The International Pacific Halibut Commission (IPHC) conducted the 93rd Session of its Interim Meeting at the Grand Hyatt Seattle in Seattle, Washington on 28 and 29 November 2017. The IM093 report, documents, presentations and webcast recordings are posted on the Commission’s website at http://iphc.int/meetings-and-events/interim-meeting.html.
Fishery-Independent Setline Survey
This was the fourth year of the IPHC’s six-year fishery-independent setline survey (FISS) expansion program, with 108 additional stations fished in IPHC Regulatory Area 2A and 113 in 4B during the 2017 setline survey, with almost 1500 stations coastwide. For 2018, the IPHC plans to undertake expansions into Regulatory Areas 2B and 2C, adding approximately 158 new stations to the standard setline survey grid.
The space-time modeling approach introduced in 2016 was used for the analysis of IPHC setline survey data. This modeling approach is a clear improvement over the previous empirical method as it makes greater use of the information within the data, and better accounts for uncertainty in the estimation.
The 2017 Stock Assessment
This year’s stock assessment is based on an ensemble of four models used since 2014. Recruitment cohorts from 2006 through 2013 are estimated to be smaller than those from 1999-2005, indicating a high probability of decline in both the stock and fishery yield as recent recruitments become increasingly important to the age range over which much of the harvest and spawning takes place.
A summary of the preliminary 2017 stock assessment results is presented in paper IPHC-2017-IM093-08 on the IPHC website at http://iphc.int/meetings-and-events/interim-meeting/im093-documents.html, and will be updated for the 94th Annual Meeting.
Draft Harvest Decision Table for 2018
The IPHC Secretariat’s provisional harvest advice is prepared in the form of a decision table for the Commission’s consideration as it sets the annual catch limits. This provisional harvest decision table (Table 1, next page) presents estimates of risk over a range of potential harvest options for 2018 (the columns) as measured by different stock and fishery metrics (the rows), and will be updated and presented again at the Annual Meeting (AM094) in January 2018.
The orientation of this table has changed from previous analyses in order to make the comparison of additional metrics easier and to increase consistency with the results produced from the IPHC Management Strategy Evaluation.
Values in the table represent the probability, in “times out of 100,” of a particular risk. Total removals include all Pacific halibut mortality caused by humans, i.e., all removals except natural mortality. The center column (shown as wider than the others) represents the application of the current interim management procedure to the stock assessment results, corresponding to an average Spawning Potential Ratio (SPR) of F46. Alternative metrics of performance, as well as different increments of total removals, may be considered in the Commission’s decision-making process.
Interim Harvest Strategy Policy
In addition to adopting an average SPR of F46 as the reference level of coastwide fishing intensity to be used as an interim management procedure while a harvest strategy policy is being developed, the Commission directed the IPHC Secretariat to provide for future management decisions to be based on Total Constant Exploitation Yields (TCEY), rather than Fishery Constant Exploitation Yields (FCEY). This allows catch limits to be more directly comparable across IPHC Regulatory Areas.
The combination of the stock distribution from the 2017 O32 fishery-independent setline survey catch and relative target harvest rates among IPHC Regulatory Areas results in the target distribution for the annual TCEY shown in Table 2.
Pacific halibut mortality projected for 2018 based on the reference SPR (46%) and the target TCEY distribution, for each component of the TCEY (each sector) in each of the IPHC Regulatory Areas, is presented in Table 3.
The reference projection TCEY results for 2018 represent a reduction of 21% from the reference level calculated based on the 2016 stock assessment, and 24% from the TCEYs adopted for 2017. This comparison is shown in Table 4.
A summary of the Regulatory Area-specific mortality projections for 2018 based on the interim management procedure and other alternatives is presented in paper IPHC-2017-IM093-09 on the IPHC website at http://iphc.int/meetings-and-events/interim-meeting/im093-documents.html.
Table 1. Preliminary harvest decision table for 2018. Columns correspond to yield alternatives and rows to risk metrics. Values in the table represent the probability, in “times out of 100” (or percent chance) of a particular risk.
Table 2. IPHC Regulatory Area stock distribution from the 2017 O32 fishery-independent setline survey catch, IPHC Regulatory Area-specific relative target harvest rates, and resulting 2018 target TCEY distribution based on the IPHC’s current interim management procedure.
Table 3. Pacific halibut mortality projected for 2018 based on the reference SPR (46%) and interim management procedure for TCEY distribution. All values reported in millions of net pounds.
Table 4. Comparison of TCEY values. All values reported in millions of net pounds.
Regulatory Proposals for 2018, including Catch Limit Proposals
A total of twenty-two regulatory proposals were considered at the IM093, five from the IPHC Secretariat, three from the United States of America (NOAA-Fisheries), and fourteen from other stakeholders. All proposals will be further considered at the 94th Session of the IPHC Annual Meeting (AM094) to be held in January 2018.
The Commission invites additional regulatory proposals, including proposals for catch limits, as well as public comment to be considered at the 94th Annual Meeting. Proposals or comments should be submitted to the IPHC Secretariat no later than 23 December 2017 using the submission form on the IPHC website (http://iphc.int/meetings-and-events/annual-meeting/reg-proposals.html).
Report of the 93rd Session of the IPHC Interim Meeting (IM093)
The report of the 93rd Session of the IPHC Interim Meeting (IM093) is available on the IPHC website (http://iphc.int/meetings-and-events/interim-meeting.html).
Looking Ahead to the 2018 Annual Meeting (AM094)
The 94th Session of the IPHC Annual Meeting (AM094) will be held 22-26 January 2018 at the Hilton Portland Downtown in Portland, Oregon, USA. New this year, the meeting will require attendees to pre-register. Please follow the Annual Meeting registration link at https://iphcam094.eventbrite.com.
The meeting is scheduled to open on Monday with presentations on the fishery, the 2017 stock assessment, and the harvest decision table, and conclude on Friday. All sessions are open to the public and webcast.
The most up-to-date information regarding the 2018 Annual Meeting (AM094) can be found on the Annual Meeting page of the Commission's website (http://www.iphc.int/meetings-and-events/annual-meeting.html). The website will be updated regularly with new information as the meeting date approaches, including meeting documents, webcast information, and presentations.
The IPHC has reserved a block of rooms at the Hilton Portland Downtown (921 SW Sixth Avenue, Portland, OR 97204) at the rate of $169 USD. The link to the hotel reservation site is located on the event registration page (https://iphcam094.eventbrite.com). The group rate is available until December 27, 2017.
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David T. Wilson, Ph.D.
Executive Director, IPHC
Phone: (206) 634-1838
Fax: (206) 632-2983