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Thinking Forward to Long Term Recovery of Critical Bull Trout Habitat in the North Saskatchewan River


Thinking Forward to Long Term Recovery of Critical Bull Trout Habitat in the North Saskatchewan River

The North Saskatchewan River (Banff National Park) is a heritage river that begins at the foot of the Saskatchewan Glacier and flows south through the northern tip of Banff National Park. Bull trout were once widespread and abundant top predators across their range in western and northern Canada, but they are now in decline. Threats to bull trout include aquatic invasive species like whirling disease and non-native species historically introduced by Parks Canada. In 2019 the Saskatchewan-Nelsons River bull trout population was listed as threatened under Canada’s Species at Risk Act.

Bull trout. Photo: Parks Canada

When a species becomes listed as threatened it requires a federal recovery strategy to be developed within two years. An important part of the recovery strategy is to identify areas of critical habitat. Critical habitat is habitat that is required for the recovery or survival of a listed species. Significant parts of the North Saskatchewan River are now officially designated as critical habitat for bull trout based on features such as water depth, temperature and flow. These features are all essential to sustaining bull trout populations at different life stages. The bull trout recovery strategy includes a 30 M riparian buffer which is 30 M of shore from the high-water mark. This inclusion recognizes the importance that the shore plays in bull trout habitat. It prevents sediment and pollution from entering the waterway, provides shading and food sources and is important for protecting undercut bank habitat and bank stability.

The North Saskatchewan River (Banff National Park) is also home to a number of bull trout life histories. The fluvial and adfluvial histories are migratory so it is important to maintain large areas of cool, clean and connected waters for this species. We know from telemetry work that many bull trout migrate back into the park to access important and rare spawning locations. These spawning locations are in small tributaries to the North Saskatchewan River and contain key ground water inputs that prevent bull trout eggs from freezing over the winter.

North Saskatchewan River in Banff National Park. Photo: Parks Canada

In Banff National Park we are carefully monitoring and managing activities near or adjacent to riparian areas like construction, highway and road improvements, or forest management projects (e.g. wildfire risk reduction and wildlife habitat enhancements) as well as threats such as sediment releases and water withdrawals. But, even with greater habitat protection, this species cannot recover from historical fisheries and management practices on its own. Over the next decade Parks Canada will begin restoration projects to improve the long term recovery for the bull trout that ply the waters of this Canadian Heritage River.

Underwater bull trout. Photo: Parks Canada