“Closed pen technology was very young at the time we started the Centre, and land-based was very rare in Norway,” says Åsa Maria Espmark, Director of the Centre for Research-Based Innovation in Closed-Containment Aquaculture (CtrlAQUA) at Nofima.
“We wanted to further develop these systems, monitoring fish welfare and working on developing the technology so that closed pens can become a more ‘off-the-shelf’ product.”
Launched in Norway in 2015, the Centre has brought together researchers and industry partners working on long-term experiments to make closed-containment aquaculture systems (CCS) a reliable and economically viable technology.
Over the last eight years, Espmark and her colleagues have trained over 65 postgraduate and doctoral students, many of whom have gone on to work in the industry. Most crucially, the group has carried out essential applied research, working closely with industry partners including salmon farming companies Mowi, Cermaq and Leroy.
The project began, Espmark explains, with one major motivation from both industry and government alike: the problem of sea lice and fish escapes.
“Since at least since 2012, Norway has been facing big challenges with sea lice and fish escapes, and back then there was a great deal of discussion about different methods to either treat or avoid lice.”
Are closed systems a good solution for sea lice?
As far as both biologists and Government is concerned, Espmark explains, prevention is better than cure when it comes to sea lice. Salmon welfare is a key concern. One promising preventative method is the use of closed containment systems.
Closed systems can be land-based where water is recycled, or sea-based, in which large floating tanks receive clean water from depth, Espmark explains. Researchers at CtrlAQUA have been investigating both approaches.
“Closed systems enable you to keep the fish away from the open sea for a longer period of time, including smolt that is adapted to life in seawater,” says Espmark. That means less exposure both to sea lice and to wild fish populations.
“We aimed for post smolt of up to 1K on land or in semi closed systems, with the goal of keeping the fish away from the open ocean for longer.”
“We wanted to look at the performance, welfare, and health of the fish, to see how they cope in these contained environments, and also further develop the technologies used.”
Welfare is good in closed pens, but more research is needed
Espmark notes that over the past eight years there has been “tremendous” development in closed-pen technology. Some are already commercially available, with even some “off-the-shelf” products available to buy. Others are still prototypes in need of further development.
“Since closed pen systems were in such an early stage of development when we started the centre, we’ve worked a lot on monitoring fish welfare and performance in them.”
Espmark explains that the team followed several generations of salmon within the same system, as well as comparing these with reference pens.
“We have concluded that overall, the welfare in these systems is good,” she says. However, more work needs to be done.
“We still need more knowledge. In these systems, you don’t get sea lice, but you can have other organisms coming in that can cause disease. For example, how can we stop bacteria from getting into these systems?”
“Technology is needed both to treat the water that comes in and to treat the outlets. This has become a necessity not only for the farmers. We expect that, in time, it will be a request from the government. This will enable closed pens to be used in areas where traditional fish farming is not suitable for different reasons.”
Location and depth are the key to success for closed pens
“What we have seen from our research, and what we say to the users is that with closed pen, you need to go quite deep to pump up water in order to avoid picking up bacteria and parasites.”
However, Espmark notes, key to the success of any closed-pen operation is its geographical location.
“Some areas are very good, and some areas are more challenging. There is not one quick fix,” she says.
Espmark says the team mapped the effects of different depths on the fish in closed pens. “For instance, we were interested in how deep you need to go to prevent wound bacteria getting into the system. That can depend on the season. It can depend on the geography. It’s not something where you can create one protocol which is valid for everybody.”
RAS gives more control but needs expertise to get it right
Recirculating aquaculture systems (RAS) presents a set of different challenges, says Espmark. In contrast to sea-based flow-through systems that are “more dependent on the external world, on where the water is coming from,” the key benefit of RAS is control over water quality, temperature and other parameters, she explains.
At least, that’s the theory. “You have the possibility to control the environment, but running a RAS unit requires a lot of knowledge,” she points out.
“What kind of water quality is the best for the fish? Which kind of environmental factors are best? How fast should the water velocity be? How much carbon dioxide can you have in the water before it stresses the fish or impairs growth?”
“These issues are very important for the industry. Throughout the project we’ve been working to enable the industry with knowledge about what is good water quality in a RAS system and how should you treat the fish there to maintain health and welfare, and avoid diseases.”
“For the RAS producers, it’s mainly about water quality. It’s how to treat the biofilter, and how to make a robust fish that also copes well after you put them into sea.”
Long-term experiments yield crucial knowledge needed by industry
One huge advantage of the CtrlAQUA project, Espmark says, was its mandate to run long-term experiments, following the fish from smolt to harvest, and evaluating the success of the different closed pen technologies used.
“We have run experiments that started here in on land with small fish and that followed them all the way to slaughter. That takes 1.5 to 2 years, from start to end, and these are normally very expensive experiments. But we’ve had some external funding that enabled us to run these longer-term studies, and test different protocols. For example, in RAS, we looked at the light regime, as well as salinity, and the size of the fish.”
“We wanted to see what kind of treatment on land gives the best output in the end. These are experiments that the industry really applauds.”
“The reason why we haven’t done experiments like this in the past is because they are too expensive, but it is almost the only way to get the answers. If you follow the fish only for a few months after they are put into the sea, a lot can happen after that. If you have good growth with one protocol on land, this does not necessarily result in the best growth at the end. It is very useful knowledge.”
Close collaboration with aquaculture industry partners is key
The project involved collaboration with 21 external partners, 14 of which came from industry, in fish farming, technology development and biotechnology.
“Part of our work has been to disseminate information in a way our industry partners can easily use it,” Espmark says. In addition to academic papers, the Centre is active in other forms of knowledge transfer to make results easily accessible. Information about the Centre’s findings has been channelled to industry through seminars and meetings, as well as factsheets, online presentations and internal deliverables.
“The collaboration we’ve had with industry partners has been very fruitful,” Espmark says.
“Norway has a long tradition of close collaboration between R&D and industry. But if you ask the farmers and user partners about the benefits of being a part of our Centre, I think most of them will say that the networking is very important.”
“They’ve been able to talk to colleagues from other companies as well as our researchers. We’ve kept an approach where we can talk freely about our projects and results. We also receive feedback from the industry, about how they are doing and what their challenges are.”
Espmark explains the Centre’s research agenda has been informed by input from user partners in the industry.
“We’ve been lucky as we have had the freedom to make research plans year-on-year. These are also based on input from user partners. We’ve asked them what kind of experiments they would like to see us run, or what kind of knowledge is lacking within the industry, for instance, on water quality treatment or management.”
Increasing biological knowledge will help farmers
Espmark points out that the Centre has also been working on biological research and disease prevention.
“This has included ground-breaking research on gene expression for fish skin health, looking at how to protect against disease and infection.”
“I think it’s becoming even more clear and important that this is not just basic research, but it can be applied and used by the industry. There is a whole battery of indicators to tell if a fish is robust, and ready to put in the sea. “
“You can use gene expression, you can use fish behaviour, you can use different colouration in the skin. The more objective indicators you have, the more certain you can be about how the fish will cope after you transfer them to sea.”
Better regulations needed to enable closed pen development in Norway
“I really believe in these systems. They are the future in some areas where traditional net pens are not suitable. Sometimes that is because of sea lice, but it can also be because of proximity to wild fish populations.”
Espmark explains that government regulations are needed to continue developing closed-pen operations in Norway.
“Lack of regulation has grown to be a real challenge for some of our partners. We have addressed some of the regulatory challenges, even though this was not our initial aim”.
“These systems are very expensive to install, and you need a concession from the government, which also costs money. You also have challenges when you want to move the fish out of the pens.”
Espmark says the Norwegian government is currently working on regulations for both closed-pen and land-based operations. “I’m positive that a solution will come,” she adds.
A “diverse” future predicted for Norwegian aquaculture
Espmark says that she and her colleagues are now thinking beyond CtrlAQUA to look at other production systems.
“We’ve been working with RAS and semi-closed systems, but there are other production systems we haven’t looked at in CtrlAQUA that will also be part of the whole Norwegian aquaculture industry.”
“We see a future with a greater diversification of how and where to produce the fish, and what species to use. Now the focus is of course on salmon, and it will be so in the future. But there are other species that are also possible to grow in Norwegian aquaculture.”
Diversification of location is likely, Espmark predicts, with closed pen systems offering the chance to redevelop disused industrial sites.
“Sites need to have access to water. Some of them will be with flow through, some with RAS, but there are many possibilities.”
“Still much work to be done” before offshore is viable
Offshore aquaculture is also on the horizon, notes Espmark, pointing out CtrlAQUA has a sister project on offshore, SINTEF’s SFI Exposed.
“I think offshore will grow over time. My understanding is that offshore has come further with the technology development and not as much on the fish welfare side. So, much more work needs to be done.”
“Most of the offshore projects so far are flow-through systems. They are not in the in the wildest open sea and it remains to be seen how they cope with really bad weather. Fish must be delivered there and taken out of there. People need to work there occasionally, so the health and safety aspect is very important.”
The aquaculture industry needs more long-term research collaborations
“I hope we will have a stable, sustainable aquaculture growth in Norway – a responsible growth with different production systems.”
“The tight collaboration we’ve had with our industry partners has created a need for more projects like this,” Espmark adds.
“A big advantage with a project like CtrlAQUA is that you can work with an issue for such a long time. You can get deeper into the problems and develop solutions, and that is something the industry needs.”
CtrlAQUA is a centre for research-based innovation (SFI) doing research on closed-containment aquaculture systems. The main goal is to develop technological and biological innovations that will make closed systems a reliable and economically viable technology.
Nofima AS is the host institution of CtrlAQUA, collaborating with several partners from research, the supplier industry and salmon farming companies. Read more about the CtrlAQUA Partners.