WCT Multi-state Assessment February 1 0. 2003 



number of stream segments occupied. Number of stream segments was not a meaningful 

 measure because this number does not equate to number of populations and lengths of stream 

 segments varied widely. Where field data were available abundance was rated based on how 

 similar the measured abundance was to measured abundances from areas of similar types of 

 habitat that were not impacted by human activities. Where no field data were available, 

 abundance classes were subjective and based, to a large extent, on the quality of the habitats 

 occupied. Consequently, analyses between the relative abundance levels we assigned and land- 

 use or other habitat-related variables were not independent. 



Table 2. Codes and descriptions used for 

 assessing relative abundance of 

 westslope cutthroat trout in 2002. 



Code Description 



99 Unknown 



A At or near site potential 



C Slightly below site potential 



R Significantly below site potential 



Designated "Conservation Populations" 



WCT are considered a game fish by all state and federal agencies that manage this subspecies. 

 Consequently, all WCT populations have sport fish value and are managed as such by the 

 various states and national parks in which they occur, regardless of their genetic status. Many 

 populations of WCT are managed as "conservation populations" with additional management 

 emphasis placed on preserving these populations. Most of the western states within the U.S. that 

 support cutthroat trout developed a position paper on genetic management (Anon 2000). This 

 position paper describes a hierarchical classification scheme for conserving cutthroat trout that 

 includes: 1) a core made up of genetically unaltered populations or individuals; 2) designated 

 conservation populations that may be either genetically unaltered or slightly introgressed; and 3) 

 populations that are managed primarily for their recreational fishery value. Core populations are 

 recognized as having important genetic value and would serve as donor sources for developing 

 either captive brood or for re-founding additional populations. Management will emphasize 

 conservation, including potential expansion, of both core and conservation populations, but 

 conservation populations will likely not be used to re-found additional populaUons unless they 

 have been tested as non-introgressed. 



For this assessment any stream segment that supported WCT could potentially be designated as 

 either an individual "conservation population", or aggregated as part of a larger "conservation 

 population". Adjacent stream segments that supported WCT, and were connected, were 

 aggregated into a single conservation population, especially if evidence existed that WCT moved 

 between stream segments. Designated "conservation populations" that occupied two or more 

 connected stream segments may function as "metapopulations" (Hanski and Gilpin 1991). 

 Populations were designated as "conservation populations" based on how they fit into categories 

 (Table 3) using the following attributes: genetic status, expression of unique or multiple life- 



Page - 8 



