Norway taps sustainable marine resources in response to fish farming boom

Aquaculture is growing faster than any other major food production sector.

According to the UN Food and Agriculture Organization (FAO), the industry has observed 5.8% annual growth rate since 2010, and in 2016, aquaculture production increased by four million tonnes compared to 2015 figures.

“By 2030, the world will eat 20% more fish – or 30 million tonnes live equivalent – than in 2016,” ​noted the agency. “Aquaculture production that year is projected to reach 109 million tonnes, a growth rate of 37% over 2016.”​

Such a dramatic global increase is placing a significant strain on feed resources. Whereas 20-30 years ago, proteins and oils in fish feed were exclusively sourced from fish meal and fish oil, today these sources are limited.

As a result, in Norway, where farmed fish accounts for approximately 70% of fish exports, researchers are working to develop sustainable alternatives to fish oil and meal.

Sports nutrition for fish?​

Volumes of pelagic fish, such as anchovies and sardines traditionally used to feed farmed fish, are on the decline, according to UiT The Arctic University of Norway’s Ragnar Ludvig Olsen. This can be, in part, attributed to an increase in direct human consumption of these fish species.

Increasingly, processing waste – the by-products of fish harvesting – is being used to feed farmed fish all over the world. Depending on the species, fish processing can produce 30-70% by-products that are ‘not fit’ for human consumption, Olsen explained. Often, this is because “there is no tradition for eating those products”, ​the deputy head of UiT’s Norwegian School of Fisheries elaborated.

From a sustainability standpoint, using by-products in feed is superior to farming pelagic fish for the same purpose. It means industry avoids wasting resources, we were told during a visit to the university in Tromsø: “We are recycling and using [these by-products] indirectly for food.”​

Norwegian researchers are working to take this production one step further, to ensure farmed fish receive high quality, nutritious feed. “You can make protein hydrolysates and omega-3 rich oils from these wild species and farmed fish – it’s the simplest and least expensive way there is,” ​he explained.

And research to date has achieved ‘good results’, Olsen continued, likening this specialist feed to sports nutrition for humans. “You get the same effects in fish farms as in fitness food [for athletes],” ​we were told. “I sometimes say that we could compete with those producing whey, because in addition to peptides and free amino acids, it also contains some long chain omega-3 fatty acids – so you get a double effect.” ​

Fermenter-grown microalgae​

Obtaining ‘significantly more’ food and biomass sustainably from the ocean, however, relies on harvesting food at a lower trophic level than we do currently, the researcher suggested.

Venturing down the food chain in the ocean – which he reminded us covers 70% of the earth’s surface – reveals a variety of zooplankton and microalgae in extraordinarily large volumes.

Such microalgae are the ‘original producers’ of long-chain omega-3 fatty acids found in fish, he explained. “So they are not produced by fish, but by the microalgae [they eat].” ​

In order to harness phytoplankton – which currently makes up approximately 95% of the ocean’s biological production – the researchers are working with industry to develop mass cultivation strategies. Having collected phytoplankton species in Norway’s arctic waters, the organisms are now being cultivated in fermenter tanks.

Phytoplankton requires carbon dioxide, iron, nitrogen and phosphorous to grow. By partnering with companies in the steel and iron industry, the researchers hope to divert industry’s fumes into the fermenter tanks, thereby limiting the amount of carbon dioxide emitted into the atmosphere.

So how could these cultivated phytoplankton benefit today’s food systems? “The easiest product to obtain [from this production] would be feed for farmed fish,” ​the scientist suggested. While food for human consumption may be a ‘long-term goal’, Olsen said the acknowledged strategy is to “get something that you can sell ASAP. And that is, of course, feed. It is very attractive because of the expanding fish farming industry all over the world".​