Population Size Estimation of North Atlantic Right Whales From 1990-2024

This report serves to update the population size estimate of North Atlantic right whales (Eubalaena glacialis; hereafter, right whales) for the most recent year of available sightings data. Using an established capture-recapture framework (Pace et al., 2017) and a new calf-integration approach (Linden, 2025), the estimated median population size at the start of 2024 was 384 whales, with a 95% credible interval ranging from 375 to 394. The sharp decrease in the population size observed from 2015-2020 appears to have slowed, although the right whale population continues to experience annual mortalities above recovery thresholds. The updated right whale population estimate will be provided to the Atlantic Scientific Review Group for consideration in the 2026 Atlantic Stock Assessment Review process.