Genetic Identification of Native Cutthroat Trout (Oncorhynchus clarki) and Introgressive Hybridization with Introduced Rainbow Trout (O. mykiss) in Streams Associated with the Alvord Basin, Oregon and Nevada

Copeia ◽  
1991 ◽  
Vol 1991 (3) ◽  
pp. 854 ◽  
Author(s):  
Devin M. Bartley ◽  
Graham A. E. Gall
Keyword(s):  
Rainbow Trout ◽  
Introgressive Hybridization ◽  
Cutthroat Trout ◽  
Genetic Identification ◽  
Oncorhynchus Clarki ◽  
Alvord Basin

Spread of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, Oncorhynchus mykiss

2003 ◽  
Vol 60 (12) ◽  
pp. 1440-1451 ◽  
Author(s):  
Nathaniel P Hitt ◽  
Christopher A Frissell ◽  
Clint C Muhlfeld ◽  
Fred W Allendorf
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Environmental Variability ◽  
Environmental Gradients ◽  
Cutthroat Trout ◽  
Oncorhynchus Clarki ◽  
Spatial And Temporal Patterns ◽  
Westslope Cutthroat Trout ◽  
Oncorhynchus Clarki Lewisi ◽  
Flathead River

We examined spatial and temporal patterns of hybridization between native westslope cutthroat trout, Oncorhynchus clarki lewisi, and nonnative rainbow trout, O. mykiss, in streams of the Flathead River system in Montana, U.S.A. We detected hybridization in 24 of 42 sites sampled from 1998 to 2001. We found new Oncorhynchus mykiss introgression in seven of 11 sample populations that were determined to be nonhybridized in 1984. Patterns of spatial autocorrelation and linkage disequilibrium indicated that hybridization is spreading among sites and is advancing primarily via post-F1 hybrids. Although hybridized populations were distributed widely throughout the study area, the genetic contribution from O. mykiss decreased with increasing upstream distance from the Flathead River mainstem, suggesting that O. mykiss introgression is spreading in an upstream direction. The spread of hybridization may be constrained more by demographic than by environmental factors, given that (i) hybridized populations generally encompassed the range of environmental variability in nonhybridized populations, and (ii) hybridization status was more strongly associated with neighborhood statistics than measured environmental gradients.

Introgressive Hybridization in Populations of Paiute Cutthroat Trout (Salmo clarki seleniris)

1981 ◽  
Vol 38 (8) ◽  
pp. 939-951 ◽  
Author(s):  
Craig A. Busack ◽  
G. A. E. Gall
Keyword(s):  
Population Structure ◽  
Rainbow Trout ◽  
Introgressive Hybridization ◽  
Cutthroat Trout ◽  
The Other ◽  
Salmo Gairdneri ◽  
Electrophoretic Data ◽  
The Difference ◽  
Salmo Clarki ◽  
Two Populations

Two populations of Paiute cutthroat trout (Salmo clarki seleniris) were compared meristically and electrophoretically with Lahontan cutthroat (S. c. henshawi) and rainbow trout (S. gairdneri) to elucidate population structure and verify the occurrence of introgressive hybridization. In Silver King Creek, both meristic and electrophoretic evidence indicated two populations were present, one appearing to be pure Paiute cutthroat, the other Paiute cutthroat introgressed with rainbow trout. Lahontan cutthroat introgression was a possibility in Silver King Creek but could not be evaluated because of the strong meristic and electrophoretic similarity of Paiute and Lahontan cutthroat. The other Paiute population, Cottonwood Creek, meristically appeared to be pure Paiute cutthroat but electrophoretic data indicated it was introgressed with rainbow trout. The existence of the two Silver King Creek populations indicated introgression was incomplete in that stream; introgression appeared to be complete in Cottonwood Creek. The meristic similarity of Cottonwood Creek trout to pure Paiute cutthroat was probably a result of strong selection by management agencies for a Paiute cutthroat phenotype. Electrophoresis was more discriminating than meristic analysis in this study in detecting introgression. Electrophoresis also allowed more detailed analysis of population structure than meristics because of the difference in complexity of the genetic systems analyzed by the two techniques. However, the application of both techniques contributed greatly to our understanding of introgression in the Paiute cutthroat and demonstrated the complementarity of the two approaches.Key words: Salmo clarki, Salmo gairdneri, Paiute cutthroat, Lahontan cutthroat, meristics, electrophoresis, introgression, hybridization, gametic disequilibrium, principal components

Genetic Identification of Cutthroat Trout, Salmo clarki, in Glacier National Park, Montana

1987 ◽  
Vol 44 (11) ◽  
pp. 1830-1839 ◽  
Author(s):  
Leo F. Marnell ◽  
Robert J., Behnke ◽  
Fred W. Allendorf
Keyword(s):  
National Park ◽  
Introgressive Hybridization ◽  
Cutthroat Trout ◽  
Genetic Identification ◽  
Glacier National Park ◽  
The North ◽  
Continental Divide ◽  
Headwater Lakes ◽  
Yellowstone Cutthroat Trout ◽  
Salmo Clarki

Trout populations in 29 lakes in Glacier National Park were identified by meristic and electrophoretic analyses to assess the extent of introgressive hybridization between introduced nonnative trout and the indigenous cutthroat trout, Salmo clarki lewisi. Native cutthroat trout remain in 16 lakes draining to the North and Middle forks of the Flathead River; no native trout were found east of the Continental Divide. Introduced Yellowstone cutthroat trout, Salmo clarki bouvieri, occur in six headwater lakes. Hybrid populations, including both S. c. lewisi × bouvieri and S. clarki × S. gairdneri, inhabit six lakes. Hybridization between native and introduced trouts has been minimal, apparently due to strong selective pressures favoring the indigenous genotype. Close agreement was observed between the meristic and electrophoretic results.

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