Framework review for 4X5Y Haddock : part 1 - review of the data inputs

Abstract

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. This document is a review of the data inputs for the modeling framework for the 4X5Y Haddock stock that is expected to be completed in 2024. Stock structure was reviewed and an evaluation of spatial differences in growth was conducted to identify appropriate boundaries for the separation of the data inputs for faster growing Haddock in the BoF and slower growing Haddock on the SS. Fleet structure and the spatial and temporal distribution of catches were reviewed. The method to estimate catch-at age was revised and the catch history was estimated for two alternative catch scenarios that assume catches in the south of Fisheries and Oceans (DFO) statistical unit area (DFO unit area) 4Xp are from the 5Z Haddock stock. These catch scenarios can be used to capture uncertainty in stock mixing and to explore the potential causes of retrospective patterns in model fits. The DFO summer ecosystem survey biomass index for 4X5Y Haddock was estimated based on a weighted-mean biomass and a weighted-mean biomass assuming a delta-lognormal distribution. These two indices will be evaluated in sensitivity analyses when models are fit. The fishery and survey length-at-age, weight-at-age, age-length keys, and the survey maturity-at-age were estimated by region (BoF and SS) using methods to fill missing data. Stomach contents data and a number of ecosystem indicators from the DFO Atlantic Zonal Monitoring Program were identified to be considered for exploring ecosystem considerations for the stock.