Stock Assessment

The 2022 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 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 2022 stock assessment documents:

The 2022 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.

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 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:

Stock assessment documents from prior years: