Loading...
Please wait, while we are loading the content...
Similar Documents
Spatial and temporal spawning dynamics of native westslope cutthroat trout, Oncorhynchus clarkii lewisi, introduced rainbow trout, Oncorhynchus mykiss, and their hybrids.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Muhlfeld, Clint C. McMahon, Thomas E. Belcer, Durae Belcer D. Kershner, Jeffrey L. |
| Copyright Year | 2009 |
| Abstract | 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 hy- brids (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 pro- vides 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. Resume ´ : La radiotelemetrie nous a servi aevaluer la repartition spatiale et temporelle de la fraie chez la truite fardee in- digene du versant occidental (Oncorhynchus clarkii lewisi; WCT), la truite arc-en-ciel (Oncorhynchus mykiss; RBT) intro- duite et leurs hybrides dans le reseau hydrographique superieur de la Flathead au Montana (E ´ .-U.) et en Colombie- Britannique (Canada) de 2000 a ` 2007. Les truites porteuses d'une etiquette radio (N = 125) se sont deplacees vers l'amont vers les sites de fraie durant la crue printaniere et ont frayedans 29 tributaires. Les WCT ont migresur de plus grandes distances et ont frayedans les cours d'eau les plus en amont durant les debits maxima et durant la reduction des debits, alors que les RBT et les hybrides RBT (retrocroises avec RBT) ont frayeplus tot durant l'augmentation des debits et plus en aval dans le bassin. Les hybrides WCT (retrocroises avec WCT) ont eu une fraie intermediaire dans le temps et l'espace a celles des WCT, des RBT et leurs hybrides RBT. Cependant, les deux groupes d'hybrides et RBT ont frayedu- rant des periodes qui chevauchent la fraie des WCT la plupart des annees. Nos donnees indiquent que l'hybridation se propage grace aux deplacements sur de longues distances vers les cours d'eau a WCT d'individus qui possedent un fort complement de RBT et par une invasion par degres par les generations subsequentes retrocroisees. Notre etude fournit des preuves que l'hybridation augmente la probabilitede chevauchement reproductif dans le temps et l'espace, ce qui favorise l'extinction par introgression; la propagation de l'hybridation va vraisemblablement continuer amoins que la source de populations d'hybrides ne soit reduite ou eliminee. (Traduit par la Redaction) |
| Starting Page | 1153 |
| Ending Page | 1168 |
| Page Count | 16 |
| File Format | PDF HTM / HTML |
| DOI | 10.1139/F09-073 |
| Volume Number | 66 |
| Alternate Webpage(s) | http://www.flatheadtu.org/indexFiles/WebDocs/CT3.pdf |
| Alternate Webpage(s) | http://www.montana.edu/mcmahon/Muhlfeld%20et%20al%20(CJAFS)_2009.pdf |
| Alternate Webpage(s) | https://doi.org/10.1139/F09-073 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
