Partial success with closed technologies

Trond Rosten, Chair of the CtrlAQUA Board. Photo: Terje Aamodt © Nofima.

RAS has almost become an off-the-shelf product, while semi-closed facilities at sea still have a way to go. According to Chairperson Trond W. Rosten, this is the status after eight years of intense research conducted on fish in closed fish farms in CtrlAQUA.

Written by Reidun Lilleholt Kraugerud for the CtrlAQUA Annual Report 2022.

CtrlAQUA is a Centre for Research-based Innovation in Closed-Containment Aquaculture with 21 partners. The partners have conducted intensive research from 2015 to 2023 to develop closed-containment aquaculture systems into becoming reliable and economically viable technologies for farming salmon up to one kilogram.

The Centre is led by Nofima and Senior Scientist Åsa Espmark, while Trond W. Rosten keeps an overall view of things. As Chairperson of the Board, Rosten has many thoughts about research and development in closed-containment aquaculture technology.

Celebrating long-term collaboration

Rosten describes the process of establishing and being part of a Centre for Research-based Innovation as being part of a growing tree.

“In 2015, the Research Council of Norway formed the trunk by establishing CtrlAQUA SFI. In the consortium, the tree then gained branches as more projects were added and new ideas emerged. The tree has become stronger as research has been verified and adopted by the industry. There are now several interested parties, which gives the tree nutrients to grow further”, says Rosten.

Rosten feels that being part of a strategically important initiative for Norway has been rewarding:

“Long-term collaboration built around clear goals in a fixed constellation has been one of the most positive things for me. When more than 20 partners set common goals, have regular meeting points and work together over eight years, it really impacts the collaboration between research and industry.”

Students are important!

As many as 60 students hold a master’s degree in the Centre and 16 have started their further work after doctoral degrees at the University of Bergen and NTNU. Several of the students have been employed by partners at the Centre and in other aquaculture, health and technology companies, to name just a few.

“The effect of the innovation the students are responsible for is invaluable. Many talented students contribute to spreading knowledge and giving a long-term perspective to research and innovation that we cannot do without.”

There is also a lot of good research being conducted abroad. Partners, such as the Freshwater Institute in the US, have been dedicated allies in CtrlAQUA right from the beginning.

“I think the Norwegian consortium, and especially the supplier industry, has really benefited from this”, says Rosten.

RAS is almost an off-the-shelf product

The CtrlAQUA Centre was formed at a time when the most important thing was to overcome lice problems and escapes. There are still important arguments for extending the time salmon spend away from open sea cages, and in recirculating systems on land or closed facilities at sea. At the same time, the high degree of control over the production process provides a good opportunity to reduce the production time for farmed salmon in net-pen facilities.

RAS is the technology that is most mature out of all the closed technologies, and the research in the Centre has contributed to the technology becoming more accessible and more sophisticated, in Rosten’s opinion.

“We have become much more skilled when it comes to the design and operation criteria than we were eight years ago.”

However, Rosten states that all the improvements come with a price tag:

“It is not getting any cheaper to build or operate closed systems, and it is a 24/7 task that demands a lot from the operators.”

Nevertheless, RAS has been the safest financial investment for fish farmers, and it is now a relatively proven technology. As early as 2021, RAS supplier Pure Salmon Kaldnes reported that almost all new projects for smolt and post-smolt are based on RAS. They also reported that larger facilities, larger tanks and larger fish mean that new challenges are constantly emerging.

About the potential of semi-closed facilities at sea

Rosten points out that for semi-closed facilities at sea, a food fish licence must be used to develop post-smolt technology at the expense of efficient production in open net-pens. This is in contrast to RAS, where the licence has been free of charge.

“This has probably contributed to slowing down the development at sea. Those who have wanted to develop semi-closed post-smolt production at sea have not had the same economic benefits and predictability as those who have built RAS on land. It has also been difficult to obtain or maintain research licences for such technology. This is reflected in the Centre, which has been involved in more modest activity regarding semi-closed facilities at sea compared to RAS”, he says.

There are several suppliers of semi-closed systems at the Centre, such as Aquafarm Equipment, FishGLOBE and FiiZK.

“The semi-closed systems have developed a lot over the eight years, but there are still some uncertainties that mean that there is higher risk associated with working on such facilities compared to both traditional nets and RAS”, says Rosten.

Many of the experts in CtrlAQUA believe that semi-closed facilities at sea will play an important role in the future of salmon farming in Norway. For example, Professor Are Nylund at the University of Bergen has previously stated that the main advantage is that such facilities hardly have any lice problems, and that they have a competitive advantage by being at sea.

Water treatment is much easier than it is on land, while logistics, treatments and cleaning can be more complicated and costly. Knowledge development in CtrlAQUA regarding semi-closed facilities has really increased in the last couple of years, and Rosten is optimistic that it will continue:

“I hope and believe that everyone who uses the technologies is interested in implementing new knowledge, and documenting and validating performance in closed systems on land and at sea. In this way, we can identify new research and development needs. Publishing new research results in peer-reviewed journals is important to drive the knowledge further forward, and I think CtrlAQUA has contributed a great deal to this. We should be proud of that.”

CtrlAQUA has contributed to obtaining much more knowledge about the biology and technology of farming fish in closed-containment systems in the phases where this is relevant. When it comes to fish welfare, the Centre has addressed major issues such as hydrogen sulphide, nephrocalcinosis and smolt quality; knowledge that helps increase fish welfare.

At the same time, there are problems associated with skin and wounds that have not yet been resolved. Freshwater resources are limited, and fish farmers have learned how to produce a lot of food on limited resources in efficient facilities both on land and at sea. Rosten believes this development will continue, and that we will see expansions where resources and expertise already exist – i.e. larger facilities with increased safety and performance.

The previously mentioned tree is thus growing well, and Rosten hopes the development of new and existing production systems will not lose momentum in the years to come. He is also pleased to see that more actors are emerging and that the Norwegian Seafood Research Fund (FHF) is also funding several important research projects that are relevant to the development. Rosten says the CtrlAQUA Board and several of the partners have reflected on whether the Centre for Research-based Innovation collaboration should continue:

“The Centres for Research-based Innovation scheme has worked very well as an instrument in the CtrlAQUA context. If the Research Council of Norway announces a new call for proposals, we will sit down and discuss it and would like to get more people involved in a collaboration”, says Rosten.

Trond W. Rosten is Group Manager for Freshwater and Closed Production Technology at Mowi ASA, and has a long career in research and aquaculture. Mowi is a partner in CtrlAQUA, and Rosten has been chairperson of CtrlAQUA since 2020.

Facts about closed-containment systems

  • In closed-containment systems at sea, most systems are still semi-closed because they do not treat all inlet water or collect waste. Many farm smolt and potentially keep them there until they weigh 500-1000 grams. In practice, they currently work as an intermediate stage for post-smolt weighing between 100–150 grams. The advantages of such closed-containment systems at sea are that they take in a lot of good seawater from the depths where there are less lice, less algae and fewer fish pathogens compared to the surface. A sealed wall separates the sea environment from the fish on the inside of the facility and prevents fish from escaping and lice from entering.
  • Currently, closed facilities on land are primarily used in the production of smolt up to 250 grams, but it has become more common in Norway to expand smolt production up to 500-800 grams. Some fish farmers want to produce salmon up to slaughter size of 4.5 to 5.5 kilograms in such facilities. Such projects are also of great interest abroad, where there are limited natural geographical advantages for producing salmon in net-pen facilities. Land-based facilities often use recirculation technology for water treatment, and up to 99.9 percent of the water is purified and reused multiple times. The effluent therefore contains a higher concentration of nutrients and is less in volume.