Westslope cutthroat trout COSEWIC assessment and status report: chapter 9

Special Significance of the Species

Cutthroat trout are a unique and important component of Canada’s freshwater fish fauna. As one of the first salmonids to recolonize western Canada in the wake of retreating glaciers, they are often the only native trout throughout much of their Canadian range. As such, they likely play an important role in structuring many north temperate aquatic ecosystems (McPhail and Carveth 1992). Their small size at maturity allows them to penetrate smaller streams than most other salmonids, where they may make significant contributions to the growth of riparian vegetation and forests in terms of nutrient recovery (sensu Willson and Halupka 1995). Furthermore, their strict habitat requirements make cutthroat trout an indicator species for the general health of many ecosystems; they have often been referred to as “the canary in a coal mine”. Canadian populations inhabit a variety of extreme habitats (in terms of elevation, temperature, and other physiogeographic factors). Populations of WCT in British Columbia and Alberta, for example, exist on the northern periphery of the subspecies’ original range and likely contain a number of unique specializations for colder, less productive ecosystems typical of the area. Adaptations to marginal habitat might be necessary for reintroduction to extirpated areas and, as such, constitute an important component of species biodiversity.  Westslope cutthroat trout are of traditional importance to several First Nations groups and are a popular sport fish in western Canada (second perhaps only to rainbow trout/steelhead in terms of angler interest). Sportfishing revenues from recreational fisheries provide a substantial contribution to many local economies. While historically a widespread species, WCT have shown dramatic global declines in the number and distribution of populations so that the core distribution of both populations now occurs in Canada. The maintenance of quality populations here in Canada may be required for attempts to re-establish populations that have been extirpated, and the future preservation of the species as a whole.

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