ISSF Technical Report 2025-08. June 2025, Version 12.0, 493 p.
The Marine Stewardship Council (MSC) has established a program whereby a fishery may be certified as being sustainable. The sustainability of a fishery is defined by MSC criteria which are embodied in three Principles: relating to the status of the stock, the ecosystem of which the stock is a member and the fishery management system. Since many of these MSC criteria are comparable for global tuna stocks, the MSC scoring system was used to evaluate twenty-three stocks of tropical and temperate tunas throughout the world and to evaluate the management systems of the Regional Fishery Management Organizations (RFMOs) associated with these stocks. No evaluation has been made here of the fishery specific ecosystem criteria in this report.
The principles that were assessed were:
- Principle 1 (P1): A fishery must be conducted in a manner that does not lead to over-fishing or depletion of the exploited populations and, for those populations that are depleted, the fishery must be conducted in a manner that demonstrably leads to their recovery, and
- Principle 3 (P3): The fishery is subject to an effective management system that respects local, national, and international laws and standards, and incorporates institutional and operational frameworks that require use of the resource to be responsible and sustainable.
Each of these Principles is evaluated in relation to Performance Indicators (PIs) within each Principle based on public information available by March 2025.
Of the 23 stocks of tropical and temperate tunas, 12 achieved a passing score for Principle 1. Failure was due to poor status of the stock, the lack of well-defined harvest control rules in place and the lack of effective tools to control harvest. Seven of the 23 stocks have fully implemented well-defined harvest control rules, and there has been progress towards this objective by all RFMOs. However, failure to implement controls before rebuilding is required has led to an increasing number of stocks failing to meet minimum requirements on harvest control rules.
Additionally, under Principle 3, RFMOs score well with a notable weakness in compliance.
While a future client tuna fishery will be evaluated on the merits related to all three MSC Principles, the scoring clearly outlines a template for actions to improve the management of the 23 tuna stocks.
