Download or read book Patterns of Hybridization Among Cutthroat Trout and Rainbow Trout in Northern Rocky Mountain Streams written by Kevin S. McKelvey and published by . This book was released on 2016 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introgressive hybridization between native and introduced species is a growing conservation concern. For native cutthroat trout and introduced rainbow trout in western North America, this process is thought to lead to the formation of hybrid swarms and the loss of monophyletic evolutionary lineages. Previous studies of this phenomenon, however, indicated that hybrid swarms were rare except when native and introduced forms of cutthroat trout co-occurred. We used a panel of 86 diagnostic, single nucleotide polymorphisms to evaluate the genetic composition of 3865 fish captured in 188 locations on 129 streams distributed across western Montana and northern Idaho. Although introgression was common and only 37% of the sites were occupied solely by parental westslope cutthroat trout, levels of hybridization were generally low. Of the 188 sites sampled, 73% contained ?5% rainbow trout alleles and 58% had ?1% rainbow trout alleles. Overall, 72% of specimens were nonadmixed westslope cutthroat trout, and an additional 3.5% were nonadmixed rainbow trout. Samples from seven sites met our criteria for hybrid swarms, that is, an absence of nonadmixed individuals and a random distribution of alleles within the sample; most (6/7) were associated with introgression by Yellowstone cutthroat trout. In streams with multiple sites, upstream locations exhibited less introgression than downstream locations. We conclude that although the widespread introduction of nonnative trout within the historical range of westslope cutthroat trout has increased the incidence of introgression, sites containing nonadmixed populations of this taxon are common and broadly distributed.

Download or read book Management and Life History Consequences of Hybridization Between Westslope Cutthroat Trout oncorhynchus Clarkii Lewisi and Rainbow Trout oncorhynchus Mykiss written by Matthew Corsi and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The role of introductions of nonnative fishes in the decline of native fishes cannot be overstated. Westslope cutthroat trout (Oncorhynchus clarkii lewisi, WCT) are a salmonid native to the northern Rocky Mountains. These trout hybridize with rainbow trout (O. mykiss, RBT) where they are sympatric; however, in portions of the WCT range where RBT have been introduced, hybridization appears to spread rapidly and threatens continued existence of WCT. The conservation value of these hybridized populations is equivocal, and a better knowledge of the ecological, demographic, behavioral, and genetic consequences of hybridization is needed to better inform conservation strategies. I investigated three related questions: specifically, what landscape factors are associated with estimates of introgression; what are life history differences between WCT and hybrids; and what are tradeoffs in restoring migratory life history in populations threatened by hybridization? The riverscape context plays a substantial role in the distribution of hybrids, as estimates of introgression declined with increases in stream slope, elevation, and distance from a primary source of RBT, three correlated landscape variables. Spatial variation in patterns of hybridization suggests clarifying objectives for sampling and careful designs are necessary to adequately understand the status of populations. Variation in location may relate to some of the ecological differences, such as growth, among fish with different levels of introgression. In the Jocko River, hybrids with ancestry> 20% RBT demonstrated higher growth, earlier migration, increased egg size, and lower fecundity versus WCT. These lines of evidence demonstrate the importance of limiting further hybridization even in populations that already have low levels of hybridization. Given that many unaltered populations currently reside in isolated habitat fragments, I evaluated several demographic tradeoffs of restoring a migratory life history weighed against the risks of increased potential for hybridization from removing barriers or selectively passing migratory fish above the barriers using both matrix and genetic population models. Restoration of migratory life history substantially increases population viability; however, hybridization in above-barrier population increases predictably relative to hybridization status of below-barrier population, which may reduce viability if vital rates are reduced in hybrids. Hybridization creates a challenging set of management problems, but this research adds several important pieces to the puzzles to help develop and evaluate conservation strategies.

Download or read book Climate Change and Rocky Mountain Ecosystems written by Jessica Halofsky and published by Springer. This book was released on 2017-07-19 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the result of a team of approximately 100 scientists and resource managers who worked together for two years to understand the effects of climatic variability and change on water resources, fisheries, forest vegetation, non-forest vegetation, wildlife, recreation, cultural resources and ecosystem services. Adaptation options, both strategic and tactical, were developed for each resource area. This information is now being applied in the northern rocky Mountains to ensure long-term sustainability in resource conditions. The volume chapters provide a technical assessment of the effects of climatic variability and change on natural and cultural resources, based on best available science, including new analyses obtained through modeling and synthesis of existing data. Each chapter also contains a summary of adaptation strategies (general) and tactics (on-the-ground actions) that have been developed by science-management teams.

Download or read book Behavioral Ecological and Fitness Consequences of Hybridization Between Native Westslope Cutthroat Trout Oncorhynchus Clarkii Lewisi and Nonnative Rainbow Trout O Mykiss written by Clint Cain Muhlfeld and published by . This book was released on 2008 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Anthropogenic hybridization is one of the greatest threats to global biodiversity. Hybridization and introgression may lead to a loss of locally adapted gene complexes and ecological adaptations in native populations, yet these potential consequences have not been fully evaluated in nature. I investigated factors influencing the spread of hybridization between native westslope cutthroat trout (Oncorhynchus clarkii lewisi) and nonnative rainbow trout (O. mykiss) in the upper Flathead River system, Montana (USA) and British Columbia (Canada). The fundamental questions of my dissertation were: what are the behavioral, ecological, and fitness consequences of hybridization and what factors influence successful invasion of hybrids? First, I assessed the patterns of spawning between parental species and their hybrids and found that hybridization alters the spawning behavior of migratory westslope cutthroat trout, and is spreading via long distance dispersal of hybrids from downstream sources and some temporal overlap during spawning. Second, I describe for the first time how a wide range of levels of nonnative admixture affect fitness of cutthroat trout in the wild by estimating reproductive success in a recently invaded stream using parentage analysis with multilocus microsatellite markers. Small amounts of hybridization markedly reduced reproductive success, with fitness exponentially declining by ~50% with 20% nonnative genetic admixture. Finally, I evaluated the association of local-habitat features, landscape characteristics, and biotic factors with the spread of hybridization in the system, and found that hybridization increases in streams with warmer water temperatures, high land use disturbance and close proximity to the source of hybridization; however, none of these factors appeared sufficient to prevent further spread. These combined results suggest that hybrids are not only genetically different than westslope cutthroat trout but also have reduced fitness and are ecologically different, and that hybridization is likely to continue to spread if hybrid populations with high amounts of rainbow trout admixture are not reduced or eliminated. I conclude that extant aboriginal cutthroat trout are at greater conservation risk due to hybridization than previously thought and policies that protect hybridized populations need reconsideration.

Download or read book Hybridization Between Yellowstone Cutthroat Trout and Rainbow Trout in the Upper Snake River Basin Wyoming written by Ryan P. Kovach and published by . This book was released on 2011 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Rainbow Trout Oncorhynchus Mykiss Invasion and the Spread of Hybridization with Native Westslope Cutthroat Trout Oncorhynchus Clarkii Lewisi written by Matthew C. Boyer and published by . This book was released on 2008 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: We analyzed 13 microsatellite loci to estimate gene flow among westslope cutthroat trout, Oncorhynchus clarkii lewisi, populations and determine the invasion pattern of hybrids between native O. c. lewisi and introduced rainbow trout, Oncorhynchus mykiss, in streams of the upper Flathead River system, Montana (USA) and British Columbia (Canada). Fourteen of 31 sites lacked evidence of O. mykiss introgression, and gene flow among these nonhybridized O. c. lewisi populations was low, as indicated by significant allele frequency divergence among populations (?ST = 0.076, ?ST = 0.094, P

Download or read book The Grizzly in the Driveway written by Robert Chaney and published by University of Washington Press. This book was released on 2021-01-01 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Four decades ago, the areas around Yellowstone and Glacier National Parks sheltered the last few hundred surviving grizzlies in the Lower 48 states. Protected by the Endangered Species Act, their population has surged to more than 1,500, and this burgeoning number of grizzlies now collides with the increasingly populated landscape of the twenty-first-century American West. While humans and bears have long shared space, today’s grizzlies navigate a shrinking amount of wilderness: cars whiz like bullets through their habitats, tourists check Facebook to pinpoint locations for a quick selfie with a grizzly, and hunters seek trophy prey. People, too, must learn to live and work within a potential predator’s territory they have chosen to call home. Mixing fast-paced storytelling with rich details about the hidden lives of grizzly bears, Montana journalist Robert Chaney chronicles the resurgence of this charismatic species against the backdrop of the country’s long history with the bear. Chaney captures the clash between groups with radically different visions: ranchers frustrated at losing livestock, environmental advocates, hunters, and conservation and historic preservation officers of tribal nations. Underneath, he probes the balance between our demands on nature and our tolerance for risk.

Download or read book Evaluation and Comparison of Stream Habitats and Populations Between Greenback Cutthroat and Rainbow Trout in the Rocky Mountains of Colorado written by Joseph Daniel Mitchell and published by . This book was released on 1978 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hybridization Between Yellowstone Cutthroat Trout and Rainbow Trout Alters the Expression of Muscle Growth Related Genes and Their Relationships with Growth Patterns written by Carl O. Ostberg and published by . This book was released on 2015 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hybridization creates novel gene combinations that may generate important evolutionary novelty, but may also reduce existing adaptation by interrupting inherent biological processes, such as genotype-environment interactions. Hybridization often causes substantial change in patterns of gene expression, which, in turn, may cause phenotypic change. Rainbow trout (Oncorhynchus mykiss) and cutthroat trout (O. clarkii) produce viable hybrids in the wild, and introgressive hybridization with introduced rainbow trout is a major conservation concern for native cutthroat trout. The two species differ in body shape, which is likely an evolutionary adaptation to their native environments, and their hybrids tend to show intermediate morphology. The characterization of gene expression patterns may provide insights on the genetic basis of hybrid and parental morphologies, as well as on the ecological performance of hybrids in the wild. Here, we evaluated the expression of eight growth-related genes (MSTN-1a, MSTN-1b, MyoD1a, MyoD1b, MRF-4, IGF-1, IGF-2, and CAST-L) and the relationship of these genes with growth traits (length, weight, and condition factor) in six line crosses: both parental species, both reciprocal F1 hybrids, and both first-generation backcrosses (F1 x rainbow trout and F1 x cutthroat trout). Four of these genes were differentially expressed among rainbow, cutthroat, and their hybrids. Transcript abundance was significantly correlated with growth traits across the parent species, but not across hybrids. Our findings suggest that rainbow and cutthroat trout exhibit differences in muscle growth regulation, that transcriptional networks may be modified by hybridization, and that hybridization disrupts intrinsic relationships between gene expression and growth patterns that may be functionally important for phenotypic.

Download or read book Geographic Patterns of Introgressive Hybridization Between Native Yellowstone Cutthroat Trout Oncorhynchus Clarki Bouvieri and Introduced Rainbow Trout Oncorhynchus Mykiss written by Kelly Gunnell and published by . This book was released on 2006 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fisheries and Aquaculture of the Temperate Himalayas written by Pramod Kumar Pandey and published by Springer Nature. This book was released on 2023-05-02 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers all aspects of fisheries and aquaculture of the temperate Himalayas, including fisheries resources, fish biodiversity, aquaculture status, prospects, and potential. It also includes mapping of resources, health and disease management of cultured species, feed and nutritional aspects of the cultured fish species, ornamental fisheries aspects, etc. In addition, it elucidates the recent advances in biotechnological interventions for enhancing fisheries and aquaculture productivity in the region. Essential information on the application of Geo Information System (GIS) for resource mapping, the scope of adopting re-circulatory aquaculture system for productivity enhancement, and trout culture in the Himalayan waters are provided in the book. A detailed account of recreational fisheries and fish-based ecotourism in the temperate Himalayas for generating livelihood has been provided. The impact of climate change on the fisheries of the Himalayas has been dealt with separately. The book also covers the conservation and rehabilitation aspects of endangered species of the region. This book will become a ready reference for the scientists, teachers, researchers, students, policymakers, and other stakeholders for managing fishery resources in the temperate Himalayas.

Download or read book Genomic and Fitness Consequences of Hybridization Between Cutthroat and Rainbow Trout written by Daniel P. Drinan and published by . This book was released on 2015 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hybridization is an important and common evolutionary process that can contribute to diversification, adaptation, and speciation. When species hybridize, divergent genomes are combined through recombination and may result in phenotypic changes. Such phenotypic changes may be the result of differences in chromosomal structure or adaptive divergence between the parental species and may ultimately affect fitness. Understanding how phenotypes change following hybridization, as well as the genetic mechanisms responsible for changes is critical for understanding divergent selection, speciation, and identifying populations that may be at risk from hybridization. Here, the effect of hybridization between cutthroat (Oncorhynchus clarkii) and rainbow trout (O. mykiss) on fitness was investigated using three techniques. In the first chapter, fitness influencing traits were compared among individuals at various hybridization levels. In the second chapter, genomic changes that could affect fitness were identified in the hybrid relative to rainbow trout. And, in the third chapter, correlations between reproductive success and hybridization were investigated in a wild population, as well as the genomic and ecological mechanisms responsible for those changes. The first chapter of this dissertation aimed to identify how traits potentially involved in fitness (embryonic survival, ova size, ova energy concentration, sperm motility, burst swimming performance, juvenile survival, and juvenile growth) changed with hybridization between cutthroat and rainbow trout and whether those changes could explain previously observed reductions in reproductive success of individuals with increased rainbow trout ancestry. Using progeny from wild caught fish, differences in phenotypes based on hybridization were observed for embryonic survival, ova energy concentration, juvenile weight, and burst swimming based on ancestry. However, the correlations differed from previously observed patterns of reproductive success and likely do not explain declines in reproductive success associated with hybridization. The second chapter of this dissertation aimed to identify how hybridization affects the genome by identifying genomic regions with changes in recombination rates in the hybrid relative to rainbow trout as well as genomic areas with excess species-specific ancestry in the hybrid. Previous studies of hybridization have observed recombination suppression in genomic regions where structural differences, such as inversions or karyotype differences, exist between parental species. Such regions may retain groups of adaptive alleles. Additionally, adaptive divergence between the parental species may result in alleles that are preferentially selected in the hybrid progeny. Identification of regions with suppressed recombination or excess species-specific ancestry would provide insight into markers that may be important to fitness and that have differentially evolved in each of the parental species. In total, eight and seven chromosomes were identified to have changes in recombination rates in the hybrid female and male relative to O. mykiss. Recombination was suppressed in the hybrids on two chromosomes with known structural differences between the parental species. In addition, changes in recombination rates were observed on five chromosomes with high proportions of duplicated markers and may be due to increased homeologous chromosome pairing. Recombination patterns were similar between the sexes which suggests that hybridization affects recombination in the same way in females and males. Regions of excess species-specific ancestry covered 11 and 10% of the mapped genome in the female and male and regions of excess were evenly split between cutthroat trout and O. mykiss. Genetic drift may be responsible for much of the observed patterns of excess species-specific ancestry, but selection may also play a role. The aim of the third chapter of this dissertation was to identify the fitness consequences of hybridization, mechanisms responsible for the retention of hybridization, and genomic regions correlated with changes in reproductive success in a wild population of westslope cutthroat trout hybridized with non-native rainbow trout. Adult samples from a previous study, collected over a five year period, were sequenced at 3027 loci. Increased admixture from non-native rainbow trout had a strong, negative effect on reproductive success. A decline of 53% was observed for individuals with an increased genetic contribution of 0.20 from rainbow trout. Despite apparent strong selection against rainbow trout ancestry, hybridization appears to be maintained largely by the invasion of rainbow trout from outside populations as well as the relatively high fitness of few hybrid individuals. Ten loci correlated with reproductive success were identified in females. Seven of the ten loci were linked to chromosomes and three were positioned on chromosomes. Loci linked to reproductive success were identified on chromosomes with excess species-specific ancestry in hybrid progeny (RYHyb14 and RYHyb18) as well as chromosomes with a high proportion of duplicated markers (RYHyb02) and known Robertsonian polymorphism (RYHyb20). The research presented in this dissertation will elucidate our understanding of the phenotypic and genetic changes correlated with hybridization between rainbow and cutthroat trout as well as identify genetic and ecological mechanisms that may be responsible for those changes. In addition, results from this study provide insight into differences in adaptive divergence and markers that may be involved in the early stages of speciation in the wild. Results could be used by managers to identify populations that are at risk from hybridization.

Download or read book Genomic Consequences of Hybridization Between Rainbow and Cutthroat Trout written by Carl O. Ostberg and published by . This book was released on 2015 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introgressive hybridization creates novel gene combinations that may generate important evolutionary novelty and thus contribute to biological complexity and diversification. On the other hand, hybridization with introduced species can threaten native species, such as cutthroat trout (Oncorhynchus clarkii) following the introduction of rainbow trout (O. mykiss). While rainbow trout introgression in cutthroat trout is well documented, neither the evolutionary consequences nor conservation implications are well understood. Hybridization between rainbow and cutthroat trout occurs in the context of substantial chromosomal rearrangement, as well incompletely re-diploidized genomes. Rainbow and cutthroat trout are descended from an autopolyploid ancestor, and extensive chromosome arm rearrangements have occurred between the species following their divergence from the last common ancestor. Evidence for incomplete re-diploidization includes the occasional formation of multivalents and duplicated loci occasionally exhibit a mixture of disomic and tetrasomic inheritance. Thus, transmission genetics may be complicated by recombination between homeologs. Here, I evaluated the phenotypic and genetic consequences of introgression between rainbow trout and Yellowstone cutthroat trout (O. clarkii bouvieri) to provide insights into genome processes that may help explain how introgression affects hybrid genome evolution. The overall aim of the first part of this dissertation (Chapters 1 and 2) was to evaluate phenotypic variation and gene expression among parental species and hybrids to gain insight into the genetic basis of hybrid and parental morphologies. We constructed seven line crosses: both parental species, both reciprocal F1 hybrids, first-generation backcrosses, and F2 hybrids. In Chapter 1, we aimed to assess the role of introgression on growth (length and weight gain), morphology, and developmental instability among these seven crosses. Growth was related to the proportion of rainbow trout genome contained within crosses. Rainbow and cutthroat trout were morphologically divergent: rainbow trout were generally robust whereas cutthroat trout were typically more slender and their hybrids tended to be morphologically intermediate, although backcrosses were morphologically more similar to their backcrossing parental species. These differences in growth and body morphology may be maintained, in part, through the regulation of muscle growth-related genes. Therefore, in Chapter 2, we aimed to characterize the expression of muscle growth-related genes and to describe relationships between gene expression and growth patterns among parental species and hybrids to gain insight into the underlying genetic basis of the difference in their body shapes. Our findings suggest that rainbow and cutthroat trout exhibit differences in muscle growth regulation, that transcriptional networks may be modified by hybridization, and that hybridization disrupts intrinsic relationships between gene expression and growth patterns that may be functionally important for phenotypic adaptations. The overall aim of the second part of this dissertation (Chapters 3 and 4) was to assess the genetic consequences of introgression to determine how the genomic architecture of hybrids affects allelic inheritance, and thus their subsequent evolution. In Chapter 3, we generated a genetic linkage map for rainbow-Yellowstone cutthroat trout hybrids to evaluate genome process that may influence introgression genome evolution in hybrid populations. Our results suggest that few genomic incompatibilities exist between rainbow and cutthroat trout, allowing their to genomes introgress freely, with the exception that differences in chromosome arrangement between the species may act as barriers to introgression and enable large portions of non-recombined chromosomes to persist within admixed populations. In Chapter 4, we aimed to determine the effect of incomplete re-diploidization on transmission genetics in hybrids, compared to pure species. We used the parental gametic phase from existing genetic linkage maps to identify the homeologs that recombine, to characterize this recombination, and to verify meiotic models of residual tetrasomic inheritance in autotetraploids. Recombination between homeologs occurred frequently in hybrids and results in the non-random segregation of alleles across extended chromosomal regions as well as extensive double-reduction in hybrid parental gametes. Taken together, the results from Chapters 3 and 4 suggested that chromosome rearrangements and recombination of homeologs could influence genome evolution in admixed populations. The research presented in this dissertation indicated that the evolutionary fate of hybrid genomes is unpredictable. Some of our findings suggest that introgressions proceeds in a predictable fashion in admixed populations; rainbow and cutthroat genomes freely introgress, with the exception that chromosome rearrangements may suppress recombination across large chromosomal regions. However, homeologous recombination during meiosis in hybrids results in unpredictable segregation of chromosomes, and the segregation of these chromosomes may depend on the hybrid generation of each parent within an admixed population. Furthermore, phenotype and gene expression are quantitative traits, and expression of these traits may depend on hybrid genotypes across transcriptional networks that are controlled by genes distributed over the entire genome. Consequently, hybridization may alter transcriptional regulation of genes, resulting in unpredictable gene expression patterns, which, in turn, contribute to the high phenotypic variation in hybrids.

Download or read book General Technical Report RMRS written by and published by . This book was released on 1998 with total page 842 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Temporal Segregation in Spawning Between Yellowstone Cutthroat Trout and Rainbow Trout written by John Martin Fennell and published by . This book was released on 2021 with total page 152 pages. Available in PDF, EPUB and Kindle. Book excerpt: Native cutthroat trout populations in western North America have faced substantial declines in part due to interactions with non-native species. One such interaction, hybridization with introduced rainbow trout, is recognized as one of the most pressing concerns facing native cutthroat trout populations. I explored how one mechanism of reproductive isolation, temporal segregation, may be limiting hybridization between Yellowstone cutthroat trout and rainbow trout in the North Fork Shoshone River drainage in northwest Wyoming. Using data on adult fish spawning migration timing paired with high resolution genomic data, we provide evidence that Yellowstone cutthroat trout spawn on average 2-4.5 weeks later in the drainage than both rainbow trout and Yellowstone cutthroat trout x rainbow trout hybrids (hybrids). Additional data collected on the size and ancestry of juvenile fish in study tributaries provides further evidence that Yellowstone cutthroat trout spawn later in the spawning season compared to rainbow trout and hybrids. I also investigated how changing water temperature and discharge in the drainage throughout the spawning season may explain differences in the timing of spawning migrations between Yellowstone cutthroat trout, rainbow trout, and hybrids. Yellowstone cutthroat trout were more likely to migrate into the spawning tributary on days after the seasonal peak in stream discharge and on days where water temperature stayed at or above 6 degrees Celsius longer. While Yellowstone cutthroat trout are entering spawning tributaries later, on average, than both rainbow trout and hybrids, disproportionately high numbers of rainbow trout and hybrids paired with extended spawning seasons leads to substantial overlap between when Yellowstone cutthroat trout, rainbow trout, and hybrids are spawning in the system. Thus, I conclude that while temporal segregation in spawn timing may play some role in the persistence of unadmixed Yellowstone cutthroat trout in the drainage, additional mechanisms of reproductive isolation likely exist between the two species.

Download or read book Cutthroat written by Pat Trotter and published by Univ of California Press. This book was released on 2008 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cutthroat tells the full story of the genuine native trout of the American West. This new edition, thoroughly revised and updated after 20 years, synthesizes what is currently known about one of our most interesting and colorful fishes, includes much new information on its biology and ecology, asks how it has fared in the last century, and looks toward its future. In a passionate and accessibly written narrative, Patrick Trotter, fly fisher, environmental advocate, and science consultant, details the evolution, natural history, and conservation of each of the cutthroat's races and incorporates more personal reflections on the ecology and environmental history of the West's river ecosystems. The bibliography now includes what may be the most comprehensive and complete set of references available anywhere on the cutthroat trout. Written for anglers, nature lovers, environmentalists, and students, and featuring vibrant original illustrations by Joseph Tomelleri, this is an essential reference for anyone who wants to learn more about this remarkable, beautiful, and fragile western native.

Download or read book Native Trout of Western North America written by Robert J. Behnke and published by . This book was released on 1992 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: