Comprehensive analysis published in PNAS underscores why the issue is so persistent, and provides updated estimates on the scope and concentration of industrial scale illegal fishing.
Industrial-scale illegal fishing continues to undermine ocean sustainability, coastal livelihoods, and global seafood markets—despite decades of regulation and recent advances in surveillance technology, according to new University of British Columbia (UBC) research.
"Illegal fishing is not a fringe activity, but a systemic feature of the global seafood economy, enabled by weak governance, harmful subsidies, opaque corporate structures, and complex international supply chains," said lead author Dr. Philippe Le Billon, professor at UBC's Department of Geography and School of Public Policy and Global Affairs.
The comprehensive analysis published in the Proceedings of the National Academy of Sciences examines how illegal fishing operates, where it is concentrated, and why it persists. "Illegal fishing remains profitable because the risks are low and the rewards are high," said Dr. Le Billon. "Even as detection improves, enforcement and accountability lag behind—particularly for large industrial fleets operating far from public scrutiny."
A Global Problem with Unequal Impacts
The study reported that industrial-scale illegal and unreported fishing accounts for approximately eight to 15 per cent of global marine wild capture, underpinning an illicit seafood trade worth US$6.2 to 12.2 billion annually. While illegal fishing occurs worldwide, its impacts are highly uneven. Roughly two-thirds of the illicit trade by value originates in West Africa, East Asia, and Southeast Asia — regions where enforcement capacity is often limited and fisheries are central to food security and employment.
At the same time, much of the illegally caught seafood is consumed in wealthier markets in North America, Europe, and East Asia, highlighting stark global inequities. "The environmental and social costs are borne largely by developing coastal states, while the economic benefits flow elsewhere," said Dr. Rashid Sumaila, co-author and professor at UBC's Institute for the Oceans and Fisheries and the School of Public Policy and Global Affairs.
Eliminating Harmful Subsidies Key to Comprehensive Reform
"Effective action against illegal fishing requires coordinated, multi-level responses," said Dr. Sumaila. "Reducing illegal fishing is not just about catching more offenders, it is about fixing the systems that make illegality profitable and legal fishing harder—especially for those who depend on the ocean the most."
Key priorities include eliminating harmful fisheries subsidies, mandating electronic vessel identification, strengthening port state controls, increasing transparency around beneficial ownership, and improving international cooperation. Equally important are policies that protect small-scale and Indigenous fisheries, promote co-management, and align economic incentives with sustainable and legal practices.
As daunting as the challenge of curbing illegal fishing appears, there are some positive signs, the current geopolitical shocks to the global governance system notwithstanding. For example, the WTO rectified an agreement known as Fish 1, to remove certain harmful subsidies in 2025, while working to strengthen this in a follow up agreement known as Fish 2 currently opposed by India, Indonesia, and the US. Also, the High Seas Treaty entered into force on January 17, 2026. Further evidence that the world can collaborate to stop illegal fishing is that, "China has finally become a Party to the Agreement on Port State Measure (PSMA). To turn these hopeful signs to real action on the water, individuals and civil society have to relentlessly push governments and businesses to tackle illegal fishing," adds Dr. Sumaila.
How Illegal Fish Enters Legal Markets
Illegal fishing is sustained by sophisticated laundering mechanisms. At-sea transshipment, fraudulent documentation, species mislabeling, and mixing of illegal and legal catch allow illicit seafood to pass through ports, processors, and retailers undetected. Weak port controls, inconsistent implementation of international agreements, and limited transparency around vessel ownership further enable these practices.
Large distant-water fishing fleets—often supported by fuel and other capacity-enhancing subsidies—are identified as major contributors to illegal fishing. These fleets frequently operate under "flags of convenience," re-register vessels to evade sanctions, and use complex corporate networks to obscure beneficial ownership and avoid penalties
Technology Helps—But Is Not Enough
Satellite tracking, artificial intelligence, and electronic monitoring systems have dramatically improved the detection of suspicious fishing activity. However, the authors caution that technology alone cannot solve the problem. Enforcement remains fragmented, penalties are often too weak to deter violations, and political will is uneven—especially when powerful corporate or geopolitical interests are involved.
Beyond Environmental Damage
Illegal fishing's harms extend far beyond depleted fish stocks. There is "significant economic losses to governments and coastal communities, increased food and nutritional insecurity, and widespread labor abuses aboard fishing vessels," noted Dr. Le Billon. "Tens of thousands of crew members are estimated to face a high risk of forced labour or unsafe working conditions globally, particularly on vessels operating far from oversight."
Illegal fishing is also linked, in certain contexts, to corruption, smuggling, and maritime insecurity, compounding its social and political impacts.
The complex and often opaque character of seafood supply chains allow illegally caught fish to be laundered into global markets through fraudulent documentation, transshipment, and weak monitoring at ports, Dr. Le Billon concluded.
Casting light on the workings of illegal fishing markets was published in Proceedings of the National Academy of Sciences (PNAS).
