Cutthroat Trout

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

Frank J. Rahel - One of the best experts on this subject based on the ideXlab platform.

  • Movement patterns in inland Cutthroat Trout (Oncorhynchus clarki utah): management and conservation implications
    Canadian Journal of Fisheries and Aquatic Sciences, 2004
    Co-Authors: Amy J Schrank, Frank J. Rahel
    Abstract:

    Knowledge of movement patterns is critical to the management and conservation of inland salmonids. We studied the movements of Bonneville Cutthroat Trout (Oncorhynchus clarki utah) in a drainage in western Wyoming, USA. Our objectives were to (i) characterize the postspawning movement patterns of adult Bonneville Cutthroat Trout, (ii) contrast postspawning and summer movement patterns, and (iii) identify factors that disrupt the movements of Bonneville Cutthroat Trout. Our data showed that postspawning movements of Bonneville Cutthroat Trout formed a continuum, with fish moving from 0.5 to 82.0 km. Postspawning distance was positively related to fish length. Despite the wide range of movement observed during the spring, fish did not move more than 0.5 km during the summer. A road culvert and an irrigation diversion dam did not seem to pose barriers to the upstream movement of Bonneville Cutthroat Trout to headwater spawning areas in the spring. However, 23% of radio-tagged fish in 2000 moved into the irri...

  • Isolation Management with Artificial Barriers as a Conservation Strategy for Cutthroat Trout in Headwater Streams
    Conservation Biology, 2003
    Co-Authors: Douglas C. Novinger, Frank J. Rahel
    Abstract:

    We evaluated the effectiveness of isolation management and stocking to meet protection and en- hancement goals for native Colorado River Cutthroat Trout ( Oncorhynchus clarki pleuriticus ) in Wyoming (U.S.A.). As a management strategy of the Wyoming Game and Fish Department, Cutthroat Trout were isolated upstream of artificial barriers in small headwater streams. Non-native Trout that might have hybridized, competed with, or preyed upon Cutthroat Trout were removed from the isolated reaches, and then Cutthroat Trout of hatchery origin were stocked to augment populations. We monitored the abundance and body condition of Cutthroat Trout for 4-7 years following isolation in four streams with barriers and in two reference streams without barriers. Barriers limited new invasions by non-native Trout, and removals of non-native Trout greatly re- duced their abundance but did not eliminate them (mainly brook Trout ( Salvelinus fontinalis )). Wild cut- throat Trout persisted in low numbers upstream of barriers, but there was no evidence of enhancement of populations. Stocked Cutthroat Trout did not persist upstream of barriers, and many moved downstream over barriers. The body condition of wild Cutthroat Trout was comparable among populations upstream and downstream of barriers and in reference streams. Isolation management provided only short-term benefits by minimizing the risks of hybridization and allowed populations to persist during the study. Removal of non-native Trout and stocking did not enhance wild Cutthroat Trout populations, however, likely because the isolated reaches lacked critical habitat such as the deep pools necessary to sustain large fish. Also, barriers dis- rupt migratory patterns and prevent seasonal use of headwater reaches by adult Cutthroat Trout. Longer-term consequences of isolation include vulnerability to stochastic processes and loss of genetic diversity. Where non-native species pose an immediate threat to the survival of native fishes, isolation in headwater streams may be the only conservation alternative. In such situations, isolated reaches should be as large and diverse as possible, and improvements should be implemented to ensure that habitat requirements are met.

  • Status of Yellowstone Cutthroat Trout in Wyoming Waters
    North American Journal of Fisheries Management, 2000
    Co-Authors: Carter G. Kruse, Wayne A. Hubert, Frank J. Rahel
    Abstract:

    Abstract Most subspecies of interior Cutthroat Trout Oncorhynchus clarki have suffered dramatic declines in range and number. We assessed the status of genetically pure Yellowstone Cutthroat Trout O. clarki bouvieri on predominantly public lands in three major watersheds of northwestern Wyoming (Greybull River and North and South Forks of the Shoshone River) between 1994 and 1997. These river basins encompass the majority of remaining habitat outside of Yellowstone National Park with potential to contain Yellowstone Cutthroat Trout, and little information on them was available. Only 26% of the 104 streams found to contain Trout still support genetically pure Yellowstone Cutthroat Trout. Extant Yellowstone Cutthroat Trout occupied 245 of 822 km of the perennial streams that contained Trout, suggesting native Trout have been displaced by or hybridized with exotic salmonids in nearly three-quarters of the available habitat in these watersheds. The four remaining populations were widely separated in the water...

  • Geomorphic Influences on the Distribution of Yellowstone Cutthroat Trout in the Absaroka Mountains, Wyoming
    Transactions of the American Fisheries Society, 1997
    Co-Authors: Carter G. Kruse, Wayne A. Hubert, Frank J. Rahel
    Abstract:

    Abstract Influences of large-scale abiotic, geomorphic characteristics on distributions of Yellowstone Cutthroat Trout Oncorhynchus clarki bouvieri are poorly understood. We sampled 151 sites on 56 perennial streams in the Greybull–Wood river drainage in northwestern Wyoming to determine the effects of geomorphic variables on Yellowstone Cutthroat Trout distributions. Channel slope, elevation, stream size, and barriers to upstream movement significantly influenced the presence and absence of Yellowstone Cutthroat Trout. Wild populations of Yellowstone Cutthroat Trout were not found upstream of barriers to fish migration, at sites with channel slopes of 10% or greater, or at elevations above 3,182 m. Based on channel slope alone, logistic regression models correctly classified presence or absence of Yellowstone Cutthroat Trout in 83% of study sites. The addition of elevation and stream size in the models increased classification to 87%. Logistic models tested on an independent data set had agreement rates ...

  • SOURCES OF VARIATION IN COUNTS OF MERISTIC FEATURES OF YELLOWSTONE Cutthroat Trout (ONCORHYNCHUS CLARKI BOUVIERI)
    The Great Basin naturalist, 1996
    Co-Authors: Carter G. Kruse, Wayne A. Hubert, Frank J. Rahel
    Abstract:

    ABSTR-\CT.-\Ve determined variability in counts of meristic features (pyloric caecae, vertebrae, pelvic fin rays, gill­ rakers, basibranchial teeth, scales above the lateral line, and scales in the lateral series) of Yellowstone Cutthroat Trout (Oncorhynchus clarki bouderi) by 3 independent readers, by the same reader on 3 different occasions, and among fish from 12 sampling sites within a 650-km2 watershed. Genetic purity of the Cutthroat Trout was determined by elec­ trophoretic analysis. Significant differences in meristic counts were observed among 3 readers and among sampling sites, but not among 3 occasions by a single reader. Scale counts were within the reported range for Yellowstone Cutthroat Trout, but counts of other structures (pyloric caecae, gillrakers, vertebrae) were as similar to rainbow Trout as to Yellowstone cut­ throat Trout. .\'Ieristic counts identified the fish as Cutthroat Trout; however, variation among readers and sampling sites, as well as within the species, limits their use when identif}'ing genetically pure Cutthroat Trout or assessing possible integra­ tion with rainbow Trout.

Steven T. Kalinowski - One of the best experts on this subject based on the ideXlab platform.

  • Genetic status and conservation of Westslope Cutthroat Trout in Glacier National Park
    Transactions of the American Fisheries Society, 2016
    Co-Authors: Clint C. Muhlfeld, Vincent S. D'angelo, Christopher C. Downs, John D. Powell, Stephen J. Amish, Gordon Luikart, Ryan P. Kovach, Matthew C. Boyer, Steven T. Kalinowski
    Abstract:

    AbstractInvasive hybridization is one of the greatest threats to the persistence of Westslope Cutthroat Trout Oncorhynchus clarkii lewisi. Large protected areas, where nonhybridized populations are interconnected and express historical life history and genetic diversity, provide some of the last ecological and evolutionary strongholds for conserving this species. Here, we describe the genetic status and distribution of Westslope Cutthroat Trout throughout Glacier National Park, Montana. Admixture between Westslope Cutthroat Trout and introduced Rainbow Trout O. mykiss and Yellowstone Cutthroat Trout O. clarkii bouvieri was estimated by genotyping 1,622 fish collected at 115 sites distributed throughout the Columbia, Missouri, and South Saskatchewan River drainages. Currently, Westslope Cutthroat Trout occupy an estimated 1,465 km of stream habitat and 45 lakes (9,218 ha) in Glacier National Park. There was no evidence of introgression in samples from 32 sites along 587 km of stream length (40% of the stre...

  • Genetic variation in westslope Cutthroat Trout Oncorhynchus clarkii lewisi: implications for conservation
    Conservation Genetics, 2011
    Co-Authors: Daniel P. Drinan, Steven T. Kalinowski, Clint C. Muhlfeld, Bradley B. Shepard, Matthew R. Campbell
    Abstract:

    Twenty-five populations of westslope Cutthroat Trout from throughout their native range were genotyped at 20 microsatellite loci to describe the genetic structure of westslope Cutthroat Trout. The most genetic diversity (heterozygosity, allelic richness, and private alleles) existed in populations from the Snake River drainage, while populations from the Missouri River drainage had the least. Neighbor-joining trees grouped populations according to major river drainages. A great amount of genetic differentiation was present among and within all drainages. Based on Nei’s DS, populations in the Snake River were the most differentiated, while populations in the Missouri River were the least. This pattern of differentiation is consistent with a history of sequential founding events through which westslope Cutthroat Trout may have experienced a genetic bottleneck as they colonized each river basin from the Snake to the Clark Fork to the Missouri river. These data should serve as a starting point for a discussion on management units and possible distinct population segments. Given the current threats to the persistence of westslope Cutthroat Trout, and the substantial genetic differentiation between populations, these topics warrant attention.

  • Diagnostic single nucleotide polymorphisms for identifying westslope Cutthroat Trout (Oncorhynchus clarki lewisi), Yellowstone Cutthroat Trout (Oncorhynchus clarkii bouvieri) and rainbow Trout (Oncorhynchus mykiss)
    Molecular ecology resources, 2010
    Co-Authors: Steven T. Kalinowski, B. J. Novak, Daniel P. Drinan, R. Dem Jennings
    Abstract:

    We describe 12 diagnostic single nucleotide polymorphism (SNP) assays for use in species identification among rainbow and Cutthroat Trout: five of these loci have alleles unique to rainbow Trout (Oncorhynchus mykiss), three unique to westslope Cutthroat Trout (O. clarkii lewisi) and four unique to Yellowstone Cutthroat Trout (O. clarkii bouvieri). These diagnostic assays were identified using a total of 489 individuals from 26 populations and five fish hatchery strains.

  • Twelve tetranucleotide microsatellite loci for westslope Cutthroat Trout Oncorhynchusclarkilewisi (Salmonidae)
    Conservation Genetics Resources, 2009
    Co-Authors: Steven T. Kalinowski
    Abstract:

    We isolated 12 tetra-nucleotide microsatellite loci from westslope Cutthroat Trout (Oncorhynchusclarkilewisi). These loci were tested against 58 individuals from a single creek for polymorphism. The number of alleles ranged from 2 to 8, with an average of 4.3. The expected heterozygosity ranged from 0.12 to 0.79, with an average of 0.52. Ten of the twelve loci conformed to Hardy–Weinberg expectations. These microsatellite loci will be useful for describing population structure in westslope Cutthroat Trout.

Victoria L. Pritchard - One of the best experts on this subject based on the ideXlab platform.

  • Discovery and characterization of novel genetic markers for coastal Cutthroat Trout (Oncorhynchus clarkii clarkii)
    Conservation Genetics Resources, 2013
    Co-Authors: Victoria L. Pritchard, John Carlos Garza
    Abstract:

    Coastal Cutthroat Trout (Oncorhynchus clarkii clarkii), native to the west coast of North America, has declined over much of its range. Population genetic studies can aid conservation, but few suitable markers have been available. We describe 62 novel single nucleotide polymorphism (SNP) markers variable in coastal Cutthroat Trout. We additionally show that 22 SNPs previously identified in other taxa are also polymorphic in the subspecies. These 84 SNP assays are the first to be developed for coastal Cutthroat Trout and will be a useful tool in coastal Cutthroat Trout management.

  • Discovery and characterization of novel genetic markers for use in the management of Lahontan Cutthroat Trout (Oncorhynchus clarkii henshawi).
    Molecular ecology resources, 2012
    Co-Authors: Victoria L. Pritchard, Nathan R. Campbell, Shawn R. Narum, Mary M. Peacock, John Carlos Garza
    Abstract:

    The Lahontan Cutthroat Trout (Oncorhynchus clarkii henshawi) is threatened by habitat destruction, over-harvest and hybridization with nonnative Trout. Currently, three Geographic Management Units (GMUs) are recognized within the taxon. Here, we describe a suite of 68 single-nucleotide polymorphism (SNP) genetic markers for use in the study and management of Lahontan Cutthroat Trout and a closely related subspecies, the Paiute Cutthroat Trout (O. c. seleneris). These include markers variable within the two subspecies (n = 35), diagnostic for the two subspecies (n = 23) and diagnostic for Yellowstone Cutthroat Trout (O. c. bouvieri) and other closely related subspecies (n = 10). Sixty-three markers were discovered by Sanger sequencing of 171 EST loci in an ascertainment panel including Lahontan Cutthroat Trout from four populations representing all GMUs. Five markers were identified in a secondary sequencing effort with a single population of Lahontan Cutthroat Trout. TaqMan assays were validated on six Lahontan Cutthroat Trout populations and a diverse panel of other Trout. Over 90% of the markers variable in Lahontan Cutthroat Trout were polymorphic in at least two populations, and 66% were variable within all three GMUs. All Lahontan diagnostic markers were also fixed for the Lahontan allele in Paiute Cutthroat Trout. Most of the Yellowstone diagnostic markers can also be used for this purpose in other Cutthroat Trout subspecies. This is the first set of SNP markers to be developed for Lahontan Cutthroat Trout, and will be an important tool for conservation and management.

  • Across the great divide: genetic forensics reveals misidentification of endangered Cutthroat Trout populations.
    Molecular ecology, 2007
    Co-Authors: Jessica L. Metcalf, Dennis K. Shiozawa, Victoria L. Pritchard, David E. Cowley, Sarah M. Silvestri, Jazzmin B. Jenkins, John S. Wood, R. Paul Evans, Andrew P. Martin
    Abstract:

    Accurate assessment of species identity is fundamental for conservation biology. Using molecular markers from the mitochondrial and nuclear genomes, we discovered that many putatively native populations of greenback Cutthroat Trout (Oncorhynchus clarkii stomias) comprised another subspecies of Cutthroat Trout, Colorado River Cutthroat Trout (Oncorhynchus clarkii pleuriticus). The error can be explained by the introduction of Colorado River Cutthroat Trout throughout the native range of greenback Cutthroat Trout in the late 19th and early 20th centuries by fish stocking activities. Our results suggest greenback Cutthroat Trout within its native range is at a higher risk of extinction than ever before despite conservation activities spanning more than two decades.

  • Characterization of tetranucleotide microsatellites for Rio Grande Cutthroat Trout and rainbow Trout, and their cross‐amplification in other Cutthroat Trout subspecies
    Molecular Ecology Notes, 2007
    Co-Authors: Victoria L. Pritchard, Kenneth L. Jones, Jessica L. Metcalf, Andrew P. Martin, P. Wilkinson, David E. Cowley
    Abstract:

    We describe the isolation and characterization of 12 tetranucleotide microsatellites for Rio Grande Cutthroat Trout (Oncorhynchus clarkii virginalis) and rainbow Trout (Oncorhynchus mykiss), and subsequently investigate their performance in Colorado River Cutthroat Trout (Oncorhynchus clarkii pleuriticus), greenback Cutthroat Trout (Oncorhynchus clarkii stomias) and Yellowstone Cutthroat Trout (Oncorhynchus clarki bouvieri). All 12 loci are polymorphic in all subspecies of O. clarkii examined.

Matthew R. Campbell - One of the best experts on this subject based on the ideXlab platform.

  • Purifying a Yellowstone Cutthroat Trout Stream by Removing Rainbow Trout and Hybrids via Electrofishing
    Transactions of the American Fisheries Society, 2017
    Co-Authors: Kevin A. Meyer, Patrick Kennedy, Brett High, Matthew R. Campbell
    Abstract:

    AbstractThe South Fork of the Snake River in Idaho supports one of the few remaining fluvial populations of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri, but long-term persistence of Cutthroat Trout in the drainage is threatened by introgression with introduced Rainbow Trout O. mykiss. We completed eight backpack electrofishing removals from 2010 to 2015 to remove Rainbow Trout and Rainbow Trout × Cutthroat Trout hybrids from a 9.3-km isolated reach of Palisades Creek (a tributary of the South Fork) in an attempt to improve the purity of the population. For two removals, fish from a subsample of Oncorhynchus were genetically screened at seven diagnostic nuclear DNA loci. A total of 14,092 fish were captured across all removals, of which 3,446 were putative Rainbow Trout or hybrids, which were removed from the stream. The proportion of the total catch that Yellowstone Cutthroat Trout comprised (across all size-classes combined) increased slowly over time, from 67% in 2010 to 86% for the second...

  • Distinguishing Yellowstone Cutthroat Trout, Rainbow Trout, and Hybrids by Use of Field‐Based Phenotypic Characteristics
    North American Journal of Fisheries Management, 2017
    Co-Authors: Kevin A. Meyer, Patrick Kennedy, Brett High, Matthew R. Campbell
    Abstract:

    AbstractNative and nonnative salmonids within the same genus sometimes hybridize, and the hybrids are often difficult to visually distinguish from parental species. We compared phenotypic delineations (based on several visual characteristics) and genotypic screening (using seven nuclear DNA loci) for 323 fish collected from an Idaho stream where Yellowstone Cutthroat Trout O. clarkii bouvieri were introgressed with Rainbow Trout O. mykiss to evaluate our ability to visually distinguish Yellowstone Cutthroat Trout from Rainbow Trout and hybrids. Assuming that the genotypes were 100% accurate, correct phenotypic classification was highest for Yellowstone Cutthroat Trout (the genotype confirmed the phenotype 94% of the time), followed by hybrids (79%) and Rainbow Trout (71%). All errors were between pure and hybrid fish. All of the measured phenotypic characteristics were useful for differentiating Yellowstone Cutthroat Trout from hybrids, but the most informative characteristics were the lack of a white lea...

  • STATUS UPDATES FOR YELLOWSTONE Cutthroat Trout, REDBAND Trout, AND BULL Trout IN IDAHO
    2013
    Co-Authors: Kevin A. Meyer, Daniel J. Schill, Matthew R. Campbell, Christine C. Kozfkay, Erin I. Larson, Christopher L. Sullivan, Elizabeth R. J. M. Mamer, Edward O. Garton
    Abstract:

    The distribution and abundance of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri across their native range is relatively well known, but evaluations of trends in distribution and abundance over time are lacking. In 2010-2011, we resurveyed 74 stream reaches in the upper Snake River basin of Idaho that were previously sampled in the 1980s and again in 1999-2000 to evaluate changes in the distribution and abundance of Yellowstone Cutthroat Trout and nonnative Trout over time. Yellowstone Cutthroat Trout occupied all 74 reaches in the 1980s, 70 reaches in 1999-2000, and 69 reaches in 2010-2011. In comparison, rainbow Trout O. mykiss and rainbow x Cutthroat hybrid occupancy increased from 23 reaches in the 1980s to 36 reaches in 1999-2000, and then declined to 23 reaches in 2010-2011. Brown Trout Salmo trutta and brook Trout Salvelinus fontinalis occupancy was largely unchanged across time periods. Yellowstone Cutthroat Trout abundance declined from a mean of 40.0 fish/100 linear meters of stream in the 1980s to 32.8 fish/100 m in 2010-2011. In contrast, abundance increased over time for all species of nonnative Trout, although the change was statistically significant (at α = 0.10) only for brown Trout. Population growth rate (λ) was below replacement for Yellowstone Cutthroat Trout (0.98) and above replacement (>1.00) for all nonnative Trout, but 90% confidence intervals overlapped unity for all species. However, population growth differed statistically from 1.00 within several individual drainages for each species. More pronounced drought conditions in any given year resulted in lower Yellowstone Cutthroat Trout abundance one year later. Our results suggest that over a span of up to 32 years, the distribution and abundance of Yellowstone Cutthroat Trout in the upper Snake River basin appears to be relatively stable, and nonnative Trout do not currently appear to be displacing Yellowstone Cutthroat Trout across the landscape.

  • Genetic variation in westslope Cutthroat Trout Oncorhynchus clarkii lewisi: implications for conservation
    Conservation Genetics, 2011
    Co-Authors: Daniel P. Drinan, Steven T. Kalinowski, Clint C. Muhlfeld, Bradley B. Shepard, Matthew R. Campbell
    Abstract:

    Twenty-five populations of westslope Cutthroat Trout from throughout their native range were genotyped at 20 microsatellite loci to describe the genetic structure of westslope Cutthroat Trout. The most genetic diversity (heterozygosity, allelic richness, and private alleles) existed in populations from the Snake River drainage, while populations from the Missouri River drainage had the least. Neighbor-joining trees grouped populations according to major river drainages. A great amount of genetic differentiation was present among and within all drainages. Based on Nei’s DS, populations in the Snake River were the most differentiated, while populations in the Missouri River were the least. This pattern of differentiation is consistent with a history of sequential founding events through which westslope Cutthroat Trout may have experienced a genetic bottleneck as they colonized each river basin from the Snake to the Clark Fork to the Missouri river. These data should serve as a starting point for a discussion on management units and possible distinct population segments. Given the current threats to the persistence of westslope Cutthroat Trout, and the substantial genetic differentiation between populations, these topics warrant attention.

  • Status of yellowstone Cutthroat Trout in Idaho
    Transactions of the American Fisheries Society, 2006
    Co-Authors: Kevin A. Meyer, Daniel J. Schill, James A. Lamansky, Matthew R. Campbell, Christine C. Kozfkay
    Abstract:

    Abstract In this study, we electrofished 961 study sites to estimate the abundance of Trout (in streams only) throughout the upper Snake River basin in Idaho (and portions of adjacent states) to determine the current status of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvierii and other nonnative salmonids and to assess introgressive hybridization between Yellowstone Cutthroat Trout and rainbow Trout O. mykiss. Yellowstone Cutthroat Trout were the most widely distributed species of Trout, followed by brook Trout Salvelinus fontinalis, rainbow Trout and rainbow Trout × Yellowstone Cutthroat Trout hybrids, and brown Trout Salmo trutta. Of the 457 sites that contained Yellowstone Cutthroat Trout, less than half also contained nonnative salmonids and only 88 contained rainbow Trout and hybrids. In the 11 geographic management units (GMUs) for which sample size permitted abundance estimates, the number of 100-mm and larger Trout was estimated to be about 2.2 ± 1.2 million (mean ± confidence interval); ...

Kurt D. Fausch - One of the best experts on this subject based on the ideXlab platform.

  • Cold Summer Temperature Limits Recruitment of Age-0 Cutthroat Trout in High-Elevation Colorado Streams
    Transactions of the American Fisheries Society, 2007
    Co-Authors: Mark A. Coleman, Kurt D. Fausch
    Abstract:

    Abstract Translocation is a key strategy for conserving native subspecies of Cutthroat Trout Oncorhynchus clarkii that have declined markedly throughout their native range. Previous research showed that successful translocations of Cutthroat Trout in high-elevation southern Rocky Mountain streams were more likely in streams with warm summer water temperature and led to the hypothesis that cold summer temperatures govern translocation success by limiting recruitment. We tested this by measuring the density and size of age-0 Cutthroat Trout (greenback Cutthroat Trout O. c. stomias and Colorado River Cutthroat Trout O. c. pleuriticus) in six headwater streams in north-central Colorado that varied in thermal characteristics. Surveys were conducted at peak emergence during 3 years in two widely spaced study reaches in each stream. Fry density increased with Celsius degree-days accumulated during the growing season but did not vary significantly among years. We used laboratory data on the growth and survivorshi...

  • POPULATION ECOLOGY OF AN INVASION: EFFECTS OF BROOK Trout ON NATIVE Cutthroat Trout
    Ecological Applications, 2004
    Co-Authors: Douglas P. Peterson, Kurt D. Fausch, Gary C. White
    Abstract:

    Invasion by nonnative brook Trout (Salvelinus fontinalis) often results in replacement of Cutthroat Trout (Oncorhynchus clarki) in the inland western United States, but the underlying mechanisms are not well understood. We conducted a four-year removal experiment to test for population-level mechanisms (i.e., changes in recruitment, survival, emigration, and immigration) promoting invasion success of brook Trout and causing decline of native Colorado River Cutthroat Trout (O. c. pleuriticus). We chose 700–1200 m segments of four small mountain streams where brook Trout had recently invaded Cutthroat Trout populations, two each at mid elevation (2500–2700 m) and high elevation (3150–3250 m), and annually removed brook Trout from two streams (treatments), but not the other two (controls). We used depletion electrofishing, two-way fish weirs, and mark–recapture methods to estimate abundance, movement, and survival of Trout. At mid elevation, age-0 and age-1 Cutthroat Trout survived at 13 times and two times ...

  • minimum habitat requirements for establishing translocated Cutthroat Trout populations
    Ecological Applications, 2002
    Co-Authors: Amy L. Harig, Kurt D. Fausch
    Abstract:

    Translocation is an important management strategy in conservation programs for endangered or threatened species, including native Cutthroat Trout (Oncorhynchus clarki) in the western United States. Most subspecies of Cutthroat Trout have declined to <5% of their historical range, and both historical and translocated populations now persist in small isolated fragments of habitat. Success rates for translocations of fishes are generally <50%, and habitat quality or quantity are frequently cited as the cause of failure. Therefore, we conducted field surveys of stream-scale habitat and measured basin-scale habitat using a Geographic Information System for 27 streams where two subspecies of Cutthroat Trout were translocated in Colorado and New Mexico, to identify specific habitat attributes that contribute to the success of translocations. We used polytomous logistic regression to develop models that predict three categories of Cutthroat Trout translocation success (high, low, absent) from habitat attributes at two spatial scales. Models based on stream-scale habitat attributes indicated that cold summer water temperature, narrow stream width, and lack of deep pools limited translocations of Cutthroat Trout. Cold summer temperatures are known to delay spawning and prolong egg incubation, which reduces the growth of fry and likely limits their overwinter survival. Furthermore, small streams with few deep pools may lack the space necessary to permit overwinter survival of a sufficient number of individuals to sustain a population. Models based on basin-scale habitat were not as effective as stream-scale habitat models for dis- tinguishing among translocation sites with high, low, or absent population status but in- dicated that a minimum watershed area of 14.7 km2 was useful as a coarse filter for separating sites with high numbers of Cutthroat Trout from those with low or absent status. Watersheds larger than this are expected to encompass low-elevation habitat that provides warmer summer temperatures and to have relatively wide stream channels of sufficient length to provide an adequate number of deep pools. These results indicate that the appropriate scale of habitat measurement for predicting Cutthroat Trout translocation success in fragmented watersheds is at the patch rather than landscape scale, which is similar to results for other salmonids and vertebrate taxa in general.

  • MINIMUM HABITAT REQUIREMENTS FOR ESTABLISHING TRANSLOCATED Cutthroat Trout POPULATIONS
    Ecological Applications, 2002
    Co-Authors: Amy L. Harig, Kurt D. Fausch
    Abstract:

    Translocation is an important management strategy in conservation programs for endangered or threatened species, including native Cutthroat Trout (Oncorhynchus clarki) in the western United States. Most subspecies of Cutthroat Trout have declined to

  • Factors Influencing Success of Greenback Cutthroat Trout Translocations
    North American Journal of Fisheries Management, 2000
    Co-Authors: Amy L. Harig, Kurt D. Fausch, Michael K. Young
    Abstract:

    Abstract Native subspecies of Cutthroat Trout Oncorhynchus clarki have declined drastically because of the introduction of nonnative salmonids, overharvesting, and habitat degradation. Conservation of most declining subspecies will include establishing new populations through translocation of genetically pure fish. Recovery of greenback Cutthroat Trout O. clarki stomias has been ongoing for 25 years, so the attempted translocations of this subspecies provide unique empirical information to guide recovery of other nonanadromous salmonids. We compared 14 translocations that successfully established populations of greenback Cutthroat Trout to 23 that failed to determine the factors that influenced translocation success. Of the translocations that failed, 48% were reinvaded by nonnative salmonids, 43% apparently had unsuitable habitat, and 9% experienced suppression by other factors. Reinvasion occurred most often because of failed artificial barriers or incomplete removal of nonnative salmonids in complex ha...

Related terms

Cutthroat Trout - 15 days free trial to Access Experts & Abstracts