Terms of Reference

Framework Review for 4X5Y Haddock: Part 2 - Modelling Review

Regional Peer Review - Maritimes Region

March 20-21, 2024

St. Andrews, NB

Chairperson: Tara McIntyre

Context

Haddock (Melanogrammus aeglefinus) are caught as part of a multi-species groundfish fishery concentrated on the western Scotian Shelf (SS) and in the Bay of Fundy (BoF) in the Northwest Atlantic Fisheries Organization (NAFO) Divisions 4X5Y. In 2017, a virtual population analysis (VPA) model with fixed natural mortality time blocks on older fish, was chosen to provide catch advice (Wang et al. 2017). In 2018, projections from the VPA model showed large retrospective patterns and there was a mismatch between the model predicted biomass and the survey biomass (Finley et al. 2018). The VPA model has therefore not been used to provide catch advice or estimate stock status since 2018, and stock status updates have been provided qualitatively by comparing the survey biomass index to 40% and 80% of the 1985-2020 time series median. The intent of this framework review, initiated by DFO Maritimes Science, is to develop an analytical modeling framework that can be used to evaluate the performance of management procedures for the 4X5Y Haddock fishery. The first of a series of peer review meetings for this framework was a review of the data inputs and was completed in October 2023 (Barrett and Barrett In Prep). The objective of this second meeting will be to review the structural assumptions and fits of population dynamics models conditioned to the data inputs that will form the basis for an operating model (OM) or a suite of OMs that will be used in the evaluation of the performance of management procedures for the 4X5Y Haddock fishery.

Objectives

The specific objectives of this second peer review meeting are to:

• Identify a population dynamics model to be used in a base operating model for characterizing the population dynamics of the stock.
• Evaluate the influence of the main uncertainties in population or fishery dynamics (e.g., stock origin of the catch in south of NAFO area 4Xp, distribution assumptions of the DFO survey index, fishery selectivity shape) on model performance and fit (sensitivity runs).
• Identify uncertainties to which catch advice should be robust, that can be included in additional OMs.
• Explore potential ecosystem covariates on model parameters.

Expected Publications

• Research Document

Expected Participation

• DFO Science
• DFO Resource Management
• Provinces of Nova Scotia and New Brunswick
• Academics
• Indigenous communities/organizations
• Fishing industry
• Environmental non-government organizations
• NOAA

References

• Barrett, T.J., and Barrett M.A. (In Prep). 2024 4X5Y Haddock Framework: Data Inputs. DFO Can. Sci. Advis. Sec. Res. Doc.
• Finley, M., Wang, Y., and Stone, H.H. 2018. Assessment of 4X5Y Haddock (Melanogrammus aeglefinus) in 2016. DFO Can. Sci. Advis. Sec. Res. Doc. 2018/041. iv + 54 p.
• Wang, Y., Stone, H. H., and Finley, M. 2017. 4X5Y Haddock 2016 Framework Assessment: Modelling and Reference Points. DFO Can. Sci. Advis. Sec. Res. Doc. 2017/026.