Salmon has become a largely consumed seafood in Europe, the US and Japan, with 75% of it coming from the rapidly growing farming industry. Yet the industry faces big environmental challenges linked to the feed resources used in salmon farming. This involves adapting to more sustainable ways of feeding, shifting from large amounts of fish meal and fish oil to more plant-based alternatives.
However, current plant-based alternatives, once thought to be the most environmental friendly source of feed, have been criticised for their environmental impact. Because we wanted to dive deeper into this topic we interviewed conservation expert Anne Leifsdatter Grønlund from the Rainforest Foundation Norway (RFN), and Norwegian University of Life Sciences professor Margareth Øverland.
Limited resources: a need for change
One thing is certain, feeding our salmon with other marine animals is not the greenest solution we have at our disposal today. According to Anne Leifsdatter Grønlund the discussion about sustainability often forgets to include feed. “Several years ago it was the reason the fish industry started using soy,” she said. “It was to replace marine ingredients which were being over-fished. For many years soy has been applauded as the perfect solution to tackle over-fishing.”
What we did not seem to anticipate, however, is the pressure that an increased demand in soy would be adding on forests. And that demand is expected to grow even more in the future, as she explains: “Now, we do see that the Brazilian soy industry faces huge challenges in terms of deforestation of different ecosystems in South America, and environmental and social problems related to the extensive use of pesticides and conflicts with indigenous populations and small farmers.”
“The Norwegian salmon industry is the largest in the world and has a big responsibility,” added Leifsdatter Grønlund. “The ambition of the Norwegian government is to increase the production of farmed fish five-fold by 2050. Marine resources are already reaching the limit – you can’t take more marine resources to produce fish feed. If you multiply the amount of farmed fish produced then you’d have to multiply by more than five times the amount of plant-based resources in the feed.”
The promise of new plant-based alternatives
Today, we know that current plant-based alternatives to fish meal are directly adding pressure on the world’s farmlands. What if we were rethinking the way animal feed was produced and came up with greener alternatives? This is what Margareth Øverland, professor at the Norwegian University of Life Sciences and Center Director of Foods of Norway, has been working on. “During the last 10 years I’ve been working on developing microbial ingredients from second and third generation sugars,” she said. “Either from Norwegian spruce trees or from macroalgae. We’re fermenting these sugars together with nitrogen and other nutrients to produce microbial ingredients such as yeast, and are able to replace other ingredients in the Atlantic salmon’s diet, such as soy protein concentrates, fish meal, and other protein sources. With this method you can produce yeast with up to 50 to 55% protein.”
While many types of seaweeds exist Øverland’s research focuses on one particular type. “We work with brown seaweed and specifically sugar kelp, which is the common name. They grow well on ropes and you get large amounts of seaweed biomass that you can harvest. They’re rich in sugars, and these are what we call third generation sugars that can be used to ferment yeast.”
The benefits of macroalgae or seaweed seem endless as Øverland explains: “These seaweeds are cultivated in the sea and have a positive impact on the environment. They recycle nutrients like nitrogen and phosphorous that are lost from the aquaculture sites. The seaweed downstream can recapture these nutrients that are lost. They also have a positive influence on CO2 levels.” Macroalgae grow very well on Norway’s long coastlines. After being deployed in February they produced huge amounts of biomass which can be harvested three to four months later in May or June. It is a culture which doesn’t rely on any input such as fertilisers, making it environmentally sustainable.
Getting producers on board for a more sustainable future
With a rising demand for salmon projected by the industry there is a need to shift towards more responsible sources of feed. Today’s technology allows us to reach high protein feed made from macroalgae and as Margareth Øverland explained, seaweeds are the fastest growing plants we have in the world. “They produce an enormous amount of biomass per hectare,” she said. “You cannot compare it to the land based plants, it’s quite substantial. And we are now developing the technology to cultivate them more efficiently. As Foods of Norway, and together with Seaweed Energy Solutions, we now have the technology to cultivate and harvest them in a sustainable way.“
“The seaweed are the fastest growing plants we have in the world. They produce an enormous amount of biomass per hectare.”
While the technology is in place the biggest obstacle to making these alternatives available to salmon farmers remains the market. If alternatives aren’t made available to farmers then their volume on the market will likely remain low. As Øverland points out, “What companies need is a market channel – it could be directed to salmon feed or regular animal feed. Once they have the market they will scale up the production.”
With such alternatives along with the emergence of other less resource-dependent sources of feed like insects, it is likely that the footprint of the salmon industry on global fish stocks and rainforests will decrease. While everything seems to point us towards a more sustainable future it is now left to the industry players to work together to meet the consumers’ growing demand for more responsible products.