Northern Contingent Atlantic Mackerel (Scomber scombrus) Stock Assessment in 2024

Abstract

Status The 2023 and 2024 SSB were estimated at 32% and 35% of the LRP, placing the stock in the Critical Zone of the precautionary approach (PA) with a high probability (greater than 95%). The 2023-2024 fishing mortalities were below the RR with moderate to high probability (58 and 83%), respectively. Trends The stock has been near or below the LRP since 2011. Recent average recruitment (2011–2024) was at 26% of levels estimated before the stock fell below the LRP (1969–2010). There have been no signs of a notable recruitment event since 2015. Fish older than 6 years have been uncommon in the stock since the early 2010s. Ecosystem and Climate Change Considerations Uncertainty associated with environmental effects on mackerel recruitment is implicitly accounted for in the assessment model. Stock Advice The probability of the SSB growing out of the Critical Zone by 2027 ranges from 30% under a TAC of 0 t to 13% under a TAC of 8,000 t. Both scenarios assume continued unaccounted-for Canadian recreational and U.S. landings. Under the same scenarios, the probability that the SSB in 2027 will be greater than in 2025 ranges from 81% under a TAC of 0 t to 27% under a TAC of 8,000 t. There is a high probability (greater than 75%) that the SSB in 2027 would be greater than in 2025 with a TAC not exceeding 500 t. In the absence of all fishing (F=0), the stock is expected to grow out of the Critical Zone between 2031 and 2033. This timeline increases to 2032 and 2035 when annual removals by the U.S. fisheries are included. Other Management Questions The L50 of all cohorts from 2014 onwards (average = 260 mm) has been below the current minimum legal size of 268 mm. This decrease is not outside the scope of historical fluctuations. There is currently no evidence that fishing on spawning grounds during the spawning period is more selective, more efficient or causes habitat or spawning disturbances that could negatively affect the stock rebuilding potential.