Otlier states have tried rearing golden trout under hatchery 

 conditions. Atteirpts to hold brood stocks at Mount Whitney Fish 

 Hatchery in California were abandoned, due to a high incidence of 

 furnunculosis and columnaris (Toth, pers. comm.). A brood stock 

 at VJyoming's Story Fish Hatchery had excessive mortality, due to 

 intestinal flukes (Mitchum and Moore 1969). Fish reared in slow- 

 growth, cold-water hatcheries have been less susceptible to harm- 

 ful infections. 



Genetics (Phelps 1982) 



The purpose of the genetic investigation was to determine 

 the amount and type of genetic variation that occurs in Montana 

 golden trout, identify any evidence of introgression from other 

 Salmo species, and determine if the observed morphological 

 differences had a genetic basis. Findings concluded that golden 

 trout in Montana had less genetic variation than other Salmo 

 species and golden trout populations from California. No 

 evidence of introgression from other Salmo was detected in any of 

 the nine golden trout populations. There was a statistically 

 significant gene frequency difference between golden trout popu- 

 lations started from sources in Montana and the Surprise Lake, 

 Wyoming source at the only variable locus in these fish. 



Tlie amount of genetic variation found in these golden trout 

 populations in Montana held a low average heterozygosity of 

 0.005. The variation was about one-third of that found in Cali- 

 fornia's golden trout populations. Golden trout stocks from 

 Cottonwood lakes has less genetic variation than the original 

 golden trout stocks in California (Kornblatt 1973; Smith 1981). 

 Very few adults were probably used to start the original popula- 

 tion in the Cottonwood Lake system.. However, the amount of 

 genetic variation varied substantially between the different 

 Cottonwood lakes, and gene frequencies of variable loci may have 

 greatly changed since the golden trout were brought to Montana. 

 Genetic variation apparently has been lost since golden trout 

 were brought to Montana. Genetic variation present at Idh-3,4 in 

 all the Cottonwood Lake samples did not occur in any of the 

 golden trout samples from Montana. 



There was no indication of hybridization with other Salmo 

 species. No alleles characteristic of Yellowstone cutthroat 

 trout (Salmo clarki bouveri) or westslope cutthroat trout SallTiQ 

 clarki lewisi) were observed in the samples. There were no 

 electrophoretically detectable alleles present in golden trout 

 that distinguished them from rainbow trout. This also had been 

 found in other studies (Allendorf and Utter 1979; Gall et al. 

 1976; Gold 1981; Kornblatt 1973; Smith 1981). Even though there 

 were no diagnostic loci betv;een golden and rainbow trout, the 

 type and amount of genetic variation present was an indication of 

 v/hether there had been any past rainbow trout introgression. 



Genetic variation found in golden trout in Montana was one- 

 tenth of that commonly found in rciinbow trout populations. Many 



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