2026/04/28 by Jessie Lilly, Chantelle Burke, Christiane Dufresne +33
Environmental Science · #Fish Ecology and Management Studies #Marine and fisheries research #Isotope Analysis in Ecology
paper · doi:10.1139/cjfas-2025-0197
Atlantic salmon (Salmo salar) populations are at historic lows, primarily due to poor marine survival, and knowledge gaps regarding their migration limit our ability to identify population-specific stressors. From 2021–2023, 3900 smolts were tagged and tracked from 32 rivers across eastern Canada to the Labrador Sea. Migration routes were generally uniform within most populations, but distinct secondary routes in others suggest adaptive flexibility and shared environmental cues across a broad spatial scale. Despite a strong latitudinal gradient in the initial timing of migration, with southern populations leaving earlier, temporal overlap increased at northern marine locations. This convergence coincided with the seasonal warming of shelf waters above 4 °C and a narrow 4–10 °C thermal niche. This overview of early post-smolt migration highlights the journey’s active nature, the significance of estuarine stopover sites, and thermal limitations dictating the arrival in the Labrador Sea. Protecting this culturally and economically significant species will require population-specific management that accounts for cumulative stressors along these routes.