A molecular analysis of hybridization between native westslope cutthroat trout and introduced rainbow trout in southeastern British Columbia, Canada

2001 ◽  
Vol 59 (sa) ◽  
pp. 42-54 ◽  
Author(s):  
E. Rubidge ◽  
P. Corbett ◽  
E. B. Taylor
Keyword(s):  
British Columbia ◽  
Rainbow Trout ◽  
Molecular Analysis ◽  
Cutthroat Trout ◽  
Westslope Cutthroat Trout

Spatial and temporal spawning dynamics of native westslope cutthroat trout, Oncorhynchus clarkii lewisi, introduced rainbow trout, Oncorhynchus mykiss, and their hybrids

2009 ◽  
Vol 66 (7) ◽  
pp. 1153-1168 ◽  
Author(s):  
Clint C. Muhlfeld ◽  
Thomas E. McMahon ◽  
Durae Belcer ◽  
Jeffrey L. Kershner
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Cutthroat Trout ◽  
River System ◽  
Westslope Cutthroat Trout ◽  
Time And Space ◽  
Long Distance ◽  
Oncorhynchus Clarkii ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Spring Runoff

We used radiotelemetry to assess spatial and temporal spawning distributions of native westslope cutthroat trout ( Oncorhynchus clarkii lewisi ; WCT), introduced rainbow trout ( Oncorhynchus mykiss ; RBT), and their hybrids in the upper Flathead River system, Montana (USA) and British Columbia (Canada), from 2000 to 2007. Radio-tagged trout (N = 125) moved upriver towards spawning sites as flows increased during spring runoff and spawned in 29 tributaries. WCT migrated greater distances and spawned in headwater streams during peak flows and as flows declined, whereas RBT and RBT hybrids (backcrosses to RBT) spawned earlier during increasing flows and lower in the system. WCT hybrids (backcrosses to WCT) spawned intermediately in time and space to WCT and RBT and RBT hybrids. Both hybrid groups and RBT, however, spawned over time periods that produced temporal overlap with spawning WCT in most years. Our data indicate that hybridization is spreading via long-distance movements of individuals with high amounts of RBT admixture into WCT streams and stepping-stone invasion at small scales by later generation backcrosses. This study provides evidence that hybridization increases the likelihood of reproductive overlap in time and space, promoting extinction by introgression, and that the spread of hybridization is likely to continue if hybrid source populations are not reduced or eliminated.

Cold tolerance performance of westslope cutthroat trout (Oncorhynchus clarkii lewisi) and rainbow trout (Oncorhynchus mykiss) and its potential role in influencing interspecific hybridization

2014 ◽  
Vol 92 (9) ◽  
pp. 777-784 ◽  
Author(s):  
M.M. Yau ◽  
E.B. Taylor
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Water Temperature ◽  
Cold Water ◽  
Cutthroat Trout ◽  
Acclimation Temperature ◽  
Westslope Cutthroat Trout ◽  
Oncorhynchus Clarkii ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Differential Adaptation

Hybridization between rainbow trout (Oncorhynchus mykiss (Walbaum, 1792)) and westslope cutthroat trout (Oncorhynchus clarkii lewisi (Girard, 1856)) occurs commonly when rainbow trout are introduced into the range of westslope cutthroat trout. Typically, hybridization is most common in warmer, lower elevation habitats, but much less common in colder, higher elevation habitats. We assessed the tolerance to cold water temperature (i.e., critical thermal minimum, CTMin) in juvenile rainbow trout and westslope cutthroat trout to test the hypothesis that westslope cutthroat trout better tolerate low water temperature, which may explain the lower prevalence of rainbow trout and interspecific hybrids in higher elevation, cold-water habitats (i.e., the “elevation refuge hypothesis”). All fish had significantly lower CTMin values (i.e., were better able to tolerate low temperatures) when they were acclimated to 15 °C (mean CTMin = 1.37 °C) versus 18 °C (mean CTMin = 1.91 °C; p < 0.001). Westslope cutthroat trout tended to have lower CTMin than rainbow trout from two populations, second–generation (F2) hybrids between two rainbow trout populations, and backcrossed rainbow trout at 15 °C (cross type × acclimation temperature interaction; p = 0.018). Differential adaptation to cold water temperatures may play a role in influencing the spatial distribution of hybridization between sympatric species of trout.

scholarly journals Vive la résistance: genome-wide selection against introduced alleles in invasive hybrid zones

2016 ◽  
Vol 283 (1843) ◽  
pp. 20161380 ◽  
Author(s):  
Ryan P. Kovach ◽  
Brian K. Hand ◽  
Paul A. Hohenlohe ◽  
Ted F. Cosart ◽  
Matthew C. Boyer ◽  
...  
Keyword(s):  
Invasive Species ◽  
Rainbow Trout ◽  
Natural Populations ◽  
Cutthroat Trout ◽  
Field Studies ◽  
Selective Advantage ◽  
Hybrid Zones ◽  
Introduced Fish ◽  
Westslope Cutthroat Trout ◽  
Genome Wide

Evolutionary and ecological consequences of hybridization between native and invasive species are notoriously complicated because patterns of selection acting on non-native alleles can vary throughout the genome and across environments. Rapid advances in genomics now make it feasible to assess locus-specific and genome-wide patterns of natural selection acting on invasive introgression within and among natural populations occupying diverse environments. We quantified genome-wide patterns of admixture across multiple independent hybrid zones of native westslope cutthroat trout and invasive rainbow trout, the world's most widely introduced fish, by genotyping 339 individuals from 21 populations using 9380 species-diagnostic loci. A significantly greater proportion of the genome appeared to be under selection favouring native cutthroat trout (rather than rainbow trout), and this pattern was pervasive across the genome (detected on most chromosomes). Furthermore, selection against invasive alleles was consistent across populations and environments, even in those where rainbow trout were predicted to have a selective advantage (warm environments). These data corroborate field studies showing that hybrids between these species have lower fitness than the native taxa, and show that these fitness differences are due to selection favouring many native genes distributed widely throughout the genome.

Propagated Fish in Resource Management

2004 ◽  
Keyword(s):  
Rainbow Trout ◽  
Low Frequency ◽  
Cutthroat Trout ◽  
Natural Hybridization ◽  
Westslope Cutthroat Trout ◽  
Sympatric Populations ◽  
Oncorhynchus Clarkii ◽  
Mitochondrial Haplotypes ◽  
Directional Preference ◽  
Time Of Year

<em>Abstract.</em>—Westslope cutthroat trout <em>Oncorhynchus clarkii lewisi </em>are currently under a second review for listing as a threatened species under the Endangered Species Act. Both natural and anthropogenically induced hybridization has been previously documented between this subspecies and rainbow trout <em>O. mykiss </em>and between steelhead (anadromous rainbow trout) and coastal cutthroat trout <em>O. clarkii clarkii</em>. However, levels of reported introgression have varied greatly. To assess natural hybridization and the extent to which it may affect the frequency and persistence of <em>O. mykiss </em>alleles among sympatric populations of westslope trout, we used three nuclear loci to detect hybrids, and mitochondrial DNA to assess the direction of hybridization and introgression in Big Creek, Idaho and its tributaries. Natural hybridization between westslope cutthroat and sympatric rainbow trout/steelhead appears to occur at a relatively low frequency with numerous parental types still present in varying numbers within the drainage. Subsequent genetic analyses revealed no hybridization in samples from 2001 and percentages of hybrid genotypes within sample locations ranging from 1.6% to 13.3% in 2002. Differences between years may be attributable to sampling, time of year, and seasonal movements of westslope cutthroat trout and their hybrids. Furthermore, hybrids were more frequently observed (<em>p </em>< 0.01) with mitochondrial haplotypes of westslope cutthroat trout indicating a directional preference of westslope cutthroat females spawning with <em>O. mykiss </em>males.

scholarly journals Carbon dioxide-induced mortality of four species of North American fishes

2020 ◽  
Author(s):  
Hilary B. Treanor ◽  
Andrew Ray ◽  
Jon Amberg ◽  
Mark Gaikowski ◽  
Jason Ilgen ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Rainbow Trout ◽  
Common Carp ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Cutthroat Trout ◽  
Management Tool ◽  
Published Data ◽  
Westslope Cutthroat Trout ◽  
Minimum Concentration

There is growing interest in the use of carbon dioxide (CO 2 ) as a management tool for controlling invasive fishes.  However, there is limited published data on susceptibility of many commonly encountered species to elevated CO 2 concentrations.  Our objective was to estimate the 24-h LC 50 and LC 95 of four fishes (Rainbow Trout Oncorhynchus mykiss , Common Carp Cyprinus carpio , Channel Catfish Ictalurus punctatus , and Westslope Cutthroat Trout Oncorhynchus clarkii lewisi ).  In the laboratory, we exposed juvenile fish to a range of CO 2 concentrations for 24-h in unpressurized, flow-through tanks.  A Bayesian hierarchical model was developed to estimate the dose response relationship for each fish species with associated uncertainty, and 24-h LC 50 and LC 95 values were estimated based on laboratory trials for each species.  The minimum concentration inducing mortality differed among cold water-adapted species and warm water-adapted species groups: 150 mg CO 2 /L for Westslope Cutthroat Trout and Rainbow Trout and 225 mg CO 2 /L for Common Carp and Channel Catfish.  We observed complete mortality at 275 mg CO 2 /L (38,672 µatm), 225 mg CO 2 /L (30,711 µatm), and 495 mg CO 2 /L (65,708 µatm (CC); 77,213 µatm (CF)) for Westslope Cutthroat Trout, Rainbow Trout, and both Common Carp and Channel Catfish, respectively.  There was evidence of a statistical difference between the LC 95 values of Westslope Cutthroat Trout and Rainbow Trout (245.0 ( 222.2 to 272.2 ) and 190.6 ( 177.2 to 207.8 ) mg CO 2 /L, respectively).  Additionally, these values were almost half the estimated 24-h LC 95 s for Common Carp and Channel Catfish (422.5 ( 374.7 to 474.5 ) and 434.2 ( 377.2 to 492.2 ) mg CO 2 /L, respectively).  Although the experimental findings show strong relationships between increased CO 2 concentration and higher mortality, additional work is needed to assess the efficacy and feasibility of a CO 2 application in a field setting.

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