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 2024 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 (estimation) and stock dynamics (process) 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).
Stock assessment results are used as inputs for harvest strategy calculations, including mortality 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 2024 stock assessment documents:
Document
Title
Availability
IPHC-2025-SA-01
Assessment of the Pacific halibut (Hippoglossus stenolepis) stock at the end of 2024 (I. Stewart & A. Hicks)
19 Dec 2024
Stock Assessment Model Input Files
The 2024 stock assessment included an ensemble of 4 individual assessment models. Below are the raw input data files for each of the four models in the format required by stock synthesis (Methot, R.D., and Wetzel, C.R. 2013. Stock synthesis: A biological and statistical framework for fish stock assessment and fishery management. Fish. Res. 142(0): 86-99. doi: http://dx.doi.org/10.1016/j.fishres.2012.10.012).
Please contact the IPHC Secretariat (secretariat@iphc.int) for more information about the contents of these files and for permission to use them for any analysis.
Document
Title
Availability
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) meets twice annually and provides an independent scientific peer review of stock assessment and associated inputs (among other tasks).
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 meeting website under “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:
Previous Stock Assessments
Stock assessment documents from prior years:
