Mariculture of tomorrow: with swift and careful action, the ocean can be farmed sustainably | UCSB

The world population is expected to exceed 10 billion people in the lifetime of our grandchildren. That’s a lot of people to feed.

Traditional means of land-based meat production are facing strict limits to expansion and the challenges posed by climate change, making the ocean an important source of protein as we strive to feed three billion more people than ‘today.

In a paper published in the journal Nature, an international collaboration of researchers takes an in-depth look at the potential of a warming ocean to satisfy the growing global appetite.

“Climate change will test the ability of the ocean to meet the seafood needs of a growing population,” said Christopher Free, a researcher at the UC Santa Barbara Bren School of Environmental Science & Management and main author of the article. “However, the ocean could produce more food than today with swift and ambitious action.”

Sustaining the food supply

Currently providing only 17% of the world’s protein supply, most of which is wild-caught, the ocean holds great potential to help meet the global demand for meat, which is expected to continue to grow, especially developing countries get richer.

But it is also subject to global greenhouse gas emissions, which lead to effects such as warming and acidification, phenomena that are expected to reduce the ocean’s ability to meet the seafood needs of a growing population.

“Warming waters are changing where fish can live, what prey they can eat, and how well they can survive,” Free said. “Fishermen and fisheries managers must adapt to these changes.”

Fisheries can maintain or increase their yields by adapting their practices to changes in the productivity and location of their fish stocks, the researchers said. However, these reforms alone, while necessary, will be insufficient to meet future demand. Fish and shellfish farms will be essential to fill this gap.

“The expansion of sustainable ocean aquaculture could build on fisheries reforms to increase the availability of healthy, sustainable seafood for our growing population,” said Halley Froehlich, assistant professor at UCSB and co – author of the article.

According to the study, the expansion of mariculture is likely to be limited by consumer demand or the availability of food ingredients from wild catches, rather than climate change.

With the appropriate selection of species and location, for example, researchers found that “the availability of an area for the profitable mariculture of finfish was insensitive to changes in temperature, oxygenation, and salinity.”

Moreover, since food production, by its nature, generates environmental impacts, the sustainable expansion of mariculture must be carried out with caution.

“This will require better governance to ensure best practices that minimize impacts on ocean ecosystems and encourage equitable access to this growing industry,” said Willow Battista, senior executive at the Environmental Defense Fund and co-author of the item.

What this governance sweet spot will look like will vary by location. In highly regulated geographies such as the United States, mariculture regulations may need to be better defined to allow sustainable mariculture to develop. In weakly regulated regions, such as China or Thailand, standards will need to be maintained to avoid inefficiencies and ecosystem degradation.

Regions with little or no historical mariculture production, such as in many African countries, which are expected to be hardest hit by climate change, will need to invest in training and infrastructure.

More efficient agriculture

Effective and efficient mariculture operations also have the advantage of requiring only a small amount of space; according to the study, typically 3% or less of a country’s exclusive economic zone is needed to meet consumer demand, according to the researchers’ calculations.

“The small space required for mariculture leaves ample room for careful planning to minimize impacts on other ocean industries,” said Steve Gaines, dean of the Bren School and co-author of the paper. With careful coordination, mariculture operations can be set up in a way that does not compete with fishing, coastal tourism and shipping, among other ocean industries.

In fact, its efficiency is one of the main advantages of mariculture: it has a lower greenhouse gas footprint and lower water and land demands than many land-based meat sources. And with improvements in fish feeding, breeding and rearing, there is scope to further increase yield to meet consumer demand.

Shifting food production to the ocean could not only satisfy the growing global appetite for meat, but also free up land needed for land-based agriculture, researchers say.

“Shifts in consumer preferences away from terrestrial meat could reduce the environmental impacts of global food systems,” Froehlich said. With an increase in production, prices should come down, allowing access to local, sustainable and nutritious food.

Producing food from the ocean for future populations will undoubtedly require a concerted global effort. But nowhere is this more urgent than in tropical developing countries, places where climate-induced loss of productivity, coupled with population growth, is putting a strain on food security.

“Developing tropical countries will suffer the greatest losses in fisheries catches and therefore could be priorities for investment in expanding ocean aquaculture,” said Reniel Cabral, lecturer at James Cook University and co-author of the study.

The research in this article was also conducted by Erin O’Reilly at the Bren School; Elena Ojea from CIM-University of Vigo; James E. Palardy at the Pew Charitable Trusts; Jorge García Molinos at Hokkaido University; Katherine J. Siegel at UC Berkeley; Ragnar Arnason at the University of Iceland; Marie Antonette Juinio-Meñez from the University of the Philippines; Katharina Fabricius of the Australian Institute of Marine Science; and Carol Turley at the Plymouth Marine Laboratory.

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