Science Response 2019/018
Harvest Control Rule Update for Western Component Pollock (Pollachius virens) in NAFO Divisions 4Xopqrs5
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 Area 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 and Oceans Canada (DFO) 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). The MSE is an approach 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 a 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.
In January 2017, Resource Management and Industry asked that the 2015 DFO Summer RV Survey index value be considered a missing value to reflect concerns that the point was not representative of the state of the stock (DFO 2018). Further, as the HCR uses the previous year’s quota as a starting point for the following year, the actual 2016/2017 quota of 3,081 t was used in the HCR to generate advice for 2017/2018. This approach was supported by members of the Scotia Fundy Groundfish Advisory Committee (SFGAC) as it stayed as close as possible to the HCR for this stock, while reflecting the increasing trends seen in the DFO Summer RV Survey index, the fishery, and U.S. surveys. Following this approach, the HCR quota for Fishing Year (FY) 2017/2018 was set at 3,697 t.
This report provides an update to the 2017 analysis (DFO 2018) of the Western Component Pollock Harvest Control Rule and provides advice on the FY 2019/2020 catch limit generated by the Pollock MP and HCR using updated information from the 2018 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 2018, generated a catch limit of 5,324 t for FY 2019/2020, up 20% from 4,437 t for FY 2018/2019. The DFO Summer RV Survey biomass index decreased from 13.16 kg/tow in 2017 to 12.97 kg/tow in 2018 and did not trigger the exceptional circumstance provision of the DFO Summer RV Survey biomass index being < 6 kg/tow for two consecutive years and the Survey Index Ratio being < 0.2.
This Science Response Report results from the Science Response Process of December 6, 2018, on the Status Update of the Western Component Pollock Management Strategy Evaluation.
Accessibility Notice
This document is available in PDF format. If the document is not accessible to you, please contact the Secretariat to obtain another appropriate format, such as regular print, large print, Braille or audio version.
- Date modified: