Freshwater migration and behaviour of wild adult Atlantic Salmon (Salmo salar) in the Miramichi River, New Brunswick, Canada
University of New Brunswick
Historically, the Miramichi River, New Brunswick, Canada, had the largest population of Atlantic Salmon (Salmo salar) in North America but has now failed to consistently meet conservation targets set by Fisheries and Oceans Canada for over two decades. Miramichi River salmon return as mature adults to their natal river in either an early (June/early July) or late (September/October) run group, where they enter the river and migrate upstream to spawning areas. The specific, in-river migratory behaviour of the two temporally distinct runs and the habitats utilized during migration are poorly understood in the Miramichi River. In this thesis, radio telemetry was used to monitor adult migration behaviour and habitat selection for early and late run salmon in the Miramichi River. On average, early run salmon migrated 1.5 river km per day (rkm/d), and selected deep habitat (>0.5 m) with large substrate sizes. Salmon started to use thermal refugia when river temperatures reached 19 °C, and increasingly at temperatures > 22 °C. In autumn, river conditions appeared to delay late run salmon from entering freshwater for weeks. Late run salmon migrated between 1.0 – 2.4 rkm/d on average, selected deep habitat types (>0.5 m) with cobble substrate, spawned between mid-October to late November, and began migrating downstream after spawning. Fisheries managers can use this information for better conservation, restoration and rehabilitation of Miramichi Atlantic Salmon population and their critical habitat.