Stock Status Update with Application of Management Procedures for Pacifc Herring (Clupea pallasii) in British Columbia : Status in 2024 and forecast for 2025

Abstract

Pacifc Herring (Clupea pallasii) abundance in British Columbia (BC) is assessed using a statistical catch-age (SCA) model (Martell et al. 2011). In 2017, the Pacifc Herring stock assessment included updates to the SCA model, a bridging analysis to support these changes (Cleary et al. 2019), and estimation of stock productivity and current stock status relative to the new limit reference point (LRP) of 0.3SB0 (Kronlund et al. 2017), where SB0 is estimated unfshed spawning biomass. In 2022, upper stock reference (USR) point options were introduced for the major stock assessment regions (SARs) and this assessment includes estimates of stock status relative to productive period USRs (DFO 2023a). The overall structure of the SCA model has not changed since 2017. In 2016, Fisheries and Oceans Canada (DFO) committed to renewing the current management framework to address a range of challenges facing Pacifc Herring stocks and fsheries in BC. Renewal of the management framework included engaging in a management strategy evaluation (MSE) process to evaluate the performance of candidate management procedures against a range of hypotheses about future stock and fshery dynamics. As part of the MSE process, a Canadian Science Advisory Secretariat (CSAS) regional peer review occurred in 2018, where performance of Pacifc Herring management procedures (MPs) were assessed against conservation objectives for the Strait of Georgia (SoG) and West Coast of Vancouver Island (WCVI) SARs (DFO 2019). Steps included operating model (OM) development (Benson et al. 2022), ftting the OM to Pacifc Herring stock and fshery monitoring data (OM conditioning), and closed-loop simulations of MP performance for alternative future natural mortality scenarios. In 2019, DFO initiated the MSE process for the Haida Gwaii (HG), Prince Rupert District (PRD), and Central Coast (CC) SARs (DFO 2020a). Updates to MP evaluations were then conducted for SoG and WCVI SARs in 2020 (DFO 2021a) and for PRD, CC, SoG, and WCVI in 2023 (DFO 2022, 2023a). This assessment includes new science advice on choice of USR points for four of the fve major Pacifc Herring SARs: HG, PRD, CC, and WCVI. Note that the SoG SAR is assessed in DFO (2025) using a new modelling framework (Johnson et al. 2024). An analysis of USR options for PRD, CC, SoG, and WCVI was completed in 2022 (DFO 2023a) and provisional USRs based on productive periods identifed for each SAR was implemented in the 2022/23 Integrated Fisheries Management Plan (IFMP). Since initiation of the Pacifc Herring MSE process, MP evaluations have been included in the annual stock assessment as follows: 1. The 2018 stock assessment included MP recommendations for the SoG and WCVI SARs (DFO 2019). 2. The 2019 stock assessment included MP recommendations for the HG, PRD, and CC SARs, and implemented MP recommendations from previous years for the SoG and WCVI SARs (DFO 2020b). 3. The 2020 stock assessment included updated MP recommendations for the SoG and WCVI SARs, and implemented MP recommendations from previous years for the HG, PRD, and CC SARs (DFO 2021a). 4. The 2021 stock assessment included updated MP recommendations for the PRD and CC SARs, and implemented MP recommendations from previous years for the SoG and WCVI SARs (DFO 2021b). 5. The 2022 stock assessment included updated MP recommendations for the PRD, CC, SoG, and WCVI SARs (DFO 2022). 6. The 2023 stock assessment implemented MPs from previous years for the PRD, CC, SoG, and WCVI SARs (DFO 2024). Note that MPs for HG and SoG are not currently updated through this process. Management measures to support long-term recovery of HG herring are being developed through the HG rebuilding plan process.¹MPs for SoG are updated in DFO (2025) using methods from Johnson et al. (2024). This 2024 stock assessment includes MP recommendations for PRD, CC, and WCVI, derived in 2022 by updating herring OM conditioning (Benson et al. 2022) using the historic stock and fshery data from 1951 to 2021 (DFO 2022). There are no new MP evaluations for 2024 (all probability metrics refect the MP evaluations presented in 2022). Fisheries and Oceans Canada (DFO) Pacifc Fisheries Management Branch requested that DFO Pacifc Science Branch assess the status of British Columbia (BC) Pacifc Herring stocks in 2024 and recommend harvest advice for 2025 using simulation-tested MPs to inform the development of the 2024/2025 IFMP, where appropriate. Estimated stock trajectories, current status of stocks for 2024, management procedure options, and harvest advice recommendations from those MPs for 2025 refect methods of Cleary et al. (2019) and Benson et al. (2022) and, where applicable, recommendations from the aforementioned 2018, 2019, 2020, 2021, 2022, and 2023 MSE analyses (Section “Application of MPs and harvest options for 2025”). This Science Response results from the regional peer review of September 23, 2024 on the 2024/2025 Pacific Herring Stock Assessment, Forecast of Mature Stock Biomass, and Harvest Options for 2025 (HG, PRD, CC, WCVI). ¹Haida Gwaii ’íináang | iinang Pacific Herring: An ecosystem overview and ecosystem-based rebuilding plan. Approved by the Minister of Fisheries and Oceans, the Council of Haida Nation and Parks Canada. April 2024. In Press.