The International Seafood Sustainability Foundation (ISSF) has published the latest edition of An Evaluation of the Sustainability of Global Tuna Stocks Relative to Marine Stewardship Council Criteria. Co-authored by Matthew Cieri and Paul A. H. Medley, the assessment finds that 16 of the world’s 23 tropical and temperate tuna stocks now achieve a passing score for Marine Stewardship Council (MSC) Principle 1, compared with 12 in the previous edition, reflecting continued improvements in stock status and fisheries management. The 2026 update does not include updates to MSC Principle 3 (Effective Management), which was comprehensively reassessed in the previous edition.
Several stocks achieved higher Principle 1 scores following updated stock assessments and fisheries management improvements, including adoption and implementation of harvest control rules. A passing score requires an overall score of at least 80, with no individual performance indicator scoring below 60.
“The updated assessment reflects encouraging progress across tuna fisheries while also identifying where additional work remains,” said Susan Jackson, ISSF President. “Using a consistent framework to evaluate global tuna stocks helps fisheries managers, market partners, and other stakeholders better understand both the advances being made and the management priorities that will support continued improvement.”
Since 2013, ISSF’s annual Evaluation report has provided a consistent, science-based framework for assessing global tuna fisheries against MSC sustainability criteria. Using the MSC Fisheries Standard as a common benchmark, the report offers an objective comparison of how the world’s major tuna stocks perform against internationally recognized sustainability standards, while highlighting areas where further management improvements are needed.
Key Findings
The 16 tuna stocks receiving passing MSC Principle 1 scores are:
- Atlantic Ocean: Bigeye, Western skipjack, Northern albacore, Southern albacore, Eastern bluefin
- Pacific Ocean: Western yellowfin, Western bigeye, Western skipjack, Eastern yellowfin, Eastern skipjack, Southern albacore
- Indian Ocean: Yellowfin, bigeye, skipjack, albacore
- Southern Hemisphere: Southern bluefin
Several of these stocks received higher MSC Principle 1 scores following updated stock assessments and/or fisheries management actions, including:
- Atlantic Ocean: Bigeye, Western skipjack
- Pacific Ocean: Eastern yellowfin, Southern albacore
- Indian Ocean: Bigeye, yellowfin, albacore
While not all of these stocks moved from failing to passing, each showed improvement in one or more underlying MSC Principle 1 performance indicators.
The report also finds that nine of the 23 assessed tuna stocks now have fully implemented well-defined harvest control rules, an increase from seven in the previous edition. Progress toward harvest control rule implementation has been made across all five tuna Regional Fisheries Management Organizations (RFMOs) in recent years.
“The increase from 12 to 16 tuna stocks meeting MSC Principle 1 reflects meaningful progress in both stock status and science-based fisheries management,” said Dr. Victor Restrepo, ISSF Vice President of Science and Chair of the ISSF Scientific Advisory Committee. “Continued implementation of well-defined harvest control rules will be essential to sustaining that momentum and advancing additional stocks.”
