Multi-stock Tropical Tunas MSE

(Bigeye/Yellowfin/Eastern Skipjack)

Generated by ChatGPT on 15 Feb 2026

 


Overview

ICCAT has formally initiated the development of a multi-stock MSE for tropical tunas: Atlantic bigeye tuna, Atlantic yellowfin tuna, and eastern Atlantic skipjack (Anon., 2021). The objective is to design and evaluate robust Management Procedures (MPs) that support the sustainable harvest of all three species within a mixed-fishery context. The components of the MSE simulations are refined, and Candidate Management Procedures (CMPs) are being evaluated. The SCRS plans to provide the final CMPs results to the Commission in 2026. Res. 24-02 considers the interim operational management objectives for the purpose of developing, testing, and refining CMPs.

OMs development in 2021-2026 MP adoption plan in 2026 ECP adoption plan in 2027
Recondition not planned MP not defined ECs evaluation not started

History

The MSE for the Atlantic tropical tuna stocks started gradually in 2018 with the development of a workplan for the MSE by the SCRS (Anon., 2018). The SCRS formally initiated the development of a multi-species MSE framework in 2021 (Anon., 2021) because the Commission decided to slow down the MSE process for tropical tunas, noting the potential complexities surrounding a multi-stock MSE process for tropical tunas (Anon., 2020).

Rec. 21-01 established the foundation for the development of harvest strategies for tropical tunas. This was further reinforced by Rec. 24-01, which reaffirms the Commission’s commitment to adopt harvest control rules (HCRs) informed by Management Strategy Evaluation (MSE) outcomes for bigeye, yellowfin, and skipjack tunas in 2026 or as soon as possible thereafter. In 2024, ICCAT adopted Res. 24-02 on interim operational management objectives for tropical tunas (bigeye, yellowfin, and eastern skipjack).

Operating Models (OMs)

The OMs for individual species: Atlantic Bigeye tuna (BET), Yellowfin tuna (YFT), and eastern Atlantic Skipjack (SKJ-E), have been developed based on their stock assessments in 2021 (Anon., 2021), 2024 (Anon., 2024), and 2022 (Anon., 2022), respectively. The Operating Models (OMs) represent a range of plausible dynamics for the three stocks. The reference set of 4374 OMs was considered to represent a range of plausible dynamics of the three stocks, including uncertainty in biology (steepness, natural mortality) and data weighting (CPUEs). The Reference OMs were conditioned in FLBEIA.

Materials
More materials can be found in References
Summary MSE Codes
 Shiny App
  Under development Under development





Interim Operational Management Objectives

Rec. 24-02

 

Stock Status Safety Yield Stability
Prob. >= 50% in green quadrant for all three stocks Prob. <= 15% of stock falling below BLIM for all three stocks Maximize overall catch for all three stocks TAC changes between periods +25%/-25% for all three stocks





Candidate Management Procedures (CMPs)

Currently, only model-based Harvest Control Rules (HCRs) have been considered with several combinations of Ftarget and Btrigger. Advice for multi-stock fisheries would be generated through three species-specific HCRs evaluated against species-specific Operating Models (OMs), with each individual species’ Total Allowable Catch (TAC) adjusted based on the fishing efforts corresponding to the stock in the poorest condition among the three.

 

Management Procedure (MP)

The Commission plans to adopt an MP in 2026 (or as soon as possible thereafter).


Exceptional Circumstances (EC)

The Commission plans to adopt the Exceptional Circumstances Protocol (ECP) in 2027 (or as soon as possible thereafter).

References of Multi-stock tropical tunas

Meeting Reports
Year Ref Document
2025 SCRS REPORT OF THE STANDING COMMITTEE ON RESEARCH AND STATISTICS (SCRS)
2024 Commission 24th Special Meeting of the Commission
2024 SCRS REPORT OF THE STANDING COMMITTEE ON RESEARCH AND STATISTICS (SCRS)
2024 WGSAM Meeting Meeting of the Working Group on Stock Assessment Methods (WGSAM)
2024 YFT DP Meeting Yellowfin Data Preparatory Meeting
2024 YFT SA Meeting Yellowfin Tuna Stock Assessment Meeting
2023 Commission 28th Regular Meeting of the Commission
2023 SCRS REPORT OF THE STANDING COMMITTEE ON RESEARCH AND STATISTICS (SCRS)
2023 WGSAM Meeting Meeting of the Working Group on Stock Assessment Methods (WGSAM)
2022 Commission 23rd Special Meeting of the Commission
2022 SCRS REPORT OF THE STANDING COMMITTEE ON RESEARCH AND STATISTICS (SCRS)
2022 SKJ DP Meeting Report of the skipjack stock assessment meeting (online, 23-27 May 2022)
2022 SKJ SA Meeting Report of the skipjack data preparatory meeting (online, 21-25 February 2022)
2022 WGSAM Meeting Meeting of the Working Group on Stock Assessment Methods (WGSAM)
2021 BET DP Meeting REPORT OF THE 2021 BIGEYE TUNA DATA PREPARATORY MEETING (Online, 22 - 30 April 2021)
2021 BET SA Meeting REPORT OF THE 2021 BIGEYE STOCK ASSESSMENT MEETING (Online, 19- 29 July 2021)
2021 Commission 27th Regular meeting of the Commission
2021 SCRS REPORT OF THE STANDING COMMITTEE ON RESEARCH AND STATISTICS (SCRS)
2021 TTMSE Meeting REPORT OF THE TROPICAL TUNAS MSE TECHNICAL GROUP MEETING (Online 29-31 March 2021)
2021 WGSAM Meeting Meeting of the Working Group on Stock Assessment Methods
2020 Commission 22nd Special Meeting of the Commission
2020 SCRS 2020 SCRS Advice to the Commission
2020 WGSAM Meeting Intersessional meeting of the Working Group on Stock Assessment Methods
2019 Commission 26th Regular Meeting of the Commission
2019 SCRS REPORT OF THE STANDING COMMITTEE ON RESEARCH AND STATISTICS (SCRS)
2019 WGSAM Meeting 2019 REPORT OF THE 2019 ICCAT WORKING GROUP ON STOCK ASSESSMENT METHODS MEETING (WGSAM)
2018 Commission 21st Special Meeting of the Commission
2018 SCRS REPORT OF THE STANDING COMMITTEE ON RESEARCH AND STATISTICS (SCRS)
2018 WGSAM Meeting Meeting of the ICCAT Working Group on stock assessment methods
2017 Commission 25th Regular Meeting of the Commission
2017 SCRS REPORT OF THE STANDING COMMITTEE ON RESEARCH AND STATISTICS (SCRS)
2017 WGSAM Meeting Meeting of the ICCAT Working Group on Stock Assessment Methods
2016 Commission 20th Special Meeting of the Commission
2016 SCRS Meeting of the Standing Committee on Research and statistics
2015 Commission 24th Regular Meeting of the Commission
2015 SCRS Meeting of the Standing Committee on Research and statistics
2014 SCRS Meeting of the Standing Committee on Research and statistics 
2014 SWGSM Meeting FIRST MEETING OF THE STANDING WORKING GROUP TO ENHANCE DIALOGUE BETWEEN FISHERIES SCIENTISTS AND MANAGERS (SWGSM) (Barcelona, Spain, 26-28 May 2014)
2013 SCRS Meeting of the Standing Committee on Research and statistics 
COMMISSION Documents
COMMISSION/SCRS Documents
SCRS Documents
Year Ref Document
2025 SCRS/2025/019 REPORT OF THE PROJECT “EXTERNAL" REVIEW OF THE OVERALL ICCAT MSE PROCESS
2025 SCRS/2025/068 Modelling approaches: support to ICCAT tropical tunas multi-stock MSE process in 2024
2025 SCRS/2025/118 Management Procedures and Climate Change - A Review of the Literature
2025 SCRS/2025/151 Preliminary 2025 stock synthesis assessment model for bigeye tuna in the Atlantic Ocean.
2024 SCRS/2024/017 Report of ICCAT capacity building workshops for management strategy evaluation in tropical tuna fisheries
2024 SCRS/2024/028 A REVIEW OF OBJECTIVES, REFERENCE POINTS, AND PERFORMANCE INDICATORS FOR MANAGEMENT STRATEGY EVALUATION AT TRFMOS
2024 SCRS/2024/081 Incorporating climate considerations into fisheries assessments and management advice at ICCAT
2024 SCRS/2024/110 Atlantic yellowfin tuna stock synthesis population analyses.
2024 SCRS/2024/111 Atlantic yellowfin tuna stock synthesis population analyses: sensitivity exploration and proposal for a reference grid with diagnostics
2024 SCRS/2024/118 Incorporating Climate Change effects in the management strategy evaluation for Atlantic Tropical tunas.
2024 SCRS/2024/148 DEVELOPING THE CLIMATE TEST: PERFORMANCE METRICS OF CLIMATE ROBUSTNESS
2024 SCRS/2024/149 An Updated Roadmap for MSE development 
2024 SCRS/2024/157 Is PGK an appropriate performance statistic for MP performance and selection?
2023 SCRS/2023/020 OPTIONS FOR MULTISPECIES MANAGEMENT OBJECTIVES FOR TROPICAL TUNAS
2023 SCRS/2023/070 A Review of Reference Points, Objectives, and Performance Standards at tRMFOs
2023 SCRS/2023/141 DEVELOPMENT OF OPERATING MODELS FOR TROPICAL TUNAS' MANAGEMENT STRATEGY EVALUATION (MSE)
2022 SCRS/2022/095 East Atlantic skipjack tuna Stock Synthesis analyses
2022 SCRS/2022/135 Intersessional work on the Eastern Atlantic skipjack stock synthesis assessment model
2021 SCRS/2021/016 CHARACTERIZATION OF STRUCTURAL UNCERTAINTY IN TROPICAL TUNA STOCKS’ DYNAMICS
2021 SCRS/2021/055 PROGRESS ON CHARACTERIZATION OF STRUCTURAL UNCERTAINTY IN TROPICAL TUNA STOCKS’ DYNAMICS WITH SUMMARY OF DISCUSSIONS HELD DURING THE TROPICAL TUNA MSE MEETING (29-31 MARCH 2021)
2021 SCRS/2021/134 Atlantic Bigeye Tuna Stock Synthesis Analyses
2019 SCRS/2019/015 Observation Error Model for Tropical Tuna Fisheries in a Management Strategy Evaluation Framework
2019 SCRS/2019/033 Final report of the ICCAT short-term contract: Modelling approaches - Support to ICCAT tropical tunas MSE process
2019 SCRS/2019/033 FINAL REPORT OF THE ICCAT SHORT-TERM CONTRACT: MODELLING APPROACHES - SUPPORT TO ICCAT TROPICAL TUNAS MSE PROCESS
2019 SCRS/2019/056 AN ANALYTICAL APPROACH FOR DIAGNOSTICS OF PARAMETERS ESTIMATION IN MANAGEMENT STRATEGY EVALUATION
2019 SCRS/2019/121 Stock synthesis model for Atlantic yellowfin tuna
2018 SCRS/2018/111 Atlantic bigeye tuna stock assessment in Stock Synthesis
2018 SCRS/2018/112 A simple operating model for a basis of a discussion about the development of a management strategy evaluation for tropical tuna fisheries
2018 SCRS/2018/146 The steps to consider during the conditioning of the oms of a multi-specific model of tropical tuna fisheries in a management strategy evaluation framework
2017 SCRS/2016/014 Conditioning operating models on data and knowledge and rejecting and weighting of hypotheses
2012 SCRS/2011/146 An evaluation of a Harvest Control Rule using limits and target reference points: An Atlantic yellowfin example.
2004 SCRS/2004/063 The development of an operational model and simulation procedure for testing uncertainties in the Atlantic bigeye (Thunnus obesus) stock assessment.
Others
Year Ref Document
2025 Capacity building How to efficiently craft a management procedure
2025 Capacity building Management Procedures and Management Strategy Evaluation: A Brief Guide for Managers
2025 Capacity building Management procedures versus traditional fisheries management
2025 Codes FLBEIA Code
2025 Harvest Strategies Glossary Harvest Strategies Glossary
2025 IATTC WSMSE-05-01 OVERVIEW OF THE MANAGENEMENT STRATEGY EVALUATION (MSE) PROCESS FOR TROPICAL TUNAS AT IATTC
2025 IOTC IOTC MSE capacity building tools
2025 SCRS/P/2025/001 Climate change or something else, the need to update management benchmarks
2025 SCRS/P/2025/004 Harvest Control Rules for multi-stock tropical tuna fisheries.
2025 SCRS/P/2025/009 Proposal on the ICCAT MSE website by Ad-hoc Sub-group on MSE Communication
2025 SCRS/P/2025/026 MSE simulations for multi-stock Atlantic tropical tuna fisheries using hybrid HCRs
2025 SCRS/P/2025/062 Management Procedure for Multistock MSE: How will it work when adopted.
2025 SCRS/P/2025/094 Current state of the multi-stock MSE for tropical tunas and workplan.
2025 SCRS/P/2025/095 Preliminary evaluations of multi-stock MPs for tropical tunas.
2024 Capacity building Assessment of Candidate Management Procedures and Harvest Control Rules for the Western Atlantic Skipjack Tuna
2024 Capacity building How is MSE based MPs different from current stock assessment practice?
2024 Capacity building HOW TO PUT A MANAGEMENT PROCEDURE TOGETHER
2024 Capacity building Management Procedure Elements
2024 Capacity building Objective of MSE simulations
2024 Capacity building Reference Points & Rules: Managing fisheries for the future
2024 Capacity building Restoring Pacific saury to a predictable and productive fishery
2024 Capacity building What is an MSE based MP?
2024 SCRS/P/2024/074 FLBEIA: A simulation model to conduct Bio-Economic evaluation of fisheries management strategies
2024 SCRS/P/2024/076 State of development of tropical tuna Management Strategy Evaluation
2024 SCRS/P/2024/078 MSE Process Scorecard for ICCAT Stocks
2024 SCRS/P/2024/081 Harvest control rule options for multi-stock tropical tuna MSE: Demersal fisheries Bay of Biscay case study
2024 SCRS/P/2024/103 Workplan for tropical tunas MSE in 2024
2024 SCRS/P/2024/108 Development of operational management objectives for tropical tunas
2023 Capacity building Two Tools Can Help Make Ecosystem-Based Fisheries Management a Global Reality
2023 openMSE Open Source Software for Management Strategy Evaluation
2023 SCRS/P/2023/051 A Review of Reference Points, Objectives, and Performance Standards at tRMFOs
2023 SCRS/P/2023/093 Observation Error Model (OEM) for the tropical tuna multispecies MSE.
2022 Capacity building To Strengthen Fishery Management, RFMOs Should Use Science-Management Dialogue Groups
2022 SCRS/P/2022/020 Atlantic Tropical Tuna Management Strategy Evaluation (MSE)
2021 Capacity building Harvest strategies: Fisheries Management for the 21st Century
2021 Codes openMSE Code
2021 SCRS/P/2021/025 Atlantic tropical tuna MSE
2020 SCRS/P/2020/021 Summary of tropical tuna MSE
2019 Capacity building Harvest Strategies: 21st Century Fisheries Management
2019 ICCAT WS ICCAT MSE Introductory Workshop in 2019
2018 SCRS/2018/147 Management procedure options for a Management Strategy Evaluation in tropical tuna fisheries
2018 SCRS/P/2018/019 Current state of MSE/HCR Process in ICCAT
2018 SCRS/P/2018/020 What makes an MP an MP and an MSE an MSE?
2018 SCRS/P/2018/021 Operating model for North Atlantic swordfish (Xiphias gladius)
2018 SCRS/P/2018/052 Initial development of a stock synthesis model for Eastern skipjack tuna to support tropical tuna management strategy evaluation
2018 SCRS/P/2018/053 The initial steps of a shiny web application developed to facilitate communication and share the results of the management strategy evaluation model for tropical tuna fisheries
2018 tRFMO MSE Glossary Glossary of terms for harvest strategies, management procedures and management strategy evaluation
2018 tRFMO MSE meeting REPORT OF THE 2018 JOINT TUNA RFMO MANAGEMENT STRATEGY EVALUATION WORKING GROUP MEETING (Seattle, USA – 13-15 June 2018)
2018 tRFMO MSE Working Group Joint Tuna RFMO Management Strategy Evaluation Working Group
2016 Capacity building Harvest Control Rules
2016 Capacity building Management Objectives
2016 Capacity building Management Strategy Evaluation for Fisheries
2016 Capacity building Reference Points
2015 Capacity building Harvest strategies
2014 IATTC SAC-05-10b MANAGEMENT STRATEGY EVALUATION (MSE) IMPLEMENTATION IN STOCK SYNTHESIS: APPLICATION TO PACIFIC BLUEFIN TUNA
2014 ICES Journal of Marine Science, 71(2): 195–203 Implementing harvest strategies in Australia: 5 years on
2003 North American Journal of Fisheries Management, 23: 349–361 Targets and Limits for Management of Fisheries: A Simple Probability-Based Approach
1998 Canadian Journal of Fisheries and Aquatic Sciences, 55(6): 1545–1552 Recent international agreements and the precautionary approach: new directions for fisheries management science
1996 FAO FAO precautionary approach to capture fisheries and species introduction