scholarly journals Diet overlap among non‐native trout species and native cutthroat Trout ( Oncorhynchus clarkii) in two U.S. ecoregions

2021 ◽  
Vol 11 (6) ◽  
pp. 2782-2795
Author(s):  
Mario Minder ◽  
Emily R. Arsenault ◽  
Bolortsetseg Erdenee ◽  
Alain Maasri ◽  
Mark Pyron
Keyword(s):  
Cutthroat Trout ◽  
Diet Overlap ◽  
Oncorhynchus Clarkii

Metabolic performance and thermal preference of Westslope Cutthroat Trout Oncorhynchus clarkii lewisi and non-native trout across an ecologically relevant range of temperatures

2021 ◽  
Author(s):  
Camille J. Macnaughton ◽  
Travis C. Durhack ◽  
Neil J. Mochnacz ◽  
Eva C. Enders
Keyword(s):  
Brook Trout ◽  
Cold Water ◽  
Cutthroat Trout ◽  
Intermittent Flow ◽  
Performance Curve ◽  
Westslope Cutthroat Trout ◽  
Oncorhynchus Clarkii ◽  
Thermal Niche ◽  
Preferred Temperatures ◽  
Metabolic Performance

The physiology and behaviour of fish are strongly affected by ambient water temperature. Physiological traits related to metabolism, such as aerobic scope (AS), can be measured across temperature gradients and the resulting performance curve reflects the thermal niche that fish can occupy. We measured AS of Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi) at 5, 10, 15, 20, and 22°C and compared temperature preference (Tpref) of the species to non-native Brook Trout, Brown Trout, and Rainbow Trout. Intermittent-flow respirometry experiments demonstrated that metabolic performance of Westslope Cutthroat Trout was optimal at ~15 °C and decreased substantially beyond this temperature, until lethal temperatures at ~25 °C. Adjusted preferred temperatures across species (Tpref) were comparatively high, ranging from 17.8-19.9 °C, with the highest Tpref observed for Westslope Cutthroat Trout. Results suggest that although Westslope Cutthroat Trout is considered a cold-water species, they do not prefer or perform as well in cold water (≤ 10°C), thus, can occupy a warmer thermal niche than previously thought. The metabolic performance curve (AS) can be used to develop species‐specific thermal criteria to delineate important thermal habitats and guide conservation and recovery actions for Westslope Cutthroat Trout.

scholarly journals Hybridization of Snake River Cutthroat in the Lower Gros Ventre River

2006 ◽  
Vol 30 ◽  
pp. 110-113
Author(s):  
Ryan Kovach ◽  
Lisa Eby
Keyword(s):  
Exotic Species ◽  
National Park ◽  
Cutthroat Trout ◽  
Snake River ◽  
Oncorhynchus Clarki ◽  
Oncorhynchus Clarkii ◽  
Grand Teton National Park ◽  
Water Diversions ◽  
Yellowstone Cutthroat Trout ◽  
Special Concern

The cutthroat trout Oncorhynchus clarki is Wyoming's only native trout. The Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) is designated as a "species of special concern" by a number of agencies and conservation groups. Although the Yellowstone cutthroat trout has recently avoided federal listing because of robust headwater populations (USFWS 2006), they face continued threats across their range. The fine-spotted Snake River native trout is a morphologically divergent ecotype of the Yellowstone subspecies, although it is not genetically distinguishable (Allendorf and Leary 1988, Novak et al. 2005). The Gros Ventre, an important tributary of the Snake River located partially in Grand Teton National Park, historically supported robust populations of fine­ spotted Snake River cutthroat trout. Principal threats to Gros Ventre native trout, especially in the lower end of the drainage within the park boundaries, include both water diversions (loss of water and fish into irrigation ditches) and presence of exotic species.

Morphological and genetic concordance of cutthroat trout diversification from western North America

2021 ◽  
Author(s):  
Ernest R Keeley ◽  
Janet L Loxterman ◽  
Sammy L Matsaw ◽  
Zacharia M Njoroge ◽  
Meredith B Seiler ◽  
...  
Keyword(s):  
North America ◽  
Phenotypic Variability ◽  
Sequence Divergence ◽  
Cutthroat Trout ◽  
Distance Measures ◽  
Western North America ◽  
Morphological Comparison ◽  
Oncorhynchus Clarkii ◽  
Diverse Range ◽  
Mtdna Sequence

The cutthroat trout, Oncorhynchus clarkii (Richardson, 1836), is one of the most widely distributed species of freshwater fish in western North America. Occupying a diverse range of habitats, they exhibit significant phenotypic variability that is often recognized by intraspecific taxonomy. Recent molecular phylogenies have described phylogenetic diversification across cutthroat trout populations, but no study has provided a range-wide morphological comparison of taxonomic divisions. In this study, we used linear and geometric-based morphometrics to determine if phylogenetic and subspecies divisions correspond to morphological variation in cutthroat trout, using replicate populations from throughout the geographic range of the species. Our data indicate significant morphological divergence of intraspecific categories in some, but not all, cutthroat trout subspecies. We also compare morphological distance measures with distance measures of mtDNA sequence divergence. DNA sequence divergence was positively correlated with morphological distance measures, indicating that morphologically more similar subspecies have lower sequence divergence in comparison to morphologically distant subspecies. Given these results, integrating both approaches to describing intraspecific variation may be necessary for developing a comprehensive conservation plan in wide-ranging species.

The interactive effects of stream temperature, stream size, and non-native species on Yellowstone cutthroat trout

2021 ◽  
Author(s):  
Robert Al-Chokhachy ◽  
Mike Lien ◽  
Bradley B. Shepard ◽  
Brett High
Keyword(s):  
Native Species ◽  
Cutthroat Trout ◽  
Population Level ◽  
Stream Temperature ◽  
Interactive Effects ◽  
Oncorhynchus Clarkii ◽  
Wide Range ◽  
Yellowstone Cutthroat Trout ◽  
Stream Size ◽  
Native Salmonids

Climate change and non-native species are considered two of the biggest threats to native salmonids in North America. We evaluated how non-native salmonids and stream temperature and discharge were associated with Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) distribution, abundance, and body size, to gain a more complete understanding of the existing threats to native populations. Allopatric Yellowstone cutthroat trout were distributed across a wide range of average August temperatures (3.2 to 17.7ºC), but occurrence significantly declined at colder temperatures (<10 ºC) with increasing numbers of non-natives. At warmer temperatures occurrence remained high, despite sympatry with non-natives. Yellowstone cutthroat trout relative abundance was significantly reduced with increasing abundance of non-natives, with the greatest impacts at colder temperatures. Body sizes of large Yellowstone cutthroat trout (90th percentile) significantly increased with warming temperatures and larger stream size, highlighting the importance of access to these more productive stream segments. Considering multiple population-level attributes demonstrates the complexities of how native salmonids (such as Yellowstone cutthroat trout) are likely to be affected by shifting climates.

Cutthroat Trout: Evolutionary Biology and Taxonomy

2018 ◽  
Keyword(s):  
Evolutionary Biology ◽  
Cutthroat Trout ◽  
Westslope Cutthroat Trout ◽  
Oncorhynchus Clarkii ◽  
Coastal Cutthroat Trout ◽  
Lahontan Cutthroat Trout ◽  
Museum Samples ◽  
Yellowstone Cutthroat Trout ◽  
The 1960S

<em>Abstract</em>.—There has been considerable interest in the systematics and classification of Cutthroat Trout since the 1800s. Cutthroat Trout native to western North America (currently classified as <em>Oncorhynchus clarkii</em>) have historically been grouped or separated using many different classification schemes. Since the 1960s, Robert Behnke has been a leader in these efforts. Introductions of nonnative trout (other forms of Cutthroat Trout, and Rainbow Trout <em>O. mykiss</em>) have obscured some historical patterns of distribution and differentiation. Morphological and meristic analyses have often grouped the various forms of Cutthroat Trout together based on the shared presence of the “cutthroat mark,” high scale counts along the lateral line, and the presence of basibranchial teeth. Spotting patterns and counts of gill rakers and pyloric caeca have in some cases been helpful in differentiation of groups (e.g., Coastal Cutthroat Trout <em>O. c. clarkii</em>, Lahontan Cutthroat Trout <em>O. c. henshawi</em>, and Westslope Cutthroat Trout <em>O. c. lewisi</em>) currently classified as subspecies. The historical genetic methods of allozyme genotyping through protein electrophoresis and chromosome analyses were often helpful in differentiating the various subspecies of Cutthroat Trout. Allozyme genotyping allowed four major groups to be readily recognized (Coastal Cutthroat Trout, Westslope Cutthroat Trout, the Lahontan Cutthroat Trout subspecies complex, and Yellowstone Cutthroat Trout <em>O. c. bouvieri </em>subspecies complex) while chromosome analyses showed similarity between the Lahontan and Yellowstone Cutthroat trout subspecies complex trout (possibly reflecting shared ancestral type) and differentiated the Coastal and Westslope Cutthroat trouts from each other and those two groups. DNA results may yield higher resolution of evolutionary relationships of Cutthroat Trout and allow incorporation of ancient museum samples. Accurate resolution of taxonomic differences among various Cutthroat Trout lineages, and hybridization assessments, requires several approaches and will aid in conservation of these charismatic and increasingly rare native fishes.

Cutthroat Trout: Evolutionary Biology and Taxonomy

2018 ◽  
Keyword(s):  
Rainbow Trout ◽  
Rocky Mountains ◽  
Evolutionary Biology ◽  
Cutthroat Trout ◽  
Taxonomic Revision ◽  
River Basins ◽  
Evidence Based ◽  
Oncorhynchus Clarkii ◽  
Southern Rocky Mountains ◽  
Green Lineage

<em>Abstract</em>.—One objective of systematics is to recognize species in a manner that minimizes the disparity between species as real entities in nature and species as a Linnaean category. Reconciliation requires a conceptualization of species consistent with evolutionary processes that yields predictive delimitation criteria. Here we review the unified species concept (USC) and its associated delimitation criteria as a prelude to revising the taxonomy of Cutthroat Trout <em>Oncorhynchus clarkii</em>. Additionally, in the context of the conceptualizing species as a separately evolving metapopulation, we briefly review how climate change may have influenced the connectivity and isolation of Cutthroat Trout within and among river basins, with a focus mainly on the Cutthroat Trout of the Southern Rocky Mountains. We summarize evidence based on delimitation criteria that distinguishes Rainbow Trout <em>O. mykiss</em> and Cutthroat Trout, Gila Trout<em> O. gilae </em>and Rainbow Trout, and blue lineage and green lineage Cutthroat Trout from the Southern Rocky Mountains. We advocate adopting the USC as a guide for taxonomic revision of Cutthroat Trout, recommend eliminating subspecies as a valid taxonomic designation, and expect—based on our evaluation of three pairs of species—that the taxonomy of Cutthroat Trout will be revised in ways that elevate some recognized subspecies to species status.

Cutthroat Trout: Evolutionary Biology and Taxonomy

2018 ◽  
Keyword(s):  
Evolutionary Biology ◽  
Species Concept ◽  
Management Strategies ◽  
Cutthroat Trout ◽  
Ecological Processes ◽  
Oncorhynchus Clarkii ◽  
Voucher Specimens ◽  
Captive Propagation ◽  
Analytical Tools

<em>Abstract</em>.—The broad distribution and regional variation of Cutthroat Trout <em>Oncorhynchus clarkii </em>across western North America has led to considerable interest in the different forms from both scientific and recreational perspectives. This volume represents an attempt to describe this observed diversity with the most current information available and suggests a revised taxonomy for Cutthroat Trout. However, what is proposed in this volume will be subject to change or refinement as new techniques and analytical tools become available. In particular, remaining uncertainty would benefit from a comparison of all described lineages with a common set of morphological and genetic markers. A range-wide collection of voucher specimens will help to document variation in these characteristics, and we encourage field biologists to prioritize these collections. Future revisions will benefit from agreement on a species concept and explicitly state the assumptions of the chosen species concept. We encourage collaboration between managers and taxonomists to accurately delineate units of conservation that can be used by decision makers tasked with ensuring the long-term persistence of Cutthroat Trout lineages. The proposed taxonomic revisions herein validate many of the ongoing management strategies to conserve Cutthroat Trout, but we advise additional consideration of life-history diversity as an attainable management target. For long-term persistence of all Cutthroat Trout, maintaining and expanding the availability of high quality, well-connected stream and lake habitats will be a necessary first step to achieving desired conservation outcomes. Moreover, restoring and protecting ecological processes are key to conserving the diversity found within and among lineages of Cutthroat Trout. In systems where native Cutthroat Trout have been extirpated or suppressed, captive propagation and translocation are two potentially available tools to re-establish or reinvigorate populations. Last, we encourage fisheries managers and taxonomists to embrace the challenges that come with conserving locally unique forms of wide-ranging species like Cutthroat Trout.

Status, Distribution, and Conservation of Native Freshwater Fishes of Western North America

2007 ◽  
Keyword(s):  
New Mexico ◽  
Cutthroat Trout ◽  
Rio Grande ◽  
National Forests ◽  
Santa Fe ◽  
Private Lands ◽  
Indian Reservation ◽  
Oncorhynchus Clarkii ◽  
Fort Apache Indian Reservation ◽  
Central Arizona

ABSTRACT Three native trouts occur in the southwestern United States. The Rio Grande cutthroat trout <em>Oncorhynchus clarkii virginalis</em> persists in New Mexico and southern Colorado on the Santa Fe, Carson, and Rio Grande national forests and private lands. The Gila trout <em>O. gilae</em> and the Apache trout <em>O. gilae apache</em> (also known as <em>O. apache</em>) occur in isolated headwater streams of the Gila and Little Colorado rivers on the Gila and Apache- Sitgreaves national forests and Fort Apache Indian Reservation in southwestern New Mexico and east-central Arizona, respectively. For more than two decades, intensive management has been directed at the Apache, Gila, and Rio Grande cutthroat trouts. Despite the efforts, their decades-long listed status remains unchanged for the Gila and Apache trouts, and the Rio Grande native is under consideration for listing. The objectives of this paper are to review the literature and management activities over the past quarter of a century in order to delineate why recovery and conservation have been so difficult for southwestern trout.

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