ISSF has expanded its Vessels in Other Sustainability Initiatives (VOSI) tool with four new indicators covering biodegradable FAD use and seabird bycatch mitigation. The update also revises criteria for recognizing vessels using electronic monitoring. VOSI now tracks 15 individual best practices, providing independently verified information on steps vessels are taking to reduce their environmental impacts.
What do seabird protection measures look like on board a fishing vessel? ISSF’s Skippers’ Guidebook to Sustainable Longline Fishing Practices explains techniques to reduce seabird bycatch, including the practices recognized by VOSI’s new indicators. The guidebook is available online in English and as downloadable PDFs in several languages.
VOSI recognition goes beyond a vessel’s stated commitment. Independent auditor MRAG Americas verifies each listed vessel’s recognized best practices, helping turn commitments into information that stakeholders can review and use.
ISSF has suspended PT Aneka Tuna Indonesia (ATI) from participation following a major non-conformance with an ISSF conservation measure in two consecutive annual independent audit cycles. The ISSF Board voted to suspend ATI on September 23, 2026, effective immediately. ATI is no longer an ISSF participating company.
Harvest strategies set out management rules in advance, helping tuna fisheries managers respond more predictably as stock conditions change. In a Q&A, leaders from WCPFC and ISSF discuss what it takes to move these approaches from agreement to implementation—and what other tuna RFMOs can learn from that experience.
About 52% of the global tuna catch comes from stocks with adopted harvest strategies, also called management procedures. ISSF’s Status of the Stocks report tracks where these approaches are in place and where further work is needed.
Recent ISSF research provides new insights into the vessels behind three-quarters of the world’s tuna catch.
ISSF’s first global analysis of tuna longline fleets identified 7,288 unique vessels registered across five tuna RFMOs. The updated purse-seine fleet snapshot estimates 693 large-scale purse-seine vessels target tropical tuna worldwide, with a combined fish hold volume (FHV) of approximately 895,000 m³.Together, the analyses offer insights into fleet composition, distribution, and fishing capacity — highlighting the importance of complete, consistent, and transparent vessel data.
Among large-scale purse-seine vessels targeting tropical tuna, 73% — representing 83% of FHV — are listed on the ProActive Vessel Register (PVR), while 58% — representing 69% of FHV — are listed on Vessels in Other Sustainability Initiatives (VOSI).
The PVR provides independently audited information on compliance with applicable ISSF conservation measures; VOSI shows vessel participation in other tuna sustainability initiatives.
ISSF Participating Companies must ensure that 100% of the large-scale purse-seine vessels they purchase tropical tuna from are listed on the ProActive Vessel Register (PVR).
New Snapshot Tracks Global Purse-Seine Fleet Capacity
ISSF’s latest annual snapshot estimates 693 large-scale purse-seine vessels are fishing for tropical tuna, with a combined fish hold volume (FHV) of approximately 895,000 m³. Both vessel numbers and FHV increased about 3% over the past year.
The report also expands its analysis of vessel participation in ISSF transparency tools: 73% of vessels, representing 83% of FHV, are listed on the ProActive Vessel Register (PVR), while 58% of vessels, representing 69% of FHV, are listed on Vessels in Other Sustainability Initiatives (VOSI).
Susan Jackson: Facing Tuna’s Challenges with Confidence
In a guest editorial for TUNA 2026, ISSF President and conference chair Susan Jackson reflects on progress in tuna fisheries — and opportunities to continue advancing science-based management, monitoring, and transparency.
IMO number adoption among large-scale purse-seine vessels targeting tropical tunas has increased from 12% in 2011 to 99% today. Expanding IMO number use across more vessel types and sizes can further strengthen vessel identification and transparency.
Fish Focus reports on ISSF’s assessment of the 2026 IATTC annual meeting, including progress on Pacific bluefin tuna, South Pacific albacore, electronic monitoring, and ecosystem management — and key decisions deferred to 2027.
IATTC Makes Progress, But Key Tuna Decisions Move to 2027
The IATTC made progress on Pacific bluefin tuna, South Pacific albacore, electronic monitoring, and ecosystem management at its annual meeting. But several major ISSF priorities, including a management procedure for tropical tunas and stronger shark conservation measures, were deferred. Read the new ISSF meeting recap for the outcomes and priorities heading into 2027.
Assessing the Environmental Impacts of Tuna Fisheries
An updated ISSF analysis examines the impacts of major tuna fishing methods on non-tuna species, habitats, and the broader marine environment. The report also reviews measures adopted by tuna RFMOs and ISSF to mitigate those impacts.
All four tuna RFMOs are already working with ecosystem indicators — but most are not yet routinely used to inform management decisions. A new ISSF technical report examines how ecosystem indicators can better inform fisheries management decisions.
How do international fisheries policy and governance translate into progress for tuna fisheries? On the How to Protect the Ocean podcast, ISSF Vice President of Policy and Outreach Holly Koehler discusses RFMO decision-making, the evolution of tuna management, and how ISSF works across the tuna supply chain to advance conservation, transparency, and accountability.
A Clearer Picture of the Global Tuna Longline Fleet
ISSF’s first global analysis of tuna longline fleets brings together vessel registry data from all five tuna RFMOs, providing a clearer picture of fleet composition, characteristics, and fishing capacity. The analysis of 7,288 unique longline vessels also identifies opportunities to improve the completeness, consistency, traceability, and transparency of vessel information that supports fisheries science and management.
All tropical tuna RFMOs now prohibit netting material in drifting FADs. ISSF’s latest environmental impacts report reviews RFMO measures and other mitigation efforts addressing the impacts of tuna fisheries on non-tuna species and marine ecosystems.
ISSF President Susan Jackson will serve as Chairperson of the 19th INFOFISH World Tuna Trade Conference & Exhibition, taking place September 14–16 in Bangkok. The global gathering will bring together tuna industry leaders, policymakers, RFMOs, researchers, and other stakeholders to discuss sustainability, trade, technology, traceability, and other issues shaping the future of the tuna industry.
Q&A: Verifying Sustainability Commitments in the Global Seafood Supply Chain
What makes a sustainability commitment credible — and how can stakeholders know whether companies are following through?
ISSF President Susan Jackson and MRAG Americas Vice President Dr. Graeme Parkes discuss more than a decade of independent auditing of ISSF participating companies, including how audits work, why transparency matters, and what the results show about progress over time.
Q&A: Moving Harvest Strategies from Concept to Implementation
Harvest strategies are changing how tuna fisheries are managed — replacing year-to-year negotiations with pre-agreed rules that help managers respond more predictably as stock status changes.
In a new joint Q&A, ISSF President Susan Jackson and WCPFC Executive Director Rhea Moss-Christian discuss the progress tuna RFMOs have made in putting harvest strategies into practice, including WCPFC’s work on skipjack and North and South Pacific albacore. They also explore what this experience can teach the broader ocean governance community and how greater knowledge-sharing among RFMOs can accelerate progress globally.
Updated Evaluation Tracks Progress Against MSC Stock Requirements
How do the world’s major commercial tuna stocks measure up against Marine Stewardship Council Principle 1 requirements?
ISSF’s latest evaluation applies the MSC Fisheries Standard criteria for sustainable fish stocks to 23 major commercial tuna stocks. The analysis highlights continued improvements in stock status while also identifying where stronger harvest strategies and management procedures are still needed.
Explore the results, including a summary of key findings and the full technical report.
ISSF helps move fisheries science into practice. Our scientists work directly with tuna RFMOs and their scientific bodies, contributing research, technical expertise, and practical tools that support stronger fisheries management — from harvest strategies and bycatch mitigation to FAD management and electronic monitoring.
That sustained scientific engagement helps ensure that solutions are not only grounded in research but designed for real-world implementation.
When the Inter-American Tropical Tuna Commission (IATTC) meets in late August, delegates will have an opportunity to turn recent advances in fisheries science and management into stronger conservation and management measures for Eastern Pacific tuna fisheries.
Over the past several years, IATTC has advanced management strategy evaluation (MSE) work for tropical tunas, adopted interim electronic monitoring (EM) standards, begun transitioning to fully biodegradable fish aggregating devices (FADs), and strengthened its compliance assessment process. The Commission’s latest scientific advice also indicates that bigeye, yellowfin, and skipjack tuna stocks in the eastern Pacific Ocean remain in healthy condition.
These advances provide a strong foundation, but additional action is needed to effectively manage tuna fisheries and their ecosystem. ISSF’s 2026 position statement highlights three priorities that can help IATTC continue making progress.
Updated ISSF Assessment Shows Continued Progress in Global Tuna Stock Management
ISSF has published the 2026 edition of An Evaluation of the Sustainability of Global Tuna Stocks Relative to Marine Stewardship Council (MSC) Criteria, an annual assessment that uses the MSC Fisheries Standard as a consistent benchmark to evaluate the world’s major tuna stocks. The latest report finds that 16 of 23 assessed tuna stocks now achieve a passing score for MSC Principle 1 (Sustainable Fish Stocks), up from 12 in the previous edition, reflecting improvements in stock status and fisheries management.
The report also shows continued progress in the adoption and implementation of harvest control rules, with nine of the 23 assessed stocks now managed under fully implemented, well-defined harvest control rules, compared with seven in the previous edition. While additional management improvements remain necessary for some stocks, the assessment provides a consistent framework for tracking progress over time and identifying priorities for continued improvement.
ISSF participating companies demonstrate their commitment through independent audits and public reporting against ISSF conservation measures. Buyer and retailer sustainability policies increasingly reference ISSF participation and ISSF’s ProActive Vessel Register (PVR) and Vessels in Other Sustainability Initiatives (VOSI), helping companies transparently demonstrate progress toward procurement criteria and customer expectations.
Updated ISSF Assessment Shows Continued Progress in Global Tuna Stock Management
ISSF has published the 2026 edition of An Evaluation of the Sustainability of Global Tuna Stocks Relative to Marine Stewardship Council (MSC) Criteria, an annual assessment that uses the MSC Fisheries Standard as a consistent benchmark to evaluate the world’s major tuna stocks. The latest report finds that 16 of 23 assessed tuna stocks now achieve a passing score for MSC Principle 1 (Sustainable Fish Stocks), up from 12 in the previous edition, reflecting improvements in stock status and fisheries management.
The report also shows continued progress in the adoption and implementation of harvest control rules, with nine of the 23 assessed stocks now managed under fully implemented, well-defined harvest control rules, compared with seven in the previous edition. While additional management improvements remain necessary for some stocks, the assessment provides a consistent framework for tracking progress over time and identifying priorities for continued improvement.
A new ISSF report identifies 7,288 unique tuna longline vessels registered across the world’s five tuna RFMOs — the first time these registries have been harmonized into a single global analysis.
