Science Response 2018/054

Stock Status Update for Green Sea Urchin (Strongylocentrotus droebachiensis) in British Columbia and Harvest Options for the Fishery in 2018 to 2021

Context

British Columbia’s Green Sea Urchin (Strongylocentrotus droebachiensis) stocks are assessed every two to three years using the assessment model developed by Perry et al. (2003). The last assessment was conducted in 2016 (DFO 2016b) and used to inform the Pacific Region’s Green Sea Urchin 2016-2018 Integrated Fishery Management Plan (IFMP) (DFO 2016a). The present assessment provides updated advice, based on the inclusion of new data, for the development of the next IFMP in 2018.

Fisheries and Oceans Canada (DFO) Fisheries Management has requested advice for the Green Sea Urchin fishery in British Columbia (BC), by spring 2018, on the following:

1. candidate reference points for Green Sea Urchins consistent with the DFO Precautionary Approach;
2. current status of Green Sea Urchins relative to the suggested reference points;
3. ranges of sustainable harvest options and their associated risks for the commercial quota areas;
4. recent trends in the local populations and population structure for Green Sea Urchins;
5. uncertainties in the data and methods; and,
6. additional research or stock assessment programs.

This assessment updates previously published time series data and provides new harvest options for the 2018-2019 to 2020-2021 Green Sea Urchin fishery. Methods remain unchanged, employing a Bayesian biomass dynamic model used in the assessment of BC’s Green Sea Urchin stocks since 2003 (Perry et al. 2003, Zhang and Perry 2005, Perry et al. 2006, Waddell et. al. 2010, DFO 2014, DFO 2016b). This assessment updates the model results with the most recently available commercial catch (fishery-dependent) and survey (fishery-independent) information.

The reference points used for Green Sea Urchins in BC since 2003, although precautionary, do not enable the estimation of stock status relative to the stock zones, and are therefore not considered compliant with the DFO Precautionary Approach (PA) (DFO 2009). This assessment provides candidate reference points that are based on density rather than a maximum sustainable yield (MSY) metric, and allow assessment of stock status relative to the three zones, as identified in the DFO PA: healthy, cautious and critical.

This Science Response results from the Science Response Process of April 2018 on Stock Status Update and Harvest Options for the Green Sea Urchin (Strongylocentrotus droebachiensis) fishery in British Columbia, 2018-2021.

Complete document (PDF, 2,752 KB)

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