Boosting seafood production while protecting biodiversity

The world’s appetite for seafood is growing, and the industry is racing to keep up.

A new study suggests that farming seafood from the ocean – known as mariculture – could be expanded to feed more people while reducing harm to marine biodiversity at the same time. However, success depends on careful planning.

The researchers found that the locations and ways in which mariculture is expanded will determine whether it helps or harms the environment.

The findings, published in the journal Nature Ecology & Evolution, highlight both the risks and opportunities of growing this industry.

The science of sustainable mariculture

The study was led by Deqiang Ma, who conducted the research as a postdoctoral scholar at the University of Michigan.

“We can achieve this sustainable mariculture development,” said Ma. “With strategic planning, we can achieve the goal of conserving marine species while meeting the global demand for the expansion of mariculture.”

Mariculture is a type of aquaculture focused on farming saltwater seafood, such as fish and shellfish. In 2020, it contributed about 20% of the seafood consumed globally, providing a critical source of protein for billions of people.

As the demand for seafood production increases, mariculture is expanding rapidly. To understand its impact, Ma and an international team of researchers developed a model to analyze the potential effects of mariculture growth on over 20,000 marine species.

The future of seafood production

The team’s model created a baseline for mariculture’s current impact and simulated how it could change by 2050 under different scenarios.

The researchers also factored in two climate change models – RCP 4.5 and RCP 8.5 – which assume varying levels of warming and greenhouse gas emissions.

In the best-case scenario, where new farms are built in areas with the least environmental impact, seafood production could soar.

“Bivalve production could increase by 2.36-fold and finfish could increase by 1.82-fold compared to current production – projections of what is needed to meet global demand – but the global mariculture impacts would decrease by up to 30.5% under the best-case scenario,” Ma said.

However, the worst-case scenario painted a starkly different picture. If new farms are built in the most ecologically sensitive areas, the damage to marine biodiversity could be more than four times worse than if farms were placed randomly.

The importance of smart expansion

This study highlights the need for thoughtful planning, said senior study author Neil Carter, an associate professor at the University of Michigan.

“It is critically important to leverage the growing insights across disciplines, whether it’s climate change science or economics or marine production,” Carter said. “All these different facets had to come together from other sources in order to make these forecasts.”

The research team included experts from the University of Washington, the University of Freiburg in Germany, Hokkaido University in Japan, and the University of California, Santa Barbara.

Their collaborative effort highlights the complexity of mariculture expansion and the need for coordinated decision-making.

Expanding seafood farming

Large-scale studies like this come with challenges, noted co-author Benjamin Halpern, a professor at UCSB. “But I’ve done this kind of work a lot in my career, and the payoffs can be enormous.”

“The cross-disciplinary nature of the questions that can be addressed and the ability to look at them for every patch of ocean in the world makes the research much more relevant and impactful to society and the scientific community.”

The researchers emphasize that this study is just the beginning. More data and refined models will be needed to fine-tune sustainable mariculture strategies for the future.

Best approach varies by region

One key takeaway is that there is no universal solution. The best approach varies by region. What works in the South Pacific may not be ideal for coastal Europe.

Additionally, even the best-case scenario has trade-offs. In all scenarios examined, mariculture expansion negatively impacted some marine mammals, such as whales, seals, and sea lions.

Understanding these trade-offs is essential for policymakers who must balance food security with conservation goals.

“With these insights, we can see that it’s not a foregone conclusion that the expansion of an industry is always going to have a proportionally negative impact on the environment,” Carter said.

“So the next part of this is getting policymakers and communities to interact with each other to figure out how we can actually implement some of these ideas to reduce those impacts and to prioritize marine biodiversity.”

The full study was published in the journal Nature Ecology & Evolution.

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