IUU Fishing

What it is

IUU fishing groups three distinct failure modes in global fisheries governance. Illegal fishing covers vessels violating national laws or regional management rules, whether by operating without a licence, catching protected species, or working in closed areas or seasons. Unreported fishing covers catches not disclosed to national authorities or regional fisheries bodies, distorting the stock assessments that set sustainable quotas. Unregulated fishing covers vessels flying flags of states outside any management regime, operating beyond any formal oversight structure.

Together, the three categories account for an estimated 11 to 26 million tonnes of catch per year, roughly one in five wild-caught fish sold commercially, per FAO estimates. Global economic losses run to US$10 to US$23 billion annually, with some analyses reaching US$50 billion when supply-chain multiplier effects are included.

The two core actor groups are flag states that either cannot or will not police their fleets, and coastal states that bear the cost of stock depletion. China operates the world's largest distant-water fishing fleet, estimated at roughly 16,000 vessels as of early 2026. Flags of convenience from Caribbean and Pacific micro-states let vessels evade national enforcement. Regional Fisheries Management Organizations (RFMOs) hold formal governance jurisdiction, including the WCPFC (Western and Central Pacific), ICCAT (Atlantic tuna), and CCAMLR (Antarctic), but enforcement capacity is uneven across these bodies.

History

The term IUU fishing was coined at a 1997 CCAMLR meeting, prompted by surging Patagonian toothfish poaching in Antarctic waters. The FAO codified the concept through its International Plan of Action to Prevent, Deter and Eliminate IUU Fishing (IPOA-IUU), adopted by the FAO Committee on Fisheries in March 2001 as a voluntary instrument under the Code of Conduct for Responsible Fisheries.

The Port State Measures Agreement (PSMA), negotiated under the FAO, entered into force in June 2016 as the first binding international treaty specifically targeting IUU fishing. It requires parties to deny port access to vessels suspected of IUU activities and to share vessel intelligence through a global record system. As of early 2026, 72 states plus the European Union are parties. The EU complemented PSMA with its own IUU Regulation, in force since 2010, which requires catch certification for all fish entering EU markets, creating a paper trail investigators use to trace laundering.

Current state

Enforcement is increasingly surveillance-led rather than at-sea. Global Fishing Watch, launched in 2016 with support from Google and the Pew Charitable Trusts, tracks AIS transmissions from hundreds of thousands of vessels and publishes risk scores built on 11 behavioural indicators, including AIS-off gaps, extended voyages, and social-network proximity to blacklisted vessels. The scores are decision-support tools for port inspectors and coast guards prioritizing checks, not legal determinations of guilt.

The geopolitical dimension sharpened in 2026. China's distant-water fleet drew a January 2026 US congressional report that branded it a "unified geopolitical weapon." Vessels in the fleet routinely disable AIS near the exclusive economic zones of Argentina, Ecuador, and Peru, depleting squid stocks those coastal economies depend on. Japan responded in January 2026 with a US$1.9 million UNODC grant for surveillance drones and patrol boats across four South American coasts. For the full congressional report and fleet detail, see 美国国会委员会将中国远洋渔业船队定性为'地缘政治武器'，巡逻力度加大.

Relationships

IUU fishing operates alongside forced labour at sea, money laundering, and document fraud, making it a fisheries-crime nexus rather than a standalone regulatory problem. UNODC categorizes the associated crimes: vessel identity spoofing, bribery of port officials, tax evasion on undeclared catch, and at-sea transhipment networks that launder illegal product into legal supply chains. A single carrier vessel can collect catch from dozens of fishing boats in international waters, then deliver it to a port as a legitimately documented consignment. Human-trafficking investigators frequently find the same vessel networks moving both fish and people.

What to watch

• Whether the PSMA's party count grows and enforcement bite deepens as the EU ties market access to compliance.
• Global Fishing Watch's expanded IUU-risk dataset release, targeted for late 2026, which is expected to sharpen port-state inspection targeting.
• US Treasury and EU import sanctions escalating against specific companies and flag states.
• Whether South American coastal states make arrests against the Chinese squid fleet or rely on surveillance alone.