At-sea transshipment sits at a critical point in the global seafood supply chain, where strong oversight helps support sustainable fisheries management, supply chain transparency, and accountability across oceans. It can also support efficient fishing operations. However, because transshipment activities often occur far from shore and across multiple jurisdictions, weak monitoring and regulation can undermine responsible fisheries management and create opportunities for illegal, unreported, and unregulated (IUU) fishing activities.
ISSF 2026-02: Benchmarking Tuna RFMO At-Sea Transshipment Measures Against the 2022 FAO Voluntary Guides for Transshipment examines how the world’s five tuna Regional Fisheries Management Organizations (RFMOs) align with the FAO Guidelines for Transshipment — the first global framework specifically developed to support effective transshipment governance. Throughout ISSF’s 17-year history, we have studied RFMO transshipment rules and outcomes — and advocated for more effective RFMO transshipment policies in tuna fishing.
Our new report benchmarks the at-sea transshipment measures of CCSBT, IATTC, IOTC and WCPFC against the FAO Guidelines and identifies practical opportunities to strengthen implementation over time. While our analysis found that no tuna RFMO has yet fully implemented the Guidelines, all have already established important foundations for making future progress.
In fact, all tuna RFMOs already instituted many of the key elements for good management: Vessel authorization systems, observer programs, vessel monitoring systems (VMS), data collection, verification frameworks, and follow-up procedures exist in various forms.
The report’s recommendations are intended to help strengthen, harmonize, and enhance these systems to reduce the likelihood of IUU fishing activities and of products of IUU activities flowing into global markets.
Why Coordination Among RFMOs Matters
Carrier vessels and longline fishing fleets routinely move across RFMO boundaries, sometimes operating under multiple regulatory systems within a single fishing season. That creates a practical challenge: Even strong measures in one region can be undermined if information, standards, or monitoring systems in other regions do not meet the same benchmarks, or if information is not shared across RFMOs. In many cases, RFMOs do collect similar information, but formal mechanisms for sharing data, vessel histories, and compliance information remain limited and are often complicated by a lack of standardized data collection formats.
Some encouraging models exist, however, and greater coordination is underway. CCSBT has formal arrangements with three other tuna RFMOs to share observer and transshipment information. ICCAT and WCPFC both have established procedures for sharing transshipment data between them.
Building on Existing Strengths
Our analysis highlights the substantial progress RFMOs have made:
- ICCAT has the most comprehensive overall framework for managing at-sea transshipment, including broad VMS requirements and prohibitions on vessels without IMO numbers from participating in transshipment activities.
- CCSBT achieved the highest overall implementation rate against the FAO Guidelines, supported by its Catch Documentation Scheme, which creates strong traceability and verification capacities, and its data-sharing frameworks.
- IATTC stood out in several core areas, including vessel authorization requirements and its regional observer coverage program.
- IOTC has strong carrier vessel authorization frameworks and a Regional Observer Programme covering carrier vessels.
- WCPFC demonstrated strength in transparency mechanisms and data-sharing, including mechanisms that support access to data for monitoring purposes.
Our transshipment best practices “snapshot” provides a detailed comparison of tuna RFMO transshipment measures, revealing alignment and gaps.
Building Toward a Shared Global Standard
Each tuna RFMO is at a different stage of development and modernization — and all can improve against the FAO global benchmark for transshipment.
Several common themes emerged in our analysis. The next phase of transshipment governance is not about creating entirely new systems: It’s about strengthening coordination, improving standardized data collection and interoperability, and making existing controls and monitoring tools more effective.
One top priority is improving coordination and data-sharing among RFMOs by establishing protocols for sharing transshipment information, alongside standardized data collection, accelerated reporting timelines, improved cross-referencing of data and enhanced monitoring through tools such as VMS, AIS, dedicated observer programs, and stronger Port state measures where fish is landed.
A second major priority is developing proactive, risk-based oversight mechanisms. No tuna RFMO fully implements systematic risk-based authorization processes for at-sea transshipment today. ISSF recommends establishing minimum standards and risk-based criteria for authorizing vessels to engage in transshipment activities — including consideration of compliance history, monitoring capacity, and vessel activity across multiple RFMO areas. This framework would focus monitoring resources while guiding consistent implementation across RFMO systems.
Our report contains an infographic that explains these needed improvements.
A Clear Path — and an Opportunity to Lead
Across all five tuna RFMOs, important monitoring, reporting, and compliance frameworks are already in place, and, in many cases, they continue to evolve and improve. The FAO Voluntary Guidelines provide a global benchmark that can align and strengthen these efforts.
Tuna fisheries and at-sea transshipment operations will continue to operate across oceans and jurisdictions — necessitating stronger coordination and monitoring, more consistent standards and better information-sharing — not only for effective fisheries management but also for improving transparency and accountability in global tuna fisheries.
