Westslope cutthroat trout COSEWIC assessment and status report: chapter 1

Assessment Summary

 

Assessment Summary – November 2006

Common name: Westslope cutthroat trout

Scientific name: Oncorhynchus Clarkii Lewisi

Status: Special Concern

Reason for designation: Populations are stressed by hybridization and competition with introduced species. Furthermore, expanding urban development, agricultural activities and resource-based industries are expected to lead to additional stresses associated with habitat loss and degradation, as well as increased exploitation. It should be noted that this assessment includes only genetically pure, native populations of the species occurring within their historical range. Any populations known to be hybridized significantly (i.e. >1%) with other trout species, or to have been introduced into a system previously free of native populations, were not assessed.

Occurrence: British Columbia

Status history: Designated Special Concern in May 2005. Status re-examined and confirmed in November 2006. Assessment based on a new status report.

 

Assessment Summary – November 2006

Common name: Westslope cutthroat trout

Scientific name: Oncorhynchus Clarkii Lewisi

Status: Threatened

Reason for designation: Native populations have been reduced by almost 80% through over-exploitation, habitat degradation, and hybridization / competition with introduced, non-native trout. Remaining, genetically pure, individuals persist as mainly severely fragmented, remnant headwater populations. It should be noted that this assessment includes only genetically pure, native populations of the species occurring within their historical range. Any populations known either to be hybridized significantly (i.e. >1%) with other trout species, or to have been introduced into a system previously free of native populations, were not assessed.

Occurrence: Alberta

Status history: Designated Threatened in May 2005 and in November 2006. Assessment based on a new status report.

 

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