Science Advisory Report 2021/031

Stock Assessment of NAFO Subdivision 3Ps Cod

Summary

• The stock was assessed using an integrated state-space model, which incorporates landings and catch at age (1959-2019), time-varying natural mortality informed by trends in cod condition, and includes abundance indices from research surveys using bottom trawls conducted by Canada (1983-2005, 2007-19), France (1978-91), industry (Groundfish Enterprise Allocation Council [GEAC],1998-2005), and standardized catch rate indices from the Sentinel gillnet and line-trawl surveys (1995-2019). There was no 2020 Canadian bottom trawl survey.
• Spawning Stock Biomass (SSB) at January 1, 2021 is projected to be 25 kt (18 kt 35 kt) with an assumed catch of 2,702 t in 2020. The stock is in the Critical Zone (38% of the Limit Reference Point (LRP); 27-53%) as defined by the DFO Precautionary Approach (PA) Framework. The probability of being below the LRP is >99.9%. The stock has been below the LRP since the early 2000s.
• The estimated fishing mortality rate (F) for ages 5-8 declined from 0.16 in 2015 to 0.11 in 2019. With an assumed catch of 2,702 t in 2020, F is projected to be 0.07 (0.05-0.09) in 2020.
• Natural mortality (M) for ages 5-8 has increased during the last decade, reaching 0.43 (0.35-0.52) in 2019.
• Recruitment (age 2) estimates up to 2019 have been below the long-term average since the mid-1990s.
• Projection of the stock to 2023 was conducted assuming fishery removals to be within +/- 60% of an assumed catch of 2,702 t for 2020 and with no catch. Under these scenarios, there is a probability >99% that the stock will remain below the LRP between 2021 and the beginning of 2023.
• The probability of stock growth to 2023 ranges between 39% and 78% across catch scenarios (+/- 60% of current levels), and is 88% when there are no removals.
• Natural mortality plays an important role in projections for this stock. If natural mortality rates are appreciably different from those used, projected outcomes will differ from values reported above.
• Bottom temperatures in Subdiv. 3Ps remained above normal between 2009 and 2019, but no data were available for 2020. No zooplankton data were available for 2019 and 2020. Satellite imagery indicates that the timing and magnitude of the spring phytoplankton bloom were normal in 2020, after two consecutive years of early onset and above-normal production.
• Ongoing warming trends, together with an increased dominance of warm water fishes, indicate that this ecosystem continues to experience structural changes. Reduced condition is indicative of diminished productivity in Subdiv. 3Ps cod.
• Consistency with the DFO decision-making framework incorporating the PA requires that removals from all sources must be kept at the lowest possible level until the stock clears the Critical Zone.

This Science Advisory Report is from the November 2-6, 2020 regional advisory meeting on the Assessment of Northwest Atlantic Fisheries Organization (NAFO) Subdivision 3Ps Atlantic Cod. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

Science Advisory Report 2021/031 (PDF, 1,031 KB)

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