When We Shift Food Systems, We Shift Impacts: What New Research Reveals About Ocean Protein and Biodiversity

AllWaters Staff
Dec 26, 2025
4 min read

Conversations about sustainable food are becoming more common. Many people now question where their protein comes from and what impact that choice has on the planet. A new peer-reviewed study offers important data that shifts how we should think about these questions.

The research examined what would happen if we stopped relying on marine fisheries for animal protein and replaced it entirely with land-based agriculture. The findings challenge a popular assumption: that eliminating ocean fishing would automatically be better for global biodiversity.

The Numbers

Replacing all animal protein currently sourced from marine capture fisheries would require nearly 5 million square kilometers of additional farmland. To put that in perspective, that area is larger than all the intact rainforest remaining in Brazil.

The extinction risk comparison is stark. For every million tonnes of animal protein produced, agriculture threatens approximately 2.6 times more species than well-managed fisheries do.

Why is this the case? It comes down to how these two systems work fundamentally.

Two Different Approaches to Food Production

Agriculture requires ecosystem transformation. To grow crops or raise livestock on land, we clear natural habitats and replace them with simplified, human-designed systems. This process removes the complex plant and animal communities that existed there. It happens on a massive scale.

Fishing, particularly well-managed fishing, operates differently. It works within existing ecosystem structures rather than replacing them. Well-managed fisheries primarily remove animals from higher trophic levels—the predators and mid-level fish—while leaving the base of the food web, the plants and plankton that support everything else, largely intact.

This distinction matters significantly for biodiversity.

What the Data Actually Shows

A recent documentary suggested that sustainable fishing is impossible. The science suggests otherwise. Many of the world's fish stocks are now managed with clear data and catch limits. These stocks have recovered or remain stable. The benefits are measurable for both fish populations and the marine ecosystems that depend on them.

This does not mean fishing has no impact. It does. The difference is one of degree and mechanism. The question is not whether we should use ocean resources. The question is how we use them and whether we do so with management systems that maintain ecosystem function.

The research reveals that if we simply shift protein production from the ocean to land without addressing overall consumption patterns, we trade one set of environmental impacts for a larger one.

The Policy Implication

Restrictions on ocean access based on environmental concerns need to account for where that protein will come from instead. Without this full accounting, policy may create the opposite of its intended effect.

If the goal is to reduce species extinction risk and protect biodiversity, the data suggests we need to consider the entire food system. Replacing managed fisheries with expanded agriculture in tropical regions—where most new agricultural land is being developed—would likely increase overall biodiversity loss.

This is not an argument against regulation of fisheries. Unsustainable practices exist and need to be managed. It is an argument for science-based decisions that examine full consequences.

What This Means for Ocean Communities

Coastal communities have built livelihoods, traditions, and deep knowledge around fishing. This research underscores something these communities understand intuitively: fishing, when managed responsibly, is a way of using ocean resources that maintains ecological function.

Well-managed fisheries support food security. They support economic activity in coastal regions. They keep communities connected to the ocean in ways that build long-term stewardship.

When we restrict access to fishing based on incomplete information about alternatives, we risk unintended consequences. We risk shifting impacts rather than reducing them. We risk losing the knowledge and incentive structures that support ocean protection.

A Science-Based Path Forward

The data points to a clearer conclusion: protecting ocean biodiversity and supporting responsible fishing are not in opposition. They can work together.

What matters is how fishing is managed. Catch limits based on stock assessments. Gear restrictions that reduce bycatch. Marine spatial planning that balances fishing with other ocean uses. Transparency in data and decision-making.

These tools exist. Many regions use them successfully. The research suggests we should expand and strengthen these approaches rather than abandon fishing altogether.

Dietary choices matter too. Reducing overall meat consumption, including fish, would reduce pressure on all food systems. But if we are relying on animal protein, the data suggests well-managed fisheries should remain part of the solution.

What Comes Next

As policy conversations about marine protection continue, this research provides crucial context. Environmental decisions do not exist in isolation. They create trade-offs. Understanding those trade-offs is how we make choices that actually protect the planet rather than simply moving harm elsewhere.

At All Waters, our work is grounded in this kind of science-based thinking. We believe ocean protection and responsible access are connected, not opposed. We believe coastal communities and ocean users bring essential knowledge to these conversations. We believe data should guide decisions.

This research supports those principles. It gives us evidence that sustainable, well-managed fishing can coexist with healthy oceans. It reminds us that protecting the ocean means understanding how human systems interact with it—and making choices based on complete information, not incomplete narratives.

Based on "Biodiversity Consequences of Replacing Animal Protein From Capture Fisheries With Animal Protein From Agriculture," published in Marine and Coastal Fisheries, 2025.