Stock Assessment

Stock Assessment

The IPHC conducts an annual stock assessment, using data from the fishery-independent setline survey (FISS), the commercial Pacific halibut and other fisheries, as well biological information from its research program. The assessment includes the Pacific halibut resource in the IPHC Convention Area, covering the Exclusive Economic Zones of Canada and the United States of America. Data sources are updated each year to reflect the most recent scientific information available for use in management decision making.

 

Most recent stock assessment

The 2018 stock assessment relied on an ensemble of four population dynamics models to estimate the probability distributions describing the current stock size, trend, and demographics. The ensemble is designed to capture both uncertainty related to the data and stock dynamics (due to estimation) as well as uncertainty related to our understanding of the way in which the Pacific halibut stock functions and is best approximated by a statistical model (structural uncertainty).

Stock assessment results are used as inputs for harvest strategy calculations, including catch tables for the upcoming year that reflect the IPHCs harvest strategy policy and other considerations, as well as the harvest decision table which provides a direct tool for the management process. The harvest decision table uses the probability distributions from short-term (three year) assessment projections to evaluate the trade-offs between alternative levels of potential yield (catch) and the associated risks to the stock and fishery.

The 2018 stock assessment documents:

Document Title PDF PPT Availability
IPHC-2019-AM095-08 Overview of data sources for the Pacific halibut stock assessment, harvest policy, and related analyses (I. Stewart & R. Webster)  pdf icon ppt 20 Dec 2018
IPHC-2019-AM095-09 Assessment of the Pacific halibut (Hippoglossus stenolepis) stock at the end of 2018 (I. Stewart & A. Hicks) pdf icon ppt 17 Dec 2018
IPHC-2018-IM094-08 Rev_1 Summary of the data, stock assessment, and harvest decision table for Pacific halibut (Hippoglossus stenolepis) at the end of 2018 (I. Stewart, A. Hicks, R. Webster & D. Wilson) pdf icon ppt 25 Oct 2018
20 Nov 2018
 

Peer Review

Peer review of the IPHC Stock Assessment currently takes two forms: 1) Scientific Review Board - an annual peer review process, and 2) External peer review – a periodic peer review by an external independent reviewer approximately every three (3) years.

Scientific Review Board

The Scientific Review Board (SRB) is a small group of fisheries science experts and provides an independent scientific peer review of Commission science/research proposals, programs, and products, including but not limited to Stock assessment.

The SRB meets twice-annually for 2.5 to 3 days to peer review the core IPHC science streams. While early meetings of the SRB were focused solely on reviewing the stock assessment inputs, modelling and results, in recent years the IPHC Secretariat’s scientific output, in terms of volume and complexity have increased substantially.

All SRB documents and reports containing recommendations regarding the stock assessment are available on the IPHC website: Scientific Review Board.

External Peer Review

At the 95th Session of the IPHC Annual Meeting (AM095) in January 2019, the Commission agreed to implement an additional process of periodic external peer review of the IPHC Stock Assessment. The following is a list of key documents relating to the 2019 external peer review:

Document Title PDF Availability
  Independent Peer Review for the 2019 IPHC Stock Assessment - Prepared by Kevin Stokes 2019 EOI 02 August 2019
 

Previous stock assessments

Stock assessment documents from prior years:

Document Title PDF PPT Availability
IPHC-2018-AM094-08 Summary of the data, stock assessment, and harvest decision table for Pacific halibut (Hippoglossus stenolepis) at the end of 2017 (I. Stewart, A. Hicks, R. Webster & D. Wilson) PDF icon PPT icon 19 Dec 2017
IPHC-2018-AM094-09 Overview of data sources for the Pacific halibut stock assessment, harvest policy, and related analyses. (I. Stewart & R. Webster) pdf.gif PPT icon 21 Dec 2017
IPHC-2017-AM093-07 Assessment of the Pacific halibut stock at the end of 2016 (I. Stewart and D. Wilson) PDF.gif   11 Jan 2017
IPHC-2016-RARA26-P279 Overview of data sources for the Pacific halibut stock assessment and related analyses (I. Stewart) PDF.gif   05 Jan 2017
IPHC-2016-BB-P136 Assessment of the Pacific halibut stock at the end of 2015 (I. Stewart, C. Monnahan, and S. Martell) PDF.gif   25 Jan 2016
IPHC-2016-BB-P047 Overview of data sources for the Pacific halibut stock assessment and related analyses (I. Stewart and C. Monnahan) PDF.gif   25 Jan 2016
IPHC-2015-RARA25-P623 Appendix: Development of the 2015 stock assessment (I. Stewart and S. Martell) PDF.gif   2015