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APPEIvDIX A-1 



University 

 of Montana 



Departmeni of Zoology • Missoula, Montana 59812 • (406)243-5122 



January 9, 1986 



Don Peters 



Montana Department of Fish, Wildlife and Parks 

 3201 Spurgin Road 

 Missoula, Montana 59801 



Don , 



We have completed the electrophoretic analysis of the samples of 

 Salmo you collected from the following locations: Gold Creek (col 

 8/29/85; N=26) , Martin Creek (9/ 23/ 85 ; 25) , Meadow Creek (8/22/85; 

 25), Moose Creek (9/4/85;25), Sleeping Child Creek (9/5/85;25), 

 and Tolan Creek (8/28/85 ; 26) in the Bitterroot River drainage and 

 Rattlesnake Creek (10/4/85;32) in the Clark Fork River drainage. 

 We detected only westslope cutthroat trout, S. clarki lewisi , 

 genetic material at those loci that can be used to distinguish 

 the rainbow, S. gairdneri , Yellowstone cutthroat, S.c. bouvieri , 

 and westslope cutthroat trout (Table 1) in all the samples from 

 the Bitterroot drainage. With the sample sizes from these 

 creeks, we are capable of detecting as little as one percent 

 rainbow trout genetic material in a population 95 percent of the 

 time and as little as one percent Yellowstone cutthroat trout 

 genetic material greater than 99 percent of the time. Thus, the 

 samples from these creeks almost certainly came from 'genetically 

 pure' populations of westslope cutthroat trout. 



The protein products of 45 loci were analyzed in all the fish 

 (Table 2) . The allele frequencies at those loci at which we 

 detected evidence of genetic variation in the samples of 

 westslope cutthroat trout are given in Table 3. Although the 

 Ck2(100) allele is characteristic of rainbow trout, we feel that 

 its presence in the Martin and and Moose Creek samples is more 

 likely indicative of westslope cutthroat trout intraspecif ic 

 genetic variation than of introgression with rainbow trout. For 

 example, if there actually is 4 percent rainbow trout genetic 

 material in the Martin Creek population (the frequency of the 

 Ck2 ( 100) allele) , then we expect not to detect alleles 

 characteristic of rainbow trout at the other 5 loci that 

 distinguish the rainbow and westslope cutthroat trout only one 

 out of 25,000 times. The same argument pertains to the presence 

 of the Idhl(-75) allele in the Sleeping Child Creek sample. 



The average percentage of heterozygous loci per individual and 

 the proportion of polymorphic loci in the samples from the 

 Bitterroot drainage (Table 3) cluster into the upper end of the 

 distribution of these parameters among 45 other populations of 



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