Research Document 2024/002

Assessing the Status of the Cod (Gadus morhua) Stock in NAFO Subdivision 3Ps in 2019

By Ings, D.W., Varkey, D., Babyn, J., Regular, P.R., Champagnat, J., Kumar, R., Morgan, M.J., Healey, B.P., Rideout, R.M., and Vigneau, J.

Abstract

The status of the Atlantic Cod (Gadus morhua) stock in the Northwest Atlantic Fisheries Organization (NAFO) Subdivision 3Ps was assessed during a Fisheries and Oceans Canada (DFO) Regional Peer Review Process meeting held November 19–22, 2019.

Total landings for the 2018–19 management year (April 1–March 31) were 4,742 t or 79% of the Total Allowable Catch (TAC).

Survey abundance and biomass estimates from the DFO research vessel (RV) spring survey were below average during 2016 to 2019. Sentinel gillnet catch rates have been very low and stable since 1999. Sentinel line-trawl catch rates have been below average for the past eight years and the 2018 catch rate was the lowest in the time-series.

A new integrated state space model resulting from the 2019 3Ps Cod Framework was used to assess the status of the stock and estimate fishing mortality.

A new biomass limit reference point (LRP) was determined for the stock based on the relationship between spawning stock biomass (SSB) and recruitment estimated from the model. The LRP is 66,000 t of SSB. Using the new assessment model, SSB at January 1, 2020, is estimated to be 16 kt (12 kt–21 kt). The stock is in the Critical Zone (24% of B_lim [18–32%]) as defined by the DFO Precautionary Approach (PA) Framework. The probability of being below B_lim is >99.9%. The estimated fishing mortality rate (ages 5–8) has ranged between 0.12 and 0.21 since 2010 and in 2019 was 0.21 (0.15–0.30), with an assumed catch of 4,453 t. Natural mortality was estimated to be 0.49 (0.41–0.58) (ages 5–8) in 2019. Values during the last four years are the highest in the time series. Recruitment (age 2) estimates have been below the long-term average since the mid-1990’s. Projection of the stock to 2022 was conducted assuming fishery removals to be within +/-30% of current levels, assuming a catch of 4,453 t for 2019, and with no catch. Under these scenarios, there is a probability >99% that the stock will remain below B_lim between 2020 and the beginning of 2022. The probability of stock growth to 2022 from 2019 is less than 1% or less across catch scenarios (+/-30% of current levels) and is 16% 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 3Ps remain above normal, and the spring bloom continues to be reduced in magnitude. Zooplankton biomass in 3Ps was near normal in 2017 and 2018 after four years of low production, with an increased proportion of smaller species. Data were unavailable from 2019. Ongoing warming trends, together with an increased dominance of warm water fishes, indicate that this ecosystem continues to experience structural changes. Reduced growth and condition indicate that cod productivity in 3Ps is reduced.

Research Document 2024/002 (PDF, 8,204 KB)

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