First Bigeye Management Workshop: Full Annotated Agenda

The SC Chair, Emily Crigler, will open the first BMW meeting and outline the purpose of the workshop.

The first session will begin with an overview of the WCPFC Harvest Strategy Workplan and the 2026 target for adopting a bigeye tuna Management Procedure (MP). The 2026 timeline includes  key decisions to be made, including the endorsement of the operating models (OMs) and the estimation method at SC22, and the spatial scope of the bigeye MP and the general shape of the Harvest Control Rule (HCR), which should be defined before the main analytical work gets underway, in preparation for the adoption of the bigeye MP at WCPFC23.

This session will summarise the mixed fishery framework under which the WCPFC Harvest Strategy Workplan is currently proceeding. It will highlight the current approach for bigeye MP development within this framework, describe the fishery interactions that need to be considered, and summarise the decisions that will need to be made to progress the analytical work, which will also be highlighted under the remaining agenda items.

Decision points

• Spatial range of the bigeye MP; and

• Fisheries managed through the bigeye MP

The BMW will focus on finalizing the target reference points (TRPs) for bigeye tuna by evaluating the three specific candidates identified at WCPFC21, which are based on the 2012–2015 average spawning biomass depletion level: 

1. A baseline TRP (estimated at 34% SBF=0 under the 2023 assessment); 

2. A lower depletion / higher biomass option representing a 1.06 multiplier of the baseline (36% SBF=0);and

3. A higher depletion option representing a 0.94 multiplier of the baseline (32% SBF=0). 

Central to this discussion will be the management clarification of whether these levels should function as "targets" to be achieved on average or as "thresholds" for the stock biomass depletion to be maintained above with a higher specified probability, ensuring the selected strategy aligns with the Commission’s long-term sustainability and stability objectives.

Decision points

• Whether the defined bigeye TRPs are actual targets or are to be considered as thresholds.

• If the bigeye TRPs are to be considered as thresholds, specify the probability that the spawning biomass depletion should be maintained above the thresholds.

The Harvest Strategy Workplan contained in CMM 2022-03 scheduled the refinement of candidate bigeye MPs to be done in 2025, with adoption targeted by the end of 2026. Work focuses on ensuring that fishery controls and HCR settings are designed to operate cohesively with other MP components, including data collection and the estimation method. 

Current technical discussions highlight key HCR design options, based on WCPFC22 guidance, including the PNA+ Bigeye MP guidance, and approaches to capture the balance between longline and purse seine fisheries. The analytical approach developed in response to this guidance will be presented. An update will also be provided on the development of the estimation method, taking into account guidance provided by the Commission at WCPFC21 and by SC21.  

An overview of the necessary assumptions that underpin the Management Strategy Evaluation (MSE) will be provided, including the levels of fishing of bigeye that occur outside the proposed spatial range of the MP. Additionally, the Commission has requested sensitivity analyses to address uncertainties in the archipelagic fisheries of Indonesia & Philippines, and coastal fisheries of Vietnam. It will be necessary to confirm the spatial range of the MP and candidate catch levels for areas outside the MP’s control.

Candidate performance indicators will be presented, including the probability of the stock remaining above Maximum Sustainable Yield (MSY), as requested by the Commission at WCPFC22.

It will be necessary to confirm whether the MP should generate catch controls or effort controls, and the frequency of MP implementation (e.g., a three-year management cycle). In addition, the spatial scope and fleet coverage of the bigeye MP within the mixed-fishery framework must be finalized, ensuring consistency with existing MPs for skipjack and south Pacific albacore. As with the adopted MP for south Pacific albacore, the output of a catch or effort control for a fishery component by the MP does not prevent or preclude practical implementation through the alternative management measure, such as through effort or catch limits, respectively.

BMW01 should provide guidance on the implementation of meta-rules, such as a ±10% constraint on changes in management levels, to ensure sectoral stability and prevent disruptive fluctuations in catch or effort between management periods.

Decision points

• Spatial range of the bigeye MP (if not defined under Agenda Item 3);

• Fisheries managed through the bigeye MP (if not defined under Agenda Item 3);

• General shape and operation of the HCR;

• Duration of management period (WCPFC22 guidance was a 3 year period);

• Assumed future catch levels of bigeye in areas outside of the spatial range of the bigeye MP (for ‘reference set’ evaluations and additional ‘robustness set’ tests);

• Candidate performance indicators, noting that a smaller set of indicators is preferred to facilitate stakeholder decision-making;

• Output controls of the bigeye MP, e.g., longline catch or effort; purse seine FAD closure period. Desired increment of change, for example, in FAD closure period (e.g., +/- month, week(s)); and

• Meta rule(s) for evaluation, e.g., constraints on the maximum change in fishing pressure between management periods.

This agenda item addresses the administrative and technical frameworks required to transition the bigeye MP from a theoretical model to an operational reality. Based on the progress and decision points outlined in the Commission’s recent guidance, the current status identifies a support for a three-year management cycle utilizing a two-year data lag. To support this, the Commission has requested the development of candidate Management Procedures that include controls for both tropical longline and tropical purse seine fisheries to ensure a comprehensive management approach.

To ensure seamless implementation, these arrangements could be operationalized through existing conservation and management measures, such as CMM 2025-02. These technical and administrative refinements are essential to provide the Commission with a high level of confidence in the Management Procedure's ability to maintain the stock at or above the agreed target levels without requiring entirely new or costly implementation systems.

Decision points

• Duration of management period (also considered in earlier agenda item).

• Implementing measure of the bigeye MP outputs.