Science Advisory Report 2022/033

2021 Assessment of Northern Shrimp on the Eastern Scotian Shelf (SFAs 13–15)

Summary

• As of November 19,2021, 2,429 mt of the 2,600 mt Eastern Scotian Shelf (ESS) Northern Shrimp Total Allowable Catch (TAC) for 2021 had been landed.
• The total biomass estimate for ESS Northern Shrimp decreased by 29% from 29,87 mt in 2020 to 21,67 mt in 2021.
• The 2021 Spawning Stock Biomass (SSB; females) point estimate decreased by 29% to 13,041 mt and it is now below the Upper Stock Reference (USR, 14,558 mt). Based on the precautionary approach, the ESS Northern Shrimp stock is considered to be in the Cautious Zone.
• The TAC (2,600 mt) has been at the same level since 2017 to reflect declining fishable biomass (larger shrimp) and SSB (females only) resulting from the low recruitment contributions from the 2015 and 2016 year classes. The precautionary TAC helped to maintain both total and female exploitation since 2017; however, they have both increased in 2021 to values of 12% and 13%, respectively.
• Belly-bag index (Age 1 abundance) values for 2016 and 2017 were the lowest in the time series, suggesting future poor recruitment contributions. However, the values since 2018 show an increase in recruitment relative to these, and suggest better contributions in the next four years.
• The abundance index for both Age 2 and Age 4 ESS Northern Shrimp increased in 2021, which is consistent with the higher belly-bag Age 1 abundance index values found in 2020 (i.e., 2019 year class) and 2018 (i.e., 2017 year class).
• Ecosystem indicators were primarily influenced by temperature trends, as all three sympatric species trends (Snow Crab, Greenland Halibut, and Atlantic Cod recruitment) were not updated for 2021. The consistent increase in both bottom and sea-surface temperatures suggest that conditions are currently reaching unfavorable levels for cold-water species such as Northern Shrimp.
• The overall mean summary indicator decreased in 2021 and is in the yellow zone due to decreases in all four characteristic summaries representing abundance, productivity, fishing effects, and ecosystem characteristics. Twelve out of 24 indicators (4 not updated in 2021) describe adverse results for Northern Shrimp stock health.
• The 2021 SSB index places the stock in the Cautious Zone according to the DFO Precautionary Approach (PA). Further reduction of removal rates could stabilize catch rates, protect incoming recruitment essential to the fishery, and allow commercial biomass to rebuild.

This Science Advisory Report is from the December 13–14, 2021, Eastern Scotian Shelf Northern Shrimp Assessment. 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 2022/033 (PDF, 1,395 KB)

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