Blue Innovation: How to fill fishing nets without emptying the seas

Entrepreneurs, investors, and some environmentalists are beginning to back new forms of mariculture as a potential long-term solution to the depletion of wild fish stocks and the world's increasing demand for protein.

Mariculture is a burgeoning branch of seawater farming that involves cultivating fish, crustaceans, molluscs and aquatic plants in the ocean. Many see it as the next frontier in sustainable food production.

“It is a vastly under-exploited food source; often an after-thought,” Pearl Dykstra, deputy chair of the European Commission’s Scientific Advice Mechanism (SAM), told a Science|Business event on Blue Innovation held in Brussels on February 27.

Dykstra is part of a six member SAM panel that has been looking at how more food and biomass can be obtained from the oceans in a sustainable way.

According the data collected by SAM, mariculture could add an extra 300 to 400 million metric tonnes of biomass for food or animal feedstock each year. That is a three to fourfold increase on current yields, and would help compensate for declining catches of wild fish.

Expanding mariculture would also “hopefully avoid putting more land under agriculture,” said Ricardo Serrão Santos, Portuguese member of the European Parliament and an expert on marine biodiversity and ocean ecosystems. 

“We mostly eat conventional fish from the top trophic layer, and pay much less attention to everything underneath,” said Poul Holm, professor of environmental history at Trinity College Dublin and member of the Horizon 2020-funded Science Advice for Policy by European Academies (SAPEA) consortium. “We shouldn’t disregard the opportunities when they’re there. Really, the way in which we deal with the ocean today is unenlightened and involves poor management.”

Given the growth in the food sector, investors are looking for new opportunities, and sustainable, large-scale mariculture is beginning to take shape in Europe.

Marina Gebert, head of the marine biotechnology department at the German Fraunhofer Research Institution for Marine Biotechnology and Cell Technology, is using macro-algae to develop lemonade and beer, and undersised mussels for a paste for spreading on bread. “We are seeing a growing trend to work with organic, local ingredients. Ours come from the Baltic Sea,” said Gebert. “We are in the testing phase of our beer but if the reaction is positive, the craft beer brewery that we are working with is willing to commercialise.”

Interest in aquaculture and mariculture is growing as global fish production approaches its sustainable limit.

Quotas have helped to rein in out-of-control fishing in Europe, but elsewhere activity has long passed the point at which most fish stocks are sustainable. Some 90 percent of the world’s fisheries are fully exploited or “facing collapse", according to the United Nations Food and Agriculture Organisation.

“We need to give the big stocks time to recover,” said Serrão Santos. “Recovered stocks will need small pelagic and mesopelagic fish, and krill to feed on. Any approach concerning targeting these resources should have taken that into scope.”

However, participants at the meeting also cautioned that policymakers should not rush to support a burgeoning industry without knowing the full environmental implications, such as the possible eutrophication of water and the need for some wild fish to feed on smaller animals and plants.

“We probably still lack a complete understanding of how mariculture will affect the whole ocean web,” said Lisandro Benedetti-Cecchi, vice rector for European and international research at the University of Pisa. EU research can certainly help “fill the knowledge gap,” said Sigi Gruber, head of marine resources at the Commission’s DG Research and Innovation.

Politicians also need to consider the many sea activities, from shipping and seismic surveys to undersea drilling and offshore wind farming, jostling for coastal space, the conference heard.

Boosting investment in the sector requires harmonised rules for licences, which presently vary widely between jurisdictions, according to the SAM report.

A switch to consuming smaller sea animals would also entail a “broader shift in public perception” and eating habits, said Holm.

Felix Leinemann, European Commission head of unit for blue economy sectors, aquaculture and maritime spatial planning, referenced a promotion campaign in Japan to interest consumers in fish other than salmon, tuna and shrimp that would be retrieved as so-called bycatch.

New tastes take time to evolve, but even then, “seaweed is definitely not the next potato,” said Pi Nyvall Collen, R&D manager at Olmix, a French agrifood company.

War on plastic

Sustainable fishing and mariculture must go hand in hand with a drive to tackle plastic pollution, the meeting heard.

At current rates, in 2050 there will be more plastic than fish in the ocean, by weight.

Growing populations and wealth in countries including China, a major source of plastic pollution, is having an outsize impact on the globe’s oceans.

“The issue around plastics in the sea is scary, particularly in Asia,” said Serrão Santos. “We need plastics, but we need to correct the way we use them.”

The EU is mulling various ways to tackle the problem, including new taxes to reduce single use plastic in packaging.

A recent report for the European Commission by Mariana Mazzucato, director of University College London's Institute for Innovation and Public Purpose, suggested there should be an EU research mission to reduce the amount of plastics entering the seas by 90 per cent.

The target is too high, but the general effort is laudable, many people at the meeting agreed.  

“Most animals will likely have some plastic in their guts,” said Erik van Sebille, an oceanographer and climate scientist at Utrecht University. He has a grant from the European Research Council to trace the distribution of plastics around the world and says the problem is much bigger than most people realise, he said.

“Around five million metric tonnes of plastic enter the oceans every year,” said van Sebille. “But only 1 per cent floats at the surface of the ocean. The rest is either on coastlines, on the seafloor or inside organisms.”