Athabasca rainbow trout

The Athabasca rainbow trout was considered as a form of the Columbia River redband trout (O. mykiss gairdneri) subspecies in the trout handbook of Robert J. Behnke (1992), but considered a separate, yet unnamed subspecies by L. M. Carl of the Ontario Ministry of Resources in work published in 1994.^[1]

They are not considered a distinct subspecies from other rainbow trout.^[2]

The Athabasca rainbow trout is primarily found in the cold headwaters of the Athabasca drainage in Alberta, Canada.^[1][2] The Athabasca rainbow trout is one of the few native rainbow trout populations found in an Arctic Ocean watershed.^[3] The Athabasca River is a tributary of the Mackenzie River system which flows north into the Arctic Ocean.^[3]

In the winter they will use the largest and deepest pools in any occupied stream as an overwintering spot.^[2]

The Athabasca rainbow trout spawn in the springtime in streams with fine gravels that are free of silts in clays, and that also have moderate flow rates.^[2] They spawn later in the spring than other rainbow trout.^[2]

The Athabasca rainbow trout used to be considered a "May be at risk" species^[4] in Alberta due to potential habitat loss and hybridization with introduced rainbow trout".^[1] As of August 2019 it is designated under the Species At Risk Act (SARA) as Endangered.^[2] Their main threats are invasive species and the increased competition they bring, introgression with non-native rainbow trout introduced as game fish, fishing pressures, habitat loss and fragmentation, sedimentation, climate change, and water pollution.^[2]