Stock assessment of NAFO subdivision 3Ps cod

Abstract

This stock is assessed using an integrated state-space model, which incorporates landings and catch-at-age (1959–2020), time-varying natural mortality informed by trends in cod condition, and includes abundance indices from research surveys using bottom trawls conducted by Canada (1983–2021), France (1978–91), industry (Groundfish Enterprise Allocation Council [GEAC],1998–2005), and standardized catch rate indices from inshore Sentinel gillnet and line-trawl surveys (1995–2020). Spawning Stock Biomass (SSB) in 2022 is projected to be 31.5 kt (95% CI: 25.3–49.5 kt). SSB remains in the critical zone, at 48% (95% CI: 38–60%) of the Limit Reference Point (LRP) as defined by the DFO Precautionary Approach (PA) Framework. The stock and fishery are dominated by a single cohort (2011), which accounted for 29% of the SSB in 2021 and 45% of the commercial catch in 2020. Recruitment since the 2011 cohort has remained among the lowest in the time series. Natural mortality (M) is currently driving the dynamics of this stock. M has increased from the early 2000s and is estimated at 0.34 (ages 5–8) in 2021. Fishing mortality has been declining since 2000 and in 2021 is estimated to be 0.03, the lowest level since the moratorium (1994 to 1996). Ongoing warming trends, together with more recent increased dominance of warm water fishes, indicate that this ecosystem continues to experience structural changes. In this context, bottom-up effects are contributing to poor fish condition and high natural mortality of cod. Projection of the stock to 2024 was conducted assuming fishery removals ranging from 0 to 2.3 times an assumed catch of 1,346 t for 2021. Under these scenarios, there is a probability >99% that the stock will remain below the LRP between 2022 and the beginning of 2024. Stock growth is projected over the short term (to 2024) at probabilities of 50% and 75% with removals of 3,100 t and 1,600 t, respectively. However at the upper range of these catches stock decline in 2023 should be expected. When there are no removals in this period, the probability of stock growth is 93%. 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.