Southern Gulf of St. Lawrence (NAFO Division 4TVn) spring spawning Atlantic Herring (Clupea harengus) stock assessment to 2023

Abstract

Status The Spawning Stock Biomass (SSB) of southern Gulf of St. Lawrence (NAFO division 4TVn) spring spawning Atlantic Herring has been in the Critical Zone of the Precautionary Approach (PA) Framework since the early 2000s. As of 2022 and 2023, SSB of spring spawning Atlantic Herring has likely (> 95% probability) remained in the Critical Zone. Trends Since 2022, the estimated SSB of spring spawning Atlantic Herring has remained consistently low, with little to no sign of increasing biomass. Recruitment of spring spawning Atlantic Herring has remained relatively stable at low levels since 1993. Starting in 2010, natural mortality estimates for older ages of spring spawning Atlantic Herring sharply increased up to 2018, then slightly decreased and remained at high levels. Ecosystem and Climate Change Considerations Low recruitment of spring spawning Atlantic Herring associated with long-term environmental trends including water temperature increases and changes in prey dynamics is not expected to improve. Higher water temperature, poor food availability and high predator abundance likely have negative implications for Atlantic Herring size-at-age, fecundity and overall abundance. ock Advice Under current conditions of high natural mortality, declines in weight-at-age, and low recruitment, the probabilities that SSB of spring spawning Atlantic Herring will have a 5% increase by 2026 ranges from 58.6% at a catch of 0 tonnes (t) to 57.3% at a catch 500 t. Even in the absence of fishery removals, it is likely (> 84.7% probability) that the stock of spring spawning Atlantic Herring will remain in the Critical Zone by 2029. The probability of a 5% increase in SSB by 2029 is around 49% depending on the catch option. Other Management Questions Since 1998, fishing mortality of spring spawning Atlantic Herring exceeded the provisional harvest decision rule of the Precautionary Approach Framework. Since the closure of the commercial and bait fisheries in 2022, low levels of bycatch in fall fisheries and scientific surveys are the main sources of reported catch. Total bait removals and discards-at-sea of spring spawning Atlantic Herring are not included in this assessment.