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Science Response 2020/029

Information for identification of candidate critical habitat of Athabasca Rainbow Trout (Oncorhynchus mykiss)


Athabasca Rainbow Trout (Oncorhynchus mykiss) is a genetically distinct population of Rainbow Trout, found in tributary streams and the mainstem of the Athabasca River drainage of Western Alberta. Considered a "remnant population" from the last ice age, it is thought that the Athabasca Rainbow Trout has managed to survive in its unique coldwater habitat by maintaining a small body size into adulthood (Sawatzky 2018). However, Athabasca Rainbow Trout populations have declined by > 50% of their range (DFO 2018). The major threats to Athabasca Rainbow Trout are human-caused sedimentation of streams, stream fragmentation, non-native species (including genetic introgression and competition), and overfishing (Athabasca Rainbow Trout Cumulative Effects model, in prep). Climate change, cumulative effects of habitat loss/degradation, road development, and resource extraction also represent threats for Athabasca Rainbow Trout.

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has assessed Athabasca Rainbow Trout as Endangered. Fisheries and Oceans Canada (DFO) Species at Risk program has followed this decision and listed Athabasca Rainbow Trout as Endangered under the Species at Risk Act (SARA) in June 2019. Subsequently, a recovery strategy will be developed that must identify the species' Critical Habitat defined as "the habitat that is necessary for the survival or recovery of a listed species". Under the SARA S.41.1(c) a species' Critical Habitat must be identified to the greatest extent possible, based on the best available information.

DFO Species at Risk program has requested Science Advice in support of the identification of candidate Critical Habitat and residence for the Athabasca Rainbow Trout. This Science Response Report results from the Science Response Process of December 18, 2019 on the Information for Identification of Candidate Critical Habitat for Athabasca Rainbow Trout (Oncorhynchus mykiss).

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