Genetic Status of Isolated Populations of Colorado River Cutthroat Trout (Oncorhynchus Clarkii Pleuriticus) in the North Fork Little Snake River Drainage, Wyoming
Genetic Status of Isolated Populations of Colorado River Cutthroat Trout (Oncorhynchus Clarkii Pleuriticus) in the North Fork Little Snake River Drainage, Wyoming

Author: Rachel Van Horne

Publisher:

Published: 2011

Total Pages:

ISBN-13:

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In many cases of accidental isolation, the populations above the barriers have limited habitat and small population sizes that make them vulnerable to extinction and may hold evolutionary value to the species as a whole. All the isolated populations in the drainage currently have high genetic differentiation among tributaries, low genetic diversity within each tributary, a suggestion of isolation by distance, and effective population sizes that are below the recommendation for long- term persistence. This structure represents natural and anthropogenic influences, but the presence of the human-constructed barriers in the headwater tributaries puts the larger core conservation group at risk into the future. Although the genetic diversities within the populations are low, the high genetic differentiations among populations suggest that each population may have its own unique contribution to the evolutionary value to the drainage as a whole and each is important to conserve into the future.

Conservation Plan for Colorado River Cutthroat Trout (Oncorhynchus Clarki Pleuriticus) for the Little Snake River Drainage, in Southeastern Wyoming
Conservation Plan for Colorado River Cutthroat Trout (Oncorhynchus Clarki Pleuriticus) for the Little Snake River Drainage, in Southeastern Wyoming

Author:

Publisher:

Published: 1994

Total Pages: 49

ISBN-13:

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"The Colorado River cutthroat trout (Oncorhynchus clarki pleuriticus) historically occupied portions of the Colorado River drainage in Wyoming, Colorado, Utah, Arizona, and New Mexico. Today this subspecies only occupies a fraction of its historical range is primarily located in small headwater streams. Colorado River cutthroat trout is a category 2 species (one that may be appropriate for listing as threatened or endangered) by the USDI Fish and Wildlife Service and is considered a sensitive species by Region 2 of the Forest Service. This conservation strategy is a continuation of efforts started in 1987 under a comprehensive management plan for Colorado River cutthroat trout in Wyoming"--Page ii.

Hybridization Between Yellowstone Cutthroat Trout and Rainbow Trout in the Upper Snake River Basin, Wyoming
Hybridization Between Yellowstone Cutthroat Trout and Rainbow Trout in the Upper Snake River Basin, Wyoming

Author: Ryan P. Kovach

Publisher:

Published: 2011

Total Pages: 11

ISBN-13:

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Human-induced hybridization between fish populations and species is a major threat to aquatic biodiversity worldwide and is particularly relevant to management of the subspecies of cutthroat trout Oncorhynchus clarkii. The upper Snake River basin in Wyoming contains one of the largest remaining populations of Yellowstone cutthroat trout O. clarkii bouvieri, a subspecies of special concern throughout its range; however, little is known about levels of hybridization between Yellowstone cutthroat trout and exotic rainbow trout O. mykiss or about the overall genetic population structure for this river basin. There is concern that the Gros Ventre River is a source of hybridization for the Snake River basin. We sampled across the upper Snake River basin to estimate levels of hybridization and population structure and to describe hybrid zone structure and spatial patterns of hybridization throughout the basin. We used this information to help resolve whether the Gros Ventre River was acting as a potential source of hybridization for the upper Snake River basin. We found that Yellowstone cutthroat trout genotypes dominated the river system, but hybridization was detected at low levels in all populations. The Gros Ventre River contained the highest levels of hybridization (population and individual) and displayed evidence of ongoing hybridization between parental genotypes. Levels of hybridization decreased as a function of distance from the Gros Ventre River, suggesting that this population is acting as a source of rainbow trout genes. These patterns were evident despite the fact that levels of genetic connectivity appeared to be higher than those observed in other cutthroat trout populations (global genetic differentiation index F ST = 0.04), and we did not find evidence for genetic isolation by distance. Management actions aimed at reducing the presence of highly hybridized cutthroat trout or rainbow trout individuals in the Gros Ventre River will help to maintain the upper Snake River basin as an important conservation area.

Colorado River Cutthroat Trout (Oncorhynchus Clarkii Pleuriticus)
Colorado River Cutthroat Trout (Oncorhynchus Clarkii Pleuriticus)

Author: Michael K. Young

Publisher:

Published: 2008

Total Pages: 123

ISBN-13:

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The Colorado River cutthroat trout (Oncorhynchus clarkii pleuriticus) was once distributed throughout the colder waters of the Colorado River basin above the Grand Canyon. About 8 percent of its historical range is occupied by unhybridized or ecologically significant populations. It has been petitioned for listing under the Endangered Species Act and is accorded special status by several state and federal agencies. Habitat alteration and nonnative trout invasions led to the extirpation of many populations and impede restoration. Habitat fragmentation exacerbated by climate change is an emerging threat. A strategic, systematic approach to future conservation is likely to be the most successful.