approximately 100 m, has been constructed shielding the actual fish cage from heavy sea conditions and lice. Tests have been performed up to sea states of 11 m with and without current, where general motions, accelerations, loads and sloshing have been assessed.

In order to simulate the behaviour of the concepts accurately it is important to truly understand the scaling laws for the net structures in relation to waves and current. An important factor is to be aware of the flow within the fish cage to assure high standards for the welfare of the fish. Hence the flow measured at scale should

accurately represent the flow at full scale. In close cooperation with ICON SYSTEMS and Viewpoint Seafarm, we have performed dedicated tests to assure that scaling related to the net structure and the flow in/around the structure are representative and well understood. Both concepts have been tested successfully and the findings of the test campaign have been recorded for the successful continuation of the development of the fish farm designs.

Rene Lindeboom

r.lindeboom@marin.nl

“These concepts will also be interesting in other parts of the world where farming is taking place - Chile, Scotland, Alaska, Canada, China… It is a good opportunity for other countries to have fish farms further offshore, away from the coast. In Norway this started as a small market but in 10 years it is a global product. We are taking the lead like we did in the oil and gas market.”

Odd: “Who knows where we will be in 20 years’ time? Two young teachers started Nova Sea in 1972 in North Norway when everybody was saying it wasn’t possible to farm fish that far north. It was too cold, too dark. They flew 1200 young fish in plastic bags over to the island of Lovund in a seaplane and only 174 survived to full maturity. Many people said this was proof it

would be a disaster, but our founder thought this was actually a success and the start of something. We now produce 50,000 tonnes a year today and we handle some 12.5 million smolts per annum. The feeding barge supplies 400 tonnes of feed. So, if this is in 40 years, imagine what we will see in the next 20 with developments like these!”

Two concepts based on semisubmersible technology

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