Using an Integrated Population Model to Evaluate Yellowstone Cutthroat Trout Responses to Management Actions

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 fineÂ 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.

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An integrated population model for estimating the relative effects of natural and anthropogenic factors on a threatened population of Pacific trout

10.1101/734996 ◽

2019 ◽

Cited By ~ 1

Author(s):

Mark D. Scheuerell ◽

Casey P. Ruff ◽

Joseph H. Anderson ◽

Eric M. Beamer

Keyword(s):

At Risk ◽

Population Model ◽

Habitat Restoration ◽

Negative Relationship ◽

Anthropogenic Factors ◽

List Type ◽

Population Demographics ◽

Density Dependent ◽

Integrated Population Model ◽

The North

SummaryAssessing the degree to which at-risk species are regulated by density dependent versus density independent factors is often complicated by incomplete or biased information. If not addressed in an appropriate manner, errors in the data can affect estimates of population demographics, which may obfuscate the anticipated response of the population to a specific action.We developed a Bayesian integrated population model that accounts explicitly for interannual variability in the number of reproducing adults and their age structure, harvest, and environmental conditions. We apply the model to 41 years of data for a population of threatened steelhead troutOncorhynchus mykissusing freshwater flows, ocean indices, and releases of hatchery-born conspecifics as covariates.We found compelling evidence that the population is under strong density dependence, despite being well below its historical population size. In the freshwater portion of the lifecycle, we found a negative relationship between productivity (offspring per parent) and peak winter flows, and a positive relationship with summer flows. We also found a negative relationship between productivity and releases of hatchery conspecifics. In the marine portion of the lifecycle, we found a positive correlation between productivity and the North Pacific Gyre Oscillation. Furthermore, harvest rates on wild fish have been sufficiently low to ensure very little risk of overfishing.Synthesis and applications.The evidence for density dependent population regulation, combined with the substantial loss of juvenile rearing habitat in this river basin, suggests that habitat restoration could benefit this population of at-risk steelhead. Our results also imply that hatchery programs for steelhead need to be considered carefully with respect to habitat availability and recovery goals for wild steelhead. If releases of hatchery steelhead have indeed limited the production potential of wild steelhead, there are likely significant tradeoffs between providing harvest opportunities via hatchery steelhead production, and achieving wild steelhead recovery goals.

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Effects of Climate and Biotic Factors on Life History Characteristics and Vital Rates of Yellowstone Cutthroat Trout in Spread Creek, Wyoming

The UW National Parks Service Research Station Annual Reports ◽

10.13001/uwnpsrc.2013.4013 ◽

2013 ◽

Vol 36 ◽

pp. 160-174

Author(s):

Patrick Uthe ◽

Robert Al-Chokhachy

Keyword(s):

Life History ◽

Brook Trout ◽

Cutthroat Trout ◽

Conservation Strategies ◽

Snake River ◽

Vital Rates ◽

Factors Influencing ◽

Yellowstone Cutthroat Trout ◽

Life History Patterns ◽

Diversity Of Life

The Upper Snake River represents one of the largest remaining strongholds of Yellowstone cutthroat across its native range. Understanding the effects of restoration activities and the diversity of life-history patterns and factors influencing such patterns remains paramount for long-term conservation strategies. In 2011, we initiated a project to quantify the success of the removal of a historic barrier on Spread Creek and to evaluate the relative influence of different climate attributes on native Yellowstone cutthroat trout and non-native brook trout behavior and fitness. Our results to date have demonstrated the partial success of the dam removal with large, fluvial Yellowstone cutthroat trout migrating up Spread Creek to spawn, thus reconnecting this population to the greater Snake River metapopulation. Early indications from mark-recapture data demonstrate considerable differences in life-history and demographic patterns across tributaries within the Spread Creek drainage. Our results highlight the diversity of life-history patterns of resident and fluvial Yellowstone cutthroat trout with considerable differences in seasonal and annual growth rates and behavior across populations. Continuing to understand the factors influencing such patterns will provide a template for prioritizing restoration activities in the context of future challenges to conservation (e.g., climate change).

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Greater predation by Double-crested Cormorants on cutthroat versus rainbow trout fingerlings stocked in a Wyoming river

Canadian Journal of Zoology ◽

10.1139/z99-164 ◽

1999 ◽

Vol 77 (12) ◽

pp. 1984-1990 ◽

Cited By ~ 5

Author(s):

James R Lovvorn ◽

Daniel Yule ◽

Clayton E Derby

Keyword(s):

Rainbow Trout ◽

Cutthroat Trout ◽

Phalacrocorax Auritus ◽

Limited Data ◽

Platte River ◽

The North ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Oncorhynchus Clarki Bouvieri ◽

Pelecanus Erythrorhynchos ◽

Yellowstone Cutthroat Trout

We studied the relative vulnerability of Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) versus rainbow trout (Oncorhynchus mykiss) stocked as fingerlings in the North Platte River, Wyoming, to Double-crested Cormorant (Phalacrocorax auritus) predation. Cutthroat fingerlings decreased as a fraction of the population from stocking in late June to electrofishing surveys in the following October and March. In contrast, the fraction of cutthroat fingerlings among tagged fingerlings eaten by cormorants collected on the river was significantly greater than that in the population when originally stocked. More limited data from pellets regurgitated by adult cormorants at a nearby colony and in American White Pelicans (Pelecanus erythrorhynchos) collected on the river showed the same trend toward greater percentages of cutthroat trout being consumed than were present among trout stocked. There were no differences in cormorant predation rates on the Eagle Lake strain of rainbow trout reared under shaded versus partially shaded conditions, or between Auburn and Bar BC strains of Snake River (Yellowstone) cutthroat trout. On the North Platte River, cutthroat trout fingerlings were more susceptible to cormorant predation than rainbow trout of similar size that were stocked simultaneously.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2020-0408 ◽

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.

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Cutthroat Trout: Evolutionary Biology and Taxonomy

Cutthroat Trout: Evolutionary Biology and Taxonomy ◽

10.47886/9781934874509.ch7 ◽

2018 ◽

Author(s):

Joseph P. Brunelli

Keyword(s):

Evolutionary Biology ◽

Cutthroat Trout ◽

Paternal Inheritance ◽

Westslope Cutthroat Trout ◽

Chromosome Marker ◽

Mitochondrial Markers ◽

Coastal Cutthroat Trout ◽

Lahontan Cutthroat Trout ◽

Yellowstone Cutthroat Trout

Abstract.—A Y chromosome marker shared with Rainbow Trout Oncorhynchus mykiss has been sequenced in many Cutthroat Trout O. clarkii subspecies. The marker is found in and inherited through males. It evolves more slowly than the maternally inherited mitochondrial DNA. The marker delineates the four major groups of Cutthroat Trout: the Lahontan Cutthroat Trout O. c. henshawi subspecies complex, the Yellowstone Cutthroat Trout O. c. bouvieri subspecies complex, Westslope Cutthroat Trout O. c. lewisi, and Coastal Cutthroat Trout O. c. clarkii. The paternal inheritance pattern of the Y marker makes it useful for dissecting the origins of fish with mixed ancestries. We describe a case study using both Y and mitochondrial markers in Lahontan Cutthroat Trout subspecies complex trout populations. Our results confirmed Lahontan Cutthroat Trout affinities for the Paiute Cutthroat Trout O. c. seleniris and Willow–Whitehorse Creek Cutthroat Trout. However, we found evidence of a complex ancestry for Guano Creek, Oregon trout, a group that has been proposed by some to be related to the Alvord Cutthroat Trout, a subspecies thought to be extinct.

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