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Science Response 2021/025

Harvest Control Rule Update for Western Component Pollock (Pollachius virens) in NAFO Divisions 4Xopqrs5 for 2020

Context

Pollock (Pollachius virens) in Northwest Atlantic Fisheries Organization (NAFO) Divisions 4VWX5 comprise two population components: a slower-growing Eastern Component including Divisions 4V and 4W, as well as Subdivisions 4Xm and 4Xn, and a faster-growing Western Component (WC) including 4Xopqrs and Canadian portions of Division 5. The WC has been the main focus of past analytical assessments, but scientific advice on stock status and catch limits using Virtual Population Analysis (VPA) modeling became highly variable in the mid-2000s (Stone 2011). Consequently, the Canadian fishing industry recommended exploration of alternative approaches, which would provide more stability in future catch limits to allow for better business planning and a more stable fishery.

In 2011, fisheries managers and the fishing industry decided to manage WC Pollock using a risk-management approach and embarked on a Management Strategy Evaluation (MSE) process, with the help of government scientists and outside experts (DFO 2011). MSE is a technique to explicitly consider the uncertainty in stock assessment assumptions and models, and to compare the likely consequences to Management Objectives when a predetermined Management Procedure (MP) incorporating a Harvest Control Rule (HCR) is applied. The Pollock MP was selected on the basis of satisfying three medium-term objectives agreed upon for management of the resource, which relate to sustainability, catch levels, and the extent of annual catch changes. The MP model was built around an HCR that either increased or decreased future catch limits based on results from ongoing monitoring from the annual DFO Summer Research Vessel (RV) Survey. An Exceptional Circumstances Protocol was put in place to cover situations that fall outside the range for which the MP was simulation tested and, if necessary, to allow for some form of intervention.

This report provides an update to the 2019 analysis (DFO 2020) of the WC Pollock Harvest Control Rule and provides advice on the 2021–2022 Fishing Year (FY) catch limit generated by the Pollock MP and HCR using updated information from the 2020 DFO Summer RV Survey. It also describes current status with respect to the provisions in the Exceptional Circumstances Protocol. The HCR with updated monitoring data for 2020 generated a catch limit of 3,407 t for FY 2021–2022, down 20% from 4,259 t for FY 2020–2021. No exceptional circumstances were triggered in 2020.

This Science Response Report results from the Science Response Process of December 1-2, 2020, on the Stock Status Updates of Groundfish Stocks in the Maritimes Region.

Additional publications from this meeting will \be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

Accessibility Notice

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