The world’s population is expected to increase substantially over the course of the next three decades. Probably the most widely given prediction is a planet comprising 9 billion people by 2050 and many questions have arisen from this forecast, not least how to create sufficient protein for an additional 2 billion people and how to do it in a sustainable manner.
Because farmed fish produce edible yields superior to swine, poultry and ruminants, based on considerably lower feed conversion ratios (FCRs), aquaculture is expected to play an increasingly important role in the provision of high-quality, nutritious protein in the years ahead. While aquaculture products also tend to have a much lower carbon footprint than terrestrial animals – farmed Atlantic salmon, for example, produces around seven times less CO2 emissions than beef and 50 percent less than pork – the industry still needs to become much more energy and resource efficient, according to Solveig van Nes, manager of aquaculture at The Bellona Foundation.
Van Nes told delegates at the recent international conference, “How can green solutions be good for business?” organized by the Norwegian Embassy in London and attended by Erna Solberg, the Norwegian Prime Minister, that the increase in global population has led to a huge rise in energy consumption. Furthermore, since most of the energy comes from fossil fuel use, there has been a significant upsurge in energy-related carbon emissions.
“We have an increasing number of people needing more food, but it is becoming increasingly difficult to produce this food because there’s less and less access to fresh water and arable land,” she said. “What it all comes down to is how to produce more food using less resources and at the same time have less environmental impact. The answer is clear – we have to look much more to the oceans.
“If we look at the Earth, 70 percent of its surface is covered with water. At the same time, only 2 percent of what we eat in energy terms comes from the ocean. It’s a huge mismatch.
“The surface area that we use to produce food is 0.04 percent, meaning that if we were to increase food production from the oceans 20-fold, we would still use less than 1 percent of the surface area of the ocean. We need to reconsider,” she said.
Van Nes stressed that because 90 percent of fish populations were already fully exploited or overexploited, increasing the harvest from wild-capture fisheries was not an option.
“We need to find new ways, and Jacques Cousteau put it best, ‘We must plant the sea and use the sea as farmers.’ I don’t mean fish farming, I mean farming the ocean, which is much more than fish farming,” she said.
What van Nes and Oslo-headquartered Bellona are advocating is to move away from traditional fish farming methods in favor of “a more ecological way of thinking,” through integrated multitrophic aquaculture that, among other things, stores CO2 in biomass.
“In Europe today, we are mostly doing monoculture – culturing carnivorous fish that are high up in the food chain and need to be fed. What we could do and which would also counteract a lot of the negative effects from conventional aquaculture is to produce lower trophic levels like mussels and algae together with these fish.”
The waste produced by the fish in such systems becomes a resource for the other species. Another benefit is an increase in the efficiency of the resource, she said.
“Without using any additional feed, you can harvest a lot more biomass. Put differently, you can produce a lot more without using any extra resources. Also, you can get local renewable feed resources – mussels are an excellent source of fish feed.”
Van Nes also highlighted algae’s ability to capture CO2 in the ocean and to recycle it into a useful biomass, as well as its potential as a biofuel.
“In a carbon picture, it is an excellent biomass to replace fossil fuels. We are just not there yet. But this is the future, algae grow much faster than any terrestrial plant, they don’t need any land area, they don’t need any pesticides or fresh water.”
To establish whether a multitrophic integrated aquaculture system is economically viable, Bellona has initiated a project, called “Ocean Forest,” in partnership with the Leroy Seafood Group. The primary aim of Ocean Forest is to establish new forms of farmed biomass, for use as food, feed, energy and raw materials for industry and agriculture through cooperation with various research and technology communities.
“We all know we should be eating less meat and that harvesting lower down the food chain is a good way of saving a lot of energy. Seafood is also one of the most resource-efficient ways of producing food. But if you are also producing lower trophic species and going lower down in the food chain, you end up with a lower carbon footprint. This is what we are doing with Leroy,” she said.
“To give an idea of how important it is to have low-trophic species. If we were to replace all the cod and salmon eaten in Norway with red meat, we would increase the carbon footprint by 31 million tons, which is almost the complete output of carbon in the country annually.
“It’s not just about how aquaculture can be more economically viable, it’s also about the bigger picture,” said van Nes. “Without the use of carbon capture and bio-energy, the costs of decarbonization will increase by more than 200 percent by 2100. Tomorrow’s aquaculture should therefore combine CO2 capture with the production of food, feed and clean energy.”
