Stock status update and harvest options for the Green Sea Urchin (Strongylocentrotus droebachiensis) fishery in British Columbia, 2024-2027

Abstract

British Columbia’s Green Sea Urchin (Strongylocentrotus droebachiensis) stock is assessed every three years using the assessment model developed by Perry et al. (2003). The last assessment was conducted in 2021 (DFO 2021a) and was used to inform the Pacifc Region’s Green Sea Urchin 2021-2024 Integrated Fishery Management Plan (IFMP) (DFO 2021b, 2022, 2023). The present assessment provides updated advice, based on the inclusion of new data, for the development of the next IFMP in 2024 and subsequent IFMPs until spring 2027. Fisheries and Oceans Canada (DFO) Fisheries Management has requested advice for the Green Sea Urchin fshery in British Columbia (BC), by spring 2024, on the following: 1. Evaluate stock status of Green Sea Urchins in Northeast (Pacifc Fisheries Management Areas - PFMAs: 11, 12, and 13) and Southeast Vancouver Island (PFMAs 14, 18, 19, and 20) using provisional reference points and density estimates derived from biological surveys within each management region. 2. Provide the ranges of sustainable harvest options for the commercial harvest regions (PFMAs 11, 12, 13, 14, 18, 19, and 20). 3. Analyze index site survey data (PFMAs 12 and 19) and present the recent trends in the local populations and population structure for Green Sea Urchins. 4. Examine and identify uncertainties in the data and methods. 5. Provide recommendations for additional research or stock assessment programs. This assessment updates previously published time series data and provides new harvest options for the 2024-2025 to 2026-2027 Green Sea Urchin fshery. Methods remain largely unchanged since 2003 and a Bayesian biomass dynamic model continues to be used in the assessment of BC’s Green Sea Urchin stock (Perry et al. 2003, 2006; Zhang and Perry 2005; Waddell et al. 2010; DFO 2015, 2016, 2018a, 2021a). This assessment updates the model results with the most recently available commercial catch (fshery-dependent) and biological dive survey (fshery-independent) information. Provisional reference points compliant with the DFO’s Fishery Decision-Making Framework Incorporating the Precautionary Approach (DFO Precautionary Approach; DFO 2009) were established (DFO 2018a) and subsequently implemented in the fshery (DFO 2018b). Using these reference points, Green Sea Urchin stock status can be estimated in the regions of Northeast Vancouver Island (PFMAs 11, 12, and 13) and Southeast Vancouver Island (14, 18, 19, and 20); the two regions where the long-term index sites are located (PFMAs 12 and 19). This Science Response Report results from the May 23, 2024 regional peer review on Stock Status Update and Harvest Options for the Green Sea Urchin (Strongylocentrotus droebachiensis) Fishery in British Columbia, 2024-2027.