Huge Gap Between World Demand For Fish And What Can Be Sustainably Harvested

ScienceDaily 13 Oct 08;

The President of SINTEF Fisheries and Aquaculture, Karl Andreas Almås, crouches over his laptop, opens one of his presentations and finds an illustration. It shows one red curve and one blue one. He then indicates the point where they meet each other, then frowns and says the message he cannot repeat often enough: There is a huge gap between world demand for fish and what we can harvest from the world’s natural stocks. The figures are clear: If we don’t do something about the over fishing, the stocks of wild fish will be dealt a death blow.

At the same time, the world’s population continues to grow – and with it the global demand for food.

“On a global basis today, we have an average annual consumption of 15-16 kilos of fish per person,” says Almås. “If we are going to continue consuming at this rate, we need to double the production of farmed fish within the next 20 years. Doing this in a sustainable manner will be a major challenge.”

Balancing act

As well as expressing his concern, the president is also optimistic. As the head of Europe’s largest research institution for fisheries and aquaculture technology, he knows more than most about the conditions in the sea and how this can be achieved.

According to Almås, there are two main parts to the work towards sustainable aquaculture, but they are closely connected:

One is to develop technology for more selective and gentle capture of species in the sea to enable natural growth in the stocks and only capture the quality we actually want. This must also occur without the fishing fleet using large energy consumption.

The other is to increase the efficiency of the aquaculture sector. The president’s figures show that the difference between fish production in 1980 and that which we will require in 2030 is a full 60 – 70 million tonnes of farmed fish. This means among other things we must stop using fish as feed for farmed fish. Fish caught at sea must be human food. Therefore, we need to find feed alternatives that can be captured lower in the food chain. Plant oils and proteins may be utilised as ingredients for feed in the aquaculture industry, and this is an area some research scientists are working on. Another alternative is to convert natural gas to bio proteins, so-called single-cell proteins.

Last, but by no means least, we need to succeed in finding some new species of farmed fish and develop technology that enables a smarter and more cost-effective production of the fish species we are already farming.

If Almås achieves his visions of technological development and knowledge transfer, there will be few quiet days for he and his colleagues at SINTEF SeaLab at Brattørkaia in Trondheim Harbour. However, they are already well on the way to finding solutions for the challenges.

Trawling down in the food chain

One of the research scientists eager to put fresh aquaculture knowledge into practice is Research Director Håvard Røsvik. Together with product designer and colleague Mads Heide, he is working on the final polish of a new animation. It demonstrates one of the research scientist’s pet projects: a bubble trawler, which until now the world has not seen equal to. Soundtracks featuring the cries of sea gulls, the splashing of waves and the sound of boat motors turn the film clip into a living description of the trawler that utilises air bubbles instead of a net to surface its prey: the 3 mm long, protein-rich Calanus finmarchicus.

“This tiny creature, which has its natural place long down in the food chain, contains large amounts of proteins as well as marine fats,” says Røsvik.

The film shows the boat chugging off on the smooth sea, while releasing air bubbles down into the sea. As Calanus finmarchicus contains many hairs on its tiny body, it attaches itself to the air bubbles in the same manner as a nail attaches itself to a magnet, and floats up to the surface. The tiny creatures are then collected in a fine-mesh cloth and enter the catch chamber with the assistance of a pump system. Seemingly, it is just as simple as it is genial. (Se egen sak. S... red. anm.)

The challenge previously has been to capture a sufficient volume of the little chap. With this trawler, it is likely that large enough volumes can be captured to make it profitable. There is certainly enough to capture: Calculations show there are 300-400 million tonnes in Norwegian waters alone.

“Capturing just one percent of this biomass would cover the requirements for the Norwegian aquaculture industry,” says Røsvik.

The 90 degree effect

Another challenge Røsvik and his colleagues are working on is selective capture: Developing trawler systems that make it possible to catch fish of the correct size without damaging the small fish.

“Trawling accounts for 40 percent of the world’s total fisheries production,” says Røsvik. “As such, improvements to this method of fishing will produce major consequences for the different fish stocks and the areas in which they live.”

A simple, but extremely effective solution to make trawling gentler and more selective has been to turn the trawl net 90 degrees.

“This is one idea that we tested in our flume tank in Hirtshals in Denmark,” says Røsvik. “Scientists knew that fish were often damaged in the codend because turbulence occurs around traditional codends, causing them to swing from side to side.”

However, by turning the meshes in the codend, the SINTEF research scientists utilised a recipe that did not cause turbulence: namely that the meshes in an outstretched position remain as wide open as possible. It yielded results. The cross-section was 12 times greater and the swinging movements were dramatically reduced compared to traditional codends. Further, the meshes remain open when the trawl is stretched. This means that the small fish escape and the fish that are large enough are damaged to a much lesser extent. Energy consumption was also reduced. A large proportion of the trawling fleets fishing whitefish off the coasts of Iceland, Scotland and New Zealand have now adopted this idea.

Cod farming

In the basement at SINTEF SeaLab, Trina Galloway stands bent over a tank of young cod. Galloway is working on areas including the development of new farmed species. She is now studying the result of one of the department’s latest trials: 15 cm long “teenagers” swimming around in the tanks in the name of research. In two years, these will be large cod that fetch a high price at seafood restaurants. But whether they grow up and become saleable, healthy and good fish is not something we can take for granted. It is the result of many years’ research, trial and error and then yet more research.

One of the challenges associated with farming cod has been to find suitable feed for the recently hatched fish larvae. While salmon larvae hatch with a large built-in packed lunch and develop a functional digestive system relatively quickly, cod require specially developed, live plankton, which is 100 percent research-based!

“On the cod’s part, hatching the eggs is not enough,” says the biologist. “We need to have control of the entire life cycle, including the factors that contribute to the fish that hatch growing up. The conditions need to be optimal.”

Ecosystem in the “cod kindergarten”

What appear to the uninitiated like ordinary plastic tanks with small creepy-crawlies swimming around are actually small, but exactly balanced ecosystems. In each tank, phytoplankton, zooplankton and fish larvae are living in perfect harmony, and physical factors such as water flow, temperature and light are precisely matched. At the end of the hall, there is a two metre high white plastic container filled with a gurgling yellowy-green soup. This is the heart of the facility: a bio filter or “live storeroom” containing the optimal bacterial flora for cod babies, and which supplies the facility’s tanks with mature, re-circulated water.

For small, sensitive, young fish, it is particularly important to have stable growing conditions early in their childhood.

“This is the marine fish hatchery of the future,” says Galloway.

From mono to poly

But the future of the aquaculture industry will offer challenges other than good water for the hatcheries and new feed alternatives. Better utilisation of both the fish farming area and the energy in the feed will be important.

“On average, the salmon utilise only 20-25 percent of the energy in the feed for growth,” says Galloway. “The remainder is separated as waste or disappears out of the cages.”

With this in mind, the research scientists have designed a system for three farmed species. The idea is to cultivate species that live in different stages of the food chain in the same place.

“If we succeed with keeping salmon, mussels and kelp in the same system, the feed will be fully utilised because the mussels and kelp eat the feed not consumed by the fish,” explains Galloway.

Operating aquaculture in this way is relatively new in Norway, but not totally uncommon in fish farming counties in the east. SINTEF research scientists will pursue the idea and develop it for the open sea - and it is precisely far out at sea that the fish farms of the future will be located.

Aquaculture off-shore

“If the aquaculture industry is going to grow globally, this must happen at sea,” says Arne Fredheim. “Fish farming in rough and open sea is something we can do well in Norway, and this knowledge is in demand from clients worldwide.”

There are many reasons why the aquaculture sector is aiming for the open sea. The water quality here is better than the limited areas near land and the temperature is more stable – a factor that improves the quality of the fish meat. Moreover, the flow rate increases, and with it the supply of oxygen to the cages.

He is now working to develop fish farms for the open sea. Fredheim is Director of CREATE, a centre for research-based innovation in aquaculture technology and one of the areas of strategic focus for the Research Council of Norway within innovation. He and his research colleagues at NTNU and SINTEF have received NOK 80 million. One of the research scientists’ visions is an advanced fish farm that can “think for itself”. Such fish farms will be able to float to more optimal locations when required and submerge in the sea when exposed to rough weather.

Even though this vision is unlikely to be a reality for at least 10 or 15 years, the technology for fish farms in the open sea is already in place.

“Our part is to view the total, integrated process, from the technological and operational sides through to the biological challenges,” says Fredheim.

Today the research scientists are working on developing such fish farms through different projects. One of the challenges is to find out how long a submergible cage should use on its ascent back to the surface.

“Some fish species can actually get a sort of decompression sickness,” says Fredheim. “Ascending too quickly will, for example, burst a cod’s air bladder. Maybe it is ideal that a cage uses several days to complete the ascent up to the surface.”

Utilising the whole fish

One floor above the laboratory’s “fish kindergarten”, Marit Aursand is sitting at her desk thumbing through a report. The report is about “functional food”, one of the hottest concepts within food technology. Functional food is food that in addition to providing nutrition contains properties beneficial to your health. One such example is food to reduce cholesterol, which is already available on shop shelves. This is a growing market. As Research Director at the Department of Processing Technology, this is an area in which Aursand is particularly interested.

“One of our main challenges is more of what we catch needs to be used as human food, and the parts that cannot be used for food can be used for marine oils, animal feed or health products,” says Aursand.

“Products like this can be added to other food to provide health benefits. Healthy fish oil can, for example, be added to yoghurt. Fish have the potential for 100 percent utilisation. If we manage to develop automation processes to achieve this objective, this can become an important industry for Norway.”

And with Marit Aursand’s vision, along with new solutions for fishing equipment, fishing methods and fish farming on both land and at sea, maybe we can see hope for the new face of the sea?