An analysis of spatial and environmental factors influencing hybridization between native westslope cutthroat trout (Oncorhynchus clarki lewisi) and introduced rainbow trout (O. mykiss) in the upper Kootenay River drainage, British Columbia

2005 ◽  
Vol 6 (3) ◽  
pp. 369-384 ◽  
Author(s):  
E. M. Rubidge ◽  
E.B. Taylor
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Environmental Factors ◽  
Cutthroat Trout ◽  
Oncorhynchus Clarki ◽  
Westslope Cutthroat Trout ◽  
River Drainage ◽  
Factors Influencing ◽  
Oncorhynchus Clarki Lewisi

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.

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