WCPFC Harvest Strategy
Harvest Strategy CMM 2014-06
WCPFC11 agreed to Conservation and Management Measures to develop and implement a harvest strategy approach for key fisheries and stocks in the WCPO (326.23 KB) The objective of the CMM 2014-06 is "To agree that the Commission shall develop and implement a harvest strategy approach for each of the key fisheries or stocks under the purview of the Commission according to the process set out in CMM 2014-06."
Pursuant to paragraph 13 of CMM 2014-06, WCPFC12 agreed a workplan for adoption of Harvest Strategies under CMM 2014-06 Workplan for the adoption of Harvest Strategies under CMM 2014-06 (506.05 KB) An updated workplan has been agreed annually by the Commission and this records the Harvest Strategy Outcomes. The latest version of the Workplan can be accessed here, and copies of the past Workplans are provided in the Key Documents table below.
I. Harvest Control Rules (HCRs) and Management Strategy Evaluation (MSE)
1. SC16 provided updated information since SC15, which is embedded under this section together with meeting documents for SC16. All cited papers below are attached in the Key Documents table below.
2. A workshop paper on the external review of the MSE development, SC15-MI-IP-03 (Report of the Second Expert Consultation Workshop on Management Strategy Evaluation), was noted.
3. At SC16, because of the characteristics of the virtual meeting, SC16 simply noted a Report of the second external MSE technical review: Developments in the SP-ALB MSE framework (SC16-MI-IP-11), which addressed many of the technical elements of the work regarding OM conditioning, simulating CPUE indices, the design of HCRs, etc.
1.1 Review of harvest control rules for skipjack tuna
Evaluations of management procedures
4. Information on the MSE framework for skipjack (SC15-MI-WP-05, Results of Initial Evaluations of Management Procedures for Skipjack) was presented at the SC15, which summarizes the results of recent evaluations and consideration on next steps to meet the harvest strategy work-plan. This paper should be considered along with SC15-MI-IP-02 (The WCPO Skipjack MSE Modeling Framework), SC15-MI-WP-06 (Considering Uncertainty When Testing and Monitoring WCPFC Harvest Strategies), and SC15-MI-WP-09 (Harvest strategy engagement tools). This paper provides a brief summary of the results of the evaluations and encourages members to use the web-based tool PIMPLE (Performance Indicators and Management Procedures Explorer) to interrogate the results in more detail. PIMPLE can be accessed at https://ofp-sam.shinyapps.io/pimple/.
5. SC16 reviewed an Overview of recent developments and key decisions for harvest strategies for WCPFC stocks and fisheries (SC16-MI-WP-03), which briefly summarizes the contents of ten information papers (SC16-MI-IP-02 ~ SC16-MI-IP-11). Among the ten papers, two papers (SC16-MI-IP-03 and SC16-MI-IP-09) covered management procedure issues for skipjack tuna.
Uncertainty in testing and monitoring harvest strategies
6. The paper SC15-MI-WP-06 (Considering Uncertainty When Testing and Monitoring WCPFC Harvest Strategies) describes the initial developments in the harvest strategies for WCPO skipjack and South Pacific albacore focusing on the inclusion of uncertainty in the evaluations to test candidate management procedures through the use of a reference set of plausible uncertainty scenarios. SC15-MI-IP-02 (The WCPO Skipjack MSE Modelling Framework) and SC15-MI-WP-03 (Performance indicators for comparing management procedures for South Paciﬁc albacore using the MSE modelling framework) provide additional information in this respect for skipjack and albacore respectively.
7. At SC16, three information papers were provided related to testing and monitoring harvest strategies: Developing the monitoring strategy for the WCPFC harvest strategy for WCPO skipjack (SC16-MI-IP-02), Updating the WCPO skipjack operating models for the 2019 stock assessment (SC16-MI-IP-08) and Simulating future data for WCPO skipjack harvest strategy evaluations (SC16-MI-IP-10). Noting that the virtual SC16 meeting had not provided enough time to consider the ten information papers including these two, SC16 agreed to continue discussions on these ten papers through the WCPFC Online Discussion Forum (https://forum.wcpfc.int/c/HS-Framework/12).
Harvest strategy engagement tools
8. To assist with capacity building on harvest strategy process, three interactive software tools have been developed, and will be updated, which demonstrate how HCRs and MPs work (SC15-MI-WP-09 Harvest strategy engagement tools). These software tools explore the basic operation of HCRs, how different HCRs can give different performance, the impact and importance of uncertainty, measuring the performance of HCRs and how to compare and choose between a suite of candidate MPs. The tools and tutorials can be seen at
- https://ofp-sam.shinyapps.io/amped-intro-hcr/ (introduction to HCRs),
- https://ofp-sam.shinyapps.io/amped-intro-indicators/ (introduction to uncertainty and performance indicators) and
- https://ofp-sam.shinyapps.io/amped-comparing-performance/ (measuring and comparing performance).
Note that each of the applications also has a tutorial (as a PDF and HTML) that can be found under the ‘Notes’ and ‘Information’ tabs, which are also posted under the Key Documents table below. AMPED1 - Introduction to Harvest Control Rules with AMPED.pdf AMPED2 - Introduction to Performance Indicators with AMPED.pdf AMPED3 - Comparing Harvest Control Rule Performance with AMPED.pdf
9. SC15 recommendations on Review of harvest control rules for skipjack tuna are provided in paragraphs 419 – 424 of the SC15 Summary Report (refer to HS-Ref.Doc-SC15-01 in the Key Documents below).
10. SC16 recommendations on Performance indicators, monitoring strategy, harvest control rules and management strategy evaluation are provided in Paragraphs 254 and 255 of the SC16 Summary Report (Refer to HS-Ref.Doc-SC16-01 in the Key Documents below).
1.2 Review of harvest control rules for South Pacific albacore
11. Initial work on the development of harvest strategies for South Pacific albacore has focused on developing an empirical management procedure (MP) that uses CPUE as the primary indicator of stock status (SC15-MI-WP-07, CPUE analysis for South Pacific albacore). Approaches for using CPUE as the primary indicator of stock status are under development.
12. At SC16, an information paper Retrospective CPUE forecasting of south Pacific albacore (SC16-MI-IP-04) was noted related to CPUE analysis.
Performance indicators for comparing management procedures
13. A key element of the harvest strategy approach is the development and use of a range of performance indicators for evaluating the relative performance of candidate management procedures (SC15-MI-WP-03, Performance indicators for comparing management procedures for South Paciﬁc albacore using the MSE modelling framework). The Commission noted the candidate performance indicators and monitoring strategies for South Pacific albacore commensurate with candidate management objectives for the southern longline fishery to be considered in the development of harvest strategies under CMM 2014-06 (WCPFC14 Summary Report, Attachment K, Table 1). The SC15 reviewed the proposed performance indicators for the southern longline fishery, which is shown in Table MI-01 of the SC15 Summary Report.
Management strategy evaluation framework
14. A Management Issues Theme paper SC15-MI-WP-08 (South Pacific albacore management strategy evaluation framework) describes the current status of the MSE framework for South Pacific albacore. It provides the initial development of the framework, focusing on two specific areas: i) the conditioning and selection of models for the operating model reference set, and ii) the design of candidate HCRs that use CPUE, and highlights areas for additional work.
15. The SC15 recommendations on the review of harvest control rules for South Pacific albacore are provided in paragraphs 441 – 445 of the SC15 Summary Report (refer to HS-Ref.Doc-SC15-01 in the Key Documents below).
16. SC16 noted an information paper HCR design considerations for South Pacific albacore (SC16-MI-IP-05) as an initial harvest control rule (HCR) design considerations for South Pacific albacore.
1.3 Initial list of performance indicators for tropical purse seine fisheries
17. The Commission accepted the suggested initial list of performance indicators for tropical purse seine fisheries as developed by the Small Working Group on Management Objectives at WCPFC13 for the purpose of the evaluation of harvest control rules (Attachment M, WCPFC13 Summary Report).
1.4 Accepted interim performance indicators for tropical purse seine fisheries
18. At WCPFC13, the Commission accepted the suggested initial list of performance indicators for tropical purse-seine fisheries as developed by the Small Working Group on Management Objectives at WCPFC13 for the purpose of the evaluation of harvest control rules. (This list is attached at WCPFC13 Summary Report Attachment M: WCPFC13 Att M (109.82 KB) ) (Ref: WCPFC13 Summary Report, paragraph 286)
1.5 Multi-species, mixed fishery modeling framework
19. An important consideration when developing harvest strategies is how to account for mixed fishery interactions. The SC15 considered a multi-species modeling framework as the four tuna stocks are caught by an overlapping mix of fisheries (SC15-MI-WP-04, Mixed fishery and multi-species issues in harvest strategy evaluations). The paper identifies two potential options for modelling mixed fisheries in the harvest strategy evaluations: i) Fully integrated modelling approach and ii) Hierarchical approach.
20. The SC15 recommendations on the multi-species modeling framework are provided in paragraphs 455 – 457 of the SC15 Summary Report (refer to HS-Ref.Doc-SC15-01 in the Key Documents below).
21. SC16 noted an information paper, Further consideration of the mixed fishery management strategy evaluation framework for WCPO tuna stocks (SC16-MI-IP-06) and some discussion was made at Online Discussion Forum.
II. Interim Objectives for Bigeye, Skipjack, and Yellowfin Tuna (from CMM 2018-01)
22. This measure is to create a bridge to the adoption of a harvest strategy for bigeye, skipjack, and yellowfin tuna stocks and/or fisheries in accordance with the work plan and indicative timeframes set out in the Agreed Work Plan for the Adoption of Harvest Strategies under CMM 2014-06, which includes the development of management objectives and target reference points. Taking into account the bridging role of this measure and the uncertainty framework for evaluating the impact of management measures on the bigeye stock, the Commission shall work towards achieving and sustaining the aims in paragraphs 12 to 14.
- Bigeye – Pending agreement on a target reference point the spawning biomass depletion ratio (SB/SBF=0) is to be maintained at or above the average SB/SBF=0 for 2012-2015.
- Skipjack – The spawning biomass of skipjack tuna is to be maintained on average at a level consistent with the interim target reference point of 50% of the spawning biomass in the absence of fishing, adopted in accordance with CMM 2015-06.
- Yellowfin – Pending agreement on a target reference point the spawning biomass depletion ratio (SB/SBF=0) is to be maintained at or above the average SB/SBF=0 for 2012-2015.
III. Limit Reference Points (LRPs)
23. WCPFC8 approved a number of the SC7 recommendations related to limit reference points
1) The agreed working definition for LRPs is to be based on the following principles:
- they define a state of the fishery that is considered to be undesirable and which management action should avoid;
- the probability of breaching an LRP should be very low;
- management actions should be taken before the fishery falls below or is at risk of falling below an LRP.
2) The hierarchical approach (as outlined in SC7-MI-WP-03) to identify key LRPs for key target species in the WCPFC is as follows:
A reliable estimate of steepness is available
FMSY and BMSY
Steepness is not known well, if at all, but the key biological (natural mortality, maturity) and fishery (selectivity) variables are reasonably well estimated.
FX%SPRo and either
The key biological and fishery variables are not well estimated or understood.
Bigeye: the LRP set at Level 2 with regard to the biomass-based LRP of 20%SBrecent,F=0, with deferral of a recommendation on the value of X% in the Level 2 fishing mortality-based LRP of Fx%SPR to the SC9 (SC8 recommendation)
Yellowfin: the LRP set at Level 2 with regard to the biomass-based LRP of 20%SBrecent,F=0, with deferral of a recommendation on the value of X% in the Level 2 fishing mortality-based LRP of Fx%SPR to the SC9 (SC8 recommendation)
South Pacific albacore: the LRP set at Level 2 with regard to the biomass-based LRP of 20%SBrecent,F=0, with deferral of a recommendation on the value of X% in the Level 2 fishing mortality-based LRP of Fx%SPR to the SC9 (SC8 recommendation)
Skipjack: the LRP for skipjack is set at Level 3, 20%SBrecent,F=0. (SC8 recommendation)
(note that SPR refers to the spawning-potential-per-recruit and SBrecent,F=0 refers to the estimated average spawning biomass over a recent period in the absence of fishing).
24. WCPFC10 endorsed that the time window to be used in the LRP 20%SBF=0,t1-t2 satisfy the following criteria:
- have a length of 10 years;
- be based on the years t1=ylast-10 to t2=ylast-1 where ylast is the last year used in the assessment; and
- the approach used for calculating the unfished biomass levels be based on scaled estimates of recruitment according to the stock recruitment relationship.
IV. Target Reference Points (TRPs)
4.1 WCPO bigeye and yellowfin tuna
25. At SC15, a risk-based TRPs for bigeye and yellowfin tuna were introduced (SC15-MI-WP-01, Minimum Target Reference Points for WCPO yellowfin and bigeye tuna consistent with alternative LRP risk levels, and multispecies implications) and the ‘minimum’ spawning-biomass-depletion-based TRPs for yellowfin and bigeye tuna were updated for WCPFC16 by applying the 2019 skipjack tuna stock assessment (WCPFC16-2019-15, Minimum target reference points for WCPO yellowfin and bigeye tuna consistent with alternative LRP risk levels, and multispecies implications). The SC15 recommendations on the review of WCPO bigeye and yellowfin tuna TRPs are provided in paragraphs 370 – 372 of the SC15 Summary Report (refer to HS-Ref.Doc-SC15-01 in the Key Documents below).
26. Noting the request from WCPFC16 to provide advice on the formulation of TRPs for bigeye and yellowfin tuna (paragraphs 273-275, WCPFC16 Summary Report), SC16 reviewed Further consideration of candidate target reference points for bigeye and yellowfin tuna in the WCPO (SC16-MI-WP-01) and requested the Scientific Services Provider undertake the analyses for bigeye and yellowfin tuna according to the criteria outlined in the Paragraph 211 of the SC16 Summary Report. Accordingly, the Scientific Services Provider provided a range of candidate TRPs for WCPO bigeye and yellowfin tuna (WCPFC17-2020-12).
4.2 WCPO skipjack Tuna
27. WCPFC12 agreed to [CMM on a TRO for WCPO Skipjack Tuna, doccode:27182], which shall initially be 50% of the estimated recent average spawning biomass in the absence of fishing, (SBF=0, t1-t2) calculated in a manner consistent with that detailed above for the LRP. This target reference point shall be an interim target reference point until it is reviewed in accordance with paragraph 8 of CMM 2015-06.
28. There have been several reviews through the Commission and subsidiary body meetings for the consideration of candidate TRPs for skipjack tuna. SC15 reviewed Current and projected stock status of skipjack tuna to inform consideration of target reference points (SC15-MI-IP-09/MOW3-WP-03), WCPFC16 reviewed an updated information on the Current and projected stock status of WCPO skipjack tuna to inform consideration of an updated target reference point (WCPFC16-2019-14), SC16 reviewed Updates to WCPO skipjack tuna projected stock status to inform consideration of an updated target reference point (SC16-MI-WP-02), and Updates to WCPO skipjack tuna projected stock status to inform consideration of an updated target reference point (WCPFC17-2020-11) for WCPFC17.
4.3 South Pacific albacore tuna
WCPFC15 agreed on an interim target reference point (TRP) for south Pacific albacore at 56% of spawning stock biomass in the absence of fishing (0.56 SBF=0) with the objective of achieving an 8% increase in catch per unit of effort (CPUE) for the southern longline fishery as compared to 2013 levels. If a future stock assessment indicates that this interim TRP will not result in the desired longline CPUE, then the interim TRP will be revised in order to meet this objective. The TRP shall be reviewed every 3 years, consistent with the SP albacore assessment schedule.
In order to manage the required reduction in catches, the timeline for achieving the interim target reference point shall be no later than 20 years.
 The method to be used in estimating the recent average spawning biomass in the absence of fishing shall be the same as that adopted by the Commission for the limit reference point, as described in paragraph 3 of CMM 2015-06.
 The proxy for CPUE will be the southern longline vulnerable biomass as estimated within the stock assessment.
As requested by WCPFC15, the SC15 reviewed performance of stochastic stock projections across the grid of 72 assessment models under future fishery scenarios to examine their performance in recovering the stock to the TRP (SC15-MI-WP-02, Alternative trajectories to achieve the South Pacific albacore interim TRP). This paper is updated for the WCPFC16 consideration (WCPFC16-2019-19). The SC15 recommendations on the alternative catch trajectories to achieve the South Pacific albacore interim TRP are provided in paragraphs 386 – 388 of the SC15 Summary Report (refer to HS-Ref.Doc-SC15-01 in the Key Documents below).
Reference Points adopted by the Commission as of 2018
V. Acceptable Risk Level of Exceeding LRP
At WCPFC12, the Commission noted that the SC10 had considered levels of risk associated with breaching the LRP within the range 5-20% and that the identification of acceptable risk is a management issue. The Commission agreed to identify the level of acceptable risk which should be applied to breaching a LRP for the key target species, noting that the UN Fish Stocks Agreement states that the risk of exceeding LRPs should be very low.
At WCPFC13 (Paragraph 296, WCPFC13 Summary Report), the Commission agreed to:
i) not specify, at this time, acceptable levels of risk of breaching the limit reference point for each stock;
ii) consider any risk level greater than 20 percent to be inconsistent with the LRP related principle in UNFSA (as referenced in Article 6 of the Convention) including that the risk of breaching limit reference points be very low; and
iii) determine the acceptability of potential HCRs where the estimated risk of breaching the limit reference point is between 0 and 20%.
VI. Stock Rebuilding Plan
North Pacific striped marlin
The Commission at WCPFC16 adopted the Interim Rebuilding Plan for North Pacific Striped Marlin (Attachment L, WCPFC16 Summary Report) WCPFC16-Attachment L - NPSM rebuilding plan.pdf
VII. Links to WCPFC MOW and HSW Workshop Materials and Outcomes
Four WCPFC workshops have been held on Management Objectives and Harvest Strategies from 2012 - 2014. These workshops were held as informal meetings of stakeholders with an interest in WCPO tuna fisheries, that were convened by the Commission to facilitate and support the development of harvest strategies by Commission Members. Links to the relevant meeting pages and reports:
- MOW1: 28 - 29 November 2012, Manila, Philippines: https://www.wcpfc.int/meetings/wcpfc-management-objectives-workshop
- MOW2: 28 November 2013, Cairns, Australia: https://www.wcpfc.int/meetings/wcpfc-management-objectives-workshop-2
- MOW3: 28 November 2014, Apia, Samoa: https://www.wcpfc.int/meetings/wcpfc-management-objectives-workshop-3
- MOW4/HSW: 30 November - 1 December, Bali, Indonesia: https://www.wcpfc.int/meetings/wcpfc-harvest-strategy-workshop
I. Interim Harvest Strategy for North Pacific Albacore Fishery
1. At NC6, and consistent with Article VI of the WCPFC Convention, Canada submitted a paper (WCPFC-NC6-DP02) on the development of a precautionary approach based fishery management regime for the northern stocks. Building on this paper, the Seventh Regular Session of the Northern Committee (NC7) agreed to a three-year work programme to develop a precautionary approach based management framework for North Pacific albacore.
2. The NC9 determined that it was best to delay discussions on the framework until the completion of the 2014 North Pacific albacore stock assessment. In July 2014, the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean (ISC) concluded that the North Pacific albacore stock is “healthy and that current productivity is sufficient to sustain recent exploitation levels, assuming average historical recruitment in both the short and long term”. The ISC also provided further advice regarding candidate limit and target reference points.
3. Based on the advice from the ISC, the NC10 recommended and the 11th regular session of the Commission (WCPFC11) adopted the Precautionary Management Framework for North Pacific Albacore. In December 2017, the Commission (WCPFC14) adopted the Interim Harvest Strategy for North Pacific Albacore Fishery as recommended by the NC13, which replaces the Precautionary Management Framework for North Pacific Albacore.
2. Interim management objective
4. The management objective for the North Pacific albacore fishery is to maintain the biomass, with reasonable variability, around its current level in order to allow recent exploitation levels to continue and with a low risk of breaching the limit reference point.
3. Biological reference points
5. Based on ISC’s stock assessment advice and following the hierarchical approach adopted by the Commission, North Pacific albacore is to be treated as a Level 2 stock. The following is based on an average recruitment scenario:
The limit reference point (LRP) for this stock is established at 20%SSBcurrent F=0. This LRP is consistent with the Annex II of the UN Fish Stocks Agreement (UNFSA) and recent WCPFC decisions on LRPs for the three tropical tuna species and South Pacific albacore, where 20%SSBcurrent F=0 was adopted. If this point is breached, management actions will be taken to return the stock to a predetermined level as outlined in the subsequent section on Decision Rules.
The target reference point (TRP) for this stock will be determined following a comprehensive analysis under a management strategy evaluation (MSE) approach as outlined in section 4 on “Future Work”. Historical fishing activity, anticipated fishing activity, and the source of increased fishing mortality will also be considered when evaluating a suitable TRP. Socioeconomic factors, as per UNFSA Article 6.3.c., will be further considered. The existing conservation and management measure (CMM) for the stock (WCPFC 2005-03) establishes through limits on current effort an overall management regime for the stock.
4. Decision rules
6. NC recommends a management strategy for the stock that ensures that the risk of the biomass decreasing below the LRP is low.
7. LRP rule: In the event that, based on information from ISC, the spawning stock size decreases below the LRP at any time, the NC will, at its next regular session or intersessionally if warranted, adopt a reasonable timeline, but no longer than 10 years, for rebuilding the spawning stock to at least the LRP and recommend a CMM that can be expected to achieve such rebuilding within that timeline. The NC will take into account historical fishing activity and the source of increased fishing mortality when developing management strategies to rebuild the stock, including in establishing effort reductions. The NC will further consider socioeconomic factors, as per UNFSA Article 6.3.c., as well as which the NC members, if any, contributed to exceeding the LRP.
5. Future work
8. This framework may be periodically reviewed and revised. To support such revisions, the NC endorses the ongoing development and implementation of an MSE for the stock and fishery, which would yield new information that would enhance the robustness of this framework.
II. Harvest Strategy for Pacific Bluefin Tuna Fisheries
1. Introduction and scope
9. This harvest strategy has been prepared in accordance with the Commission’s Conservation and Management Measure on Establishing a Harvest Strategy for Key Fisheries and Stocks in the Western and Central Pacific Ocean.
10. Although the provisions of this harvest strategy are expressed in terms of a single stock, they may be applied to multiple stocks as appropriate and as determined by the Northern Committee.
2. Management objectives
11. The management objectives are, first, to support thriving Pacific bluefin tuna fisheries across the Pacific Ocean while recognizing that the management objectives of the WCPFC are to maintain or restore the stock at levels capable of producing maximum sustainable yield, second, to maintain an equitable balance of fishing privileges among CCMs and, third, to seek cooperation with IATTC to find an equitable balance between the fisheries in the western and central Pacific Ocean (WCPO) and those in the eastern Pacific Ocean (EPO).
3. Reference points
12. Because steepness in the stock-recruitment relationship is not well known but the key biological and fishery variables are reasonably well estimated, the stock of PBF is to be treated as a Level 2 stock under the Commission’s hierarchical approach for setting biological limit reference points.
3.1 Rebuilding targets
13. Initial rebuilding target: The initial rebuilding target for the PBF stock size is the median SSB estimated for the period 1952 through 2014, to be reached by 2024 with at least 60% probability.
14. Recruitment scenario during initial rebuilding period: The low recruitment scenario (resampling from the relatively low recruitment period (1980-1989)) or the recent recruitment scenario (resampling from the last 10 years), whichever is lower, will be used for the ISC’s SSB projections until 2024 or until the SSB reaches the initial rebuilding target, whichever is earlier.
15. The ISC is requested to periodically evaluate whether the recruitment scenario used during the initial rebuilding period is reasonable given current conditions, and to make recommendations on whether a different scenario should be used. If ISC recommends a different scenario, this will be considered by the NC.
16. Second rebuilding target: The second rebuilding target for the PBF stock size is 20%SSBF=0, to be reached by 2034, or 10 years after reaching the initial rebuilding target, whichever is earlier, with at least 60% probability.
17. However, if: (1) the SSB reaches the initial rebuilding target earlier than 2024; (2) ISC recommends a recruitment scenario lower than the average recruitment scenario; and (3) the SSB projections indicate that the second rebuilding target will not be achieved on this schedule, the deadline for rebuilding may be extended to 2034 at the latest.
18. Also, if there is a recommendation from the Northern Committee that 20%SSBF=0 is not appropriate as the second rebuilding target, taking into account consideration from IATTC, scientific advice from ISC, IATTC or WCPFC SC, and socioeconomic factors, another objective may be established.
19. Recruitment scenario during second rebuilding period: After the initial rebuilding target is reached and until the second rebuilding target is reached, the recruitment scenario to be used for the SSB projections will tentatively be the average recruitment scenario (resampling from the entire recruitment period).
20. The ISC is requested to periodically evaluate whether the recruitment scenario used during the second rebuilding period is reasonable given current conditions, and to make recommendations on whether a different scenario should be used. If ISC recommends a different scenario, this will be considered by the NC.
3.2 Development of reference points
21. The Northern Committee will develop more refined management objectives as well as limit reference point(s) and target reference point(s) through MSE process specified in Section 6.
4. Acceptable levels of risk
22. Until the stock is rebuilt, the Northern Committee will recommend conservation and management measures as needed to ensure rebuilding in accordance with the probabilities specified in sections 2.1 and 5 for each of the two rebuilding targets.
23. Once the stock is rebuilt, in accordance with Article 6.1(a) of the Convention, the Northern Committee will recommend conservation and management measures as needed to ensure that any target reference point(s) (once adopted) are achieved on average in the long term, and ensure that the risk of the stock size declining below the B-limit (once adopted) is very low.
5. Monitoring strategy
24. The ISC will periodically evaluate the stock size and exploitation rate with respect to the established reference points and the report will be presented to the Scientific Committee. Until 2024, while the MSE is being developed (see section 6), the ISC is requested to conduct stock assessments in 2018, 2020 and 2022.
25. In order to cope with the adverse effects on the rebuilding of the stock due to drastic drops of recruitment: (1) all the available data and information will be reviewed annually, including recruitment data provided by the ISC and in National Reports; and (2) the ISC is requested to conduct in 2019, and periodically thereafter as resources permit and if drops in recruitment are detected, projections to see if any additional measure is necessary to achieve the initial rebuilding target by 2024 with at least 60% probability.
6. Decision rules
26. Harvest controls rules during initial rebuilding period: The interim harvest control rules below will be applied based on the results of stock assessments and SSB projections to be conducted by ISC.
(a) If the SSB projection indicates that the probability of achieving the initial rebuilding target by 2024 is less than 60%, management measures will be modified to increase it to at least 60%. Modification of management measures may be (1) a reduction (in %) in the catch limit for fish smaller than 30 kg (hereinafter called “small fish”) or (2) a transfer of part of the catch limit for small fish to the catch limit for fish 30 kg or larger (hereinafter called “large fish”). For this purpose, ISC will be requested, if necessary, to provide different combinations of these two measures so as to achieve 60% probability.
(b) If the SSB projection indicates that the probability of achieving the initial rebuilding target by 2024 is at 75% or larger, the WCPFC may increase their catch limits as long as the probability is maintained at 70% or larger, and the probability of reaching the second rebuilding target by the agreed deadline remains at least 60%. For this purpose, ISC will be requested, if necessary, to provide relevant information on potential catch limit increases.
27. Harvest controls rules during second rebuilding period: Harvest control rules to be applied during the second rebuilding period will be decided, taking into account the implementation of the interim harvest control rules applied during the initial rebuilding period.
28. The Northern Committee will, through MSE development process, develop decision rules related to the limit reference points once adopted including for the case of their being breached.
7. Performance evaluation
29. Until the stock is rebuilt, the Northern Committee will work with the ISC and the Scientific Committee and consult with the IATTC to identify and evaluate the performance of candidate rebuilding strategies with respect to the rebuilding targets, schedules, and probabilities.
30. The ISC is requested to start the work to develop a management strategy evaluation (MSE) for Pacific bluefin tuna fisheries in 2019 and have a goal of completing it by 2024.
31. To support development of the MSE, ISC is encouraged to identify at least two experts and the NC members are encouraged to provide additional funds for the ISC’s work on the MSE.
32. The Joint WG will start to discuss in 2018, and aim to finalize no later than 2019, guidelines for the MSE, including at least one candidate long-term target reference point (TRP), two candidate limit reference points (LRPs) and candidate harvest control rules (HCRs), which will be provided to the ISC. Those candidate TRPs, LRPs and HCRs will be tested and changed if appropriate during the MSE development process.
33. In preparation for the Joint WG meeting in 2019, the ISC is requested to organize workshops in early 2018 and 2019 to support the identification of specific management objectives, including level of risks and timelines. The workshops will include managers, scientists and stakeholders, taking into account any recommendations of the Joint WG, and the number of representatives should be relatively small, as it was for the MSE workshop for North Pacific albacore.
34. In evaluating the performance of candidate target reference points, limit reference points, and harvest control rules, the Northern Committee, in consultation with the ISC and the Scientific Committee, should consider the following criteria:
- Probability of achieving each of the rebuilding targets within each of the rebuilding periods (if applicable).
- Time expected to achieve each of the rebuilding targets (if applicable).
- Expected annual yield, by fishery.
- Expected annual fishing effort, by PBF-directed fishery.
- Inter-annual variability in yield and fishing effort, by fishery.
- Probabilities of SSB falling below the B-limit and the historical lowest level.
- Probability of fishing mortality exceeding FMSY or an appropriate proxy, and other relevant benchmarks.
- Expected proportional fishery impact on SSB, by fishery and by WCPO fisheries and EPO fisheries.
35. Recognizing that developing the operating model and other aspects of the MSE will take time and additional resources, and might require further dialogue between the Northern Committee, the ISC, and the IATTC, while the MSE is in development the ISC is requested to perform this work using the best means at its disposal.
 See the information provided by the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean (WCPFC-NC9-2013/IP-03) in response to a request made by the Northern Committee at its Eighth Regular Session (Attachment F, NC8 Summary Report).
 SSBF=0 is the expected spawning stock biomass under average recruitment conditions without fishing.
 WCPFC13 agreed that any risk level greater than 20 percent to be inconsistent with the limit reference point related principles in UNFSA (as references in Article 6 of the Convention) including that the risk of breaching limit reference points be very low.
III. Management Objectives for North Pacific Swordfish
36. The NC14 agreed to adopt the following management objectives for NP swordfish; “The management objective is to support thriving swordfish fisheries in the North Pacific while maintaining the stock size at levels capable of producing maximum sustainable yield. The Northern Committee will develop more refined management objectives.” In December 2019, the Commission accepted the recommendation from the NC15 on the harvest strategy for North Pacific swordfish fisheries (WCPFC16 – Attachment K). WCPFC16-Attachment K - HS for SWO.pdf