Multiscale Genetic Structure of Yellowstone Cutthroat Trout in the Upper Snake River Basin

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 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 × cutthroat hybrid occupancy increased from 23 reaches in the 1980s to 36 reaches in 1999–2000, and then declined back to 23 reaches in 2010–2011. The proportion of reaches occupied by brown trout Salmo trutta and brook trout Salvelinus fontinalis 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, estimates of abundance increased over time for all species of nonnative trout. Population growth rate (λ) was therefore below replacement for Yellowstone cutthroat trout (mean = 0.98) and above replacement for rainbow trout (1.07), brown trout (1.08), and brook trout (1.04), but 90% confidence intervals overlapped unity for all species. However, λ differed statistically from 1.00 within some individual drainages for each species. More pronounced drought conditions in any given year resulted in lower Yellowstone cutthroat trout abundance 1 y later. Our results suggest that over a span of up to 32 y, the distribution and abundance of Yellowstone cutthroat trout in the upper Snake River basin of Idaho appears to be relatively stable, and nonnative trout do not currently appear to be expanding across the basin.

Download Full-text

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

North American Journal of Fisheries Management ◽

10.1080/02755947.2011.640899 ◽

2011 ◽

Vol 31 (6) ◽

pp. 1077-1087 ◽

Cited By ~ 14

Author(s):

Ryan P. Kovach ◽

Lisa A. Eby ◽

Matthew P. Corsi

Keyword(s):

Rainbow Trout ◽

River Basin ◽

Cutthroat Trout ◽

Snake River ◽

Yellowstone Cutthroat Trout

Download Full-text

Hybridization of Snake River Cutthroat in the Lower Gros Ventre River

The UW National Parks Service Research Station Annual Reports ◽

10.13001/uwnpsrc.2006.3665 ◽

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 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.

Download Full-text

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).

Download Full-text

Two Ocean Pass: An Alternative Hypothesis for the Invasion of Yellowstone Lake by Lake Trout, and Implications for Future Invasions

Water ◽

10.3390/w12061629 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1629 ◽

Cited By ~ 1

Author(s):

Todd M. Koel ◽

Colleen R. Detjens ◽

Alexander V. Zale

Keyword(s):

Brook Trout ◽

National Park ◽

Lake Trout ◽

Cutthroat Trout ◽

Snake River ◽

Yellowstone Lake ◽

Yellowstone River ◽

Continental Divide ◽

Nonnative Fish ◽

Yellowstone Cutthroat Trout

Preventing the interbasin transfer of aquatic invasive species is a high priority for natural resource managers. Such transfers can be made by humans or can occur by dispersal through connected waterways. A natural surface water connection between the Atlantic and Pacific drainages in North America exists at Two Ocean Pass south of Yellowstone National Park. Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri used this route to cross the Continental Divide and colonize the Yellowstone River from ancestral sources in the Snake River following glacial recession 14,000 bp. Nonnative lake trout Salvelinus namaycush were stocked into lakes in the Snake River headwaters in 1890 and quickly dispersed downstream. Lake trout were discovered in Yellowstone Lake in 1994 and were assumed to have been illegally introduced. Recently, lake trout have demonstrated their ability to move widely through river systems and invade headwater lakes in Glacier National Park. Our objective was to determine if lake trout and other nonnative fish were present in the connected waters near Two Ocean Pass and could thereby colonize the Yellowstone River basin in the past or future. We used environmental DNA (eDNA), electrofishing, and angling to survey for lake trout and other fishes. Yellowstone cutthroat trout were detected at nearly all sites on both sides of the Continental Divide. Lake trout and invasive brook trout S. fontinalis were detected in Pacific Creek near its confluence with the Snake River. We conclude that invasive movements by lake trout from the Snake River over Two Ocean Pass may have resulted in their colonization of Yellowstone Lake. Moreover, Yellowstone Lake may be vulnerable to additional invasions because several other nonnative fish inhabit the upper Snake River. In the future, eDNA collected across smaller spatial intervals in Pacific Creek during flow conditions more conducive to lake trout movement may provide further insight into the extent of non-native fish invasions in this stream.

Download Full-text