The quiet success story of global tuna fisheries. How science-based fisheries management is helping tuna stocks recover.
By Dr. Victor Restrepo, Vice President, Science and Chair of the Scientific Advisory Committee, International Seafood Sustainability Foundation.
Public discussions about the ocean often focus on decline. Headlines about overfishing, biodiversity loss, and climate change paint a picture of marine ecosystems under relentless pressure. Those concerns are real. But they are not the entire story.
In the case of global tuna fisheries, the latest analysis points to a quieter, often overlooked success.
According to the most recent Status of the Stocks report from the International Seafood Sustainability Foundation (ISSF), 97% of the global commercial tuna catch now comes from stocks at healthy abundance levels, and nearly all tuna stocks are not experiencing overfishing. For fisheries that operate across multiple oceans and involve dozens of fishing nations, this is a remarkable outcome.
More Than a Decade of Science-driven Progress
This progress has unfolded gradually over more than a decade. Since ISSF began tracking these indicators annually, the share of global tuna catch coming from healthy stocks has steadily increased as fisheries management organisations adopted stronger science-based measures.
This progress did not happen overnight, and it certainly did not happen by accident.
The global tuna fishery is one of the most complex food systems in the world. Twenty-three major stocks of tuna are regularly assessed by scientists and managed through Regional Fisheries Management Organisations (RFMOs). These bodies bring together coastal states and distant-water fishing nations to cooperatively set catch limits, establish conservation measures, and monitor fishing activity across international waters.
Over the past two decades, a steady accumulation of science-based reforms has helped improve the health of many tuna stocks. Stock assessments have become more sophisticated, giving managers better information about population trends and fishing pressure. Increasingly, fisheries managers are adopting harvest strategies—pre-agreed management procedures that automatically adjust catch limits in response to changes in stock status. These approaches are robust to multiple forms of uncertainty and help ensure that management decisions stay aligned with scientific advice.
Equally important has been a transformation in transparency and accountability within tuna fisheries.
Observer programmes and electronic monitoring systems have expanded across many fleets. Vessel registries and traceability tools allow industry and fisheries managers to track fishing activity with far greater clarity than was possible even a decade ago. These advances help ensure that management measures are followed and that sustainability commitments translate into real-world practices at sea.
Markets have played a role as well. Seafood companies, retailers, and consumers increasingly expect evidence that seafood products come from responsibly managed fisheries. This demand has encouraged supply chains to support stronger management measures and improved monitoring. The result is a system in which science, governance, and market incentives increasingly reinforce one another.
None of this means the work is finished. Some tuna stocks continue to face management challenges, particularly in regions where harvest strategies have not been fully implemented and where no agreements have been found on allocation of catches. Excess fishing capacity is also a challenge because, if unmanaged, it would certainly lead to overfishing of many stocks. Maintaining progress will require continued vigilance and cooperation from fisheries managers.
Keeping the Momentum Going
At the same time, a new set of challenges is emerging. Climate change is altering ocean conditions and, in some cases, shifting the distribution of tuna populations. These changes will require fisheries management systems to become more adaptive and responsive to new scientific information.
The lesson we have learned is that progress is possible when decision-makers listen to science and when institutions are designed to act on that information.
Too often, global fisheries are portrayed only as cautionary tales. The story of tuna demonstrates something equally important: large-scale marine resources can recover and remain productive when they are managed responsibly. And that success depends on a simple but powerful principle. Science must guide the rules that govern how we fish.
Global tuna fisheries feed millions of people and support the livelihoods of coastal communities around the world. Ensuring their long-term sustainability will require continued cooperation among governments, scientists, fishing companies, and seafood markets.
The encouraging news is that we already know what works. The challenge now is to keep applying those lessons. Because in ocean conservation, as in many areas of environmental policy, the hardest challenge is not always discovering the science. It is consistently acting on it.
The story of global tuna fisheries shows that when science leads and cooperation follows, sustainable fisheries are not just possible—they are achievable at scale.
Image: Dr. Victor Restrepo, credit: ISSF
