Science Response 2020/044

Information for Identification of Candidate Critical Habitat of Bull Trout, Salvelinus confluentus (Saskatchewan-Nelson Rivers Populations)

Context

Bull Trout, (Salvelinus confluentus), is a char endemic to western North America. They occur in cold, clean, complex, and connected watercourses and are sensitive to habitat alterations due to their specific habitat requirements (COSEWIC 2012). They are divided into five Designatable Units (DU) determined by their National Freshwater Biogeographic Zone classification, range disjunction, and genetic lineage. The distribution range of Bull Trout has decreased over the last century, resulting in fragmented and isolated populations. Declines in population abundance have been observed across the range, particularly in the USA and the eastern range in Alberta (DFO 2017). Major threats to Bull Trout are habitat alteration, habitat fragmentation or loss, non-native species, and overfishing. Additionally, climate change, cumulative effects of habitat loss/degradation, road development, and resource extraction also represent threats to Bull Trout (DFO 2017).

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has assessed Bull Trout (Saskatchewan-Nelson rivers populations), DU 4 as Threatened (COSEWIC 2012). In August 2019, the Government of Canada listed Bull Trout (Saskatchewan-Nelson rivers populations) as Threatened under the Species at Risk Act (SARA). Subsequently, a Recovery Strategy must be developed that identifies the species’ Critical Habitat, or “the habitat that is necessary for the survival or recovery of a listed species and that is identified as the species Critical Habitat in the Recovery Strategy for the 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 to support the identification of candidate Critical Habitat for Bull Trout. This Science Response Report results from the Science Response Process of February 27, 2020 on Information for Identification of Candidate Critical Habitat of Bull Trout, Salvelinus confluentus (Saskatchewan-Nelson rivers populations).

Science Response 2020/044 (PDF, 11,977 KB)

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