Yellowstone cutthroat trout, or both. Unless future data indicate otherwise, however, the conservative approach would 

 be to consider this a non-hybridized westslope cutthroat trout population. 



Canyon Lake 3095 



PINE fragments characteristic of only westslope cutthroat trout were detected in the sample. With a sample size of 

 1 7 individuals, we have an 87% chance of detecting as little as a one percent rainbow trout genetic contribution and a 

 74% chance of detecting as little as a one percent Yellowstone cutthroat trout genetic contribution to a hybrid swarm. 

 Thus, we cannot reasonably exclude the possibility that this population may be slightly hybridized with rainbow trout, 

 Yellowstone cutthroat trout, or both. Unless future data indicate otherwise, however, the conservative approach would 

 be to consider this a non-hybridized westslope cutthroat trout population. 



Patrick Creek 3096 



Sample 1 



A PINE fragment usually characteristic of rainbow trout was detected at only one of si.x diagnostic loci for this 

 species that were analyzed in the sample. The fragment was detected in only one individual. Thus, its presence could 

 indicate a small amount of hybridization with rainbow trout or it could simply be westslope cutthroat trout PINE 

 genetic variation that is electrophoretically indistinguishable from that usually characteristic of rainbow trout. 

 Presently, we cannot distinguish between these possibilities. This will require analyzing additional fish or diagnostic 

 loci. Thus, at this time the status of this population is uncertain, but conservatively it should be considered to be non- 

 hybridized westslope cutthroat trout unless additional information indicates otherwise. 



Sample 2 . 



A PINE fragment usually characteristic of rainbow trout was detected at only one of si.\ diagnostic loci for this 

 species that were analyzed in the sample. This fragment, detected at a different locus than the 'rainbow' fragment 

 detected in Sample 1, was present in six of the 1 1 fish in the sample. Thus, its presence could indicate hybridization 

 with rainbow trout or it could simply be westslope cutthroat trout PINE genetic variation that is electrophoretically 

 indistinguishable from that usually characteristic of rainbow trout. In this situation, we favor the latter interpretation 

 because if its presence was due to hybridization it is highly unlikely (contingency table chi-square; P<0.001) that we 

 would not detect evidence of hybridization with rainbow trout at the other five diagnostic loci for this fish that were 

 analyzed. At this time, therefore, this population conservatively should be considered to be non-hybridized westslope 

 cutthroat trout. 



Webb Lake 3097 



PINE fragments characteristic of rainbow trout were detected in this sample at two of the six diagnostic loci analyzed 

 that are usually characteristic of this species. The rainbow trout fragments were detected in only one of the five fish in 

 the sample. The other four fish possessed PINE fragments characteristic of only westslope cutthroat trout. Thus, this 

 sample appears to have contained a mixture of non-hybridized westslope cutthroat trout and late generation hybrids 

 between westslope cutthroat and rainbow trout. The small sample size, however, precludes making the conclusion the 

 sample contained non-hybridized westslope cutthroat trout with much conviction because we cannot reasonably 

 determine whether or not the rainbow trout fragments are randomly distributed among the fish in the population 

 because of greatly reduced statistical power. Regardless of whether or not the population does contain non-hybridized 

 westslope cutthroat trout, from a practical perspective it should simply be considered to be hybridized. The presence 

 of late generation hybrids makes reliably distinguishing non-hybridized westslope cutthroat trout from hybrid 

 individuals problematic because many of the latter by chance will have just westslope cutthroat trout fragments at the 

 few diagnostic loci that we usually analyze. 



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