Cooperative Fish and Wildlife Research Units Program: Utah
Education, Research and Technical Assistance for Managing Our Natural Resources

Utah Project

Long-Term Logan River Trout Viability Study and Monitoring

January 2001 - September 2021


Participating Agencies

  • Utah Division of Wildlife Resources

While the importance of reducing the impacts of non-native species is increasingly recognized in conservation, the feasibility of such actions is highly dependent upon several key uncertainties including the stage of invasion, the size of the ecosystem being restored, and the magnitude of the restoration activity. Here, we present the results of a multi-year, non-native brown trout (Salmo trutta) removal and native Bonneville cutthroat trout (Oncorhynchus clarkii utah) recovery in a small tributary in the Intermountain West, USA. We monitored trout populations for seven years prior to the onset of eradication efforts, which included two years of mechanical removal followed by two years of chemical treatment. Cutthroat trout populations were then seeded with low numbers of both eggs and juvenile trout. We monitored population demographics and estimated population growth rates and carrying capacities for both populations from long-term depletion estimate data, assuming logistic growth. Prior to eradication, brown trout populations fluctuated around their carrying capacity. Following brown trout eradication and initial seeding efforts, cutthroat trout populations have demonstrated exponential growth. Within five years, cutthroat trout have approached their estimated carrying capacity. Population projections suggest a 50% probability that cutthroat trout are currently at or above 90% of their carrying capacity, and that there is an 80 to 90% probability they will be at or above 90% of their carrying capacity within 10 years. Additionally, at least four age-classes are present including adults large enough to satisfy angling demand. This project is a collaboration of biologists, academics, and anglers and includes the Utah Division of Wildlife Resources , U.S. Forest Service Rocky Mountain Research Station, the local chapter of Trout Unlimited – Cache Anglers, and the Ecology Center at Utah State University. These results demonstrate native trout species have substantial capacity to rapidly recover following the removal of invasive species in otherwise minimally altered habitats. While these locations are likely limited in extent individually, collectively they may serve as source populations for larger connected systems. In such cases, these source populations may provide additional conservation potential through biotic resistance.

Research Publications Publication Date
Wood, J. and P. Budy. 2009. An investigation of the early life-history and potential influences on invasion success of exotic of brown trout (Salmo trutta). Transactions of the American Fisheries Society 138:756-767. May 2009
Murphy, B., T. Walsworth, P. Belmont, M.M. Conner, and P. Budy. 2020. Dynamic Habitat Disturbance and Ecological Response (DyHDER)-PVA: modeling fish population dynamics in response to landscape disturbance. Ecosphere 11(1):e03023. 10.1002/ecs2.
3023. USGS FSP IP-110023.
January 2020
McIntosh, A., P.A. McHugh, and P. Budy. 2011. Brown Trout, Chapter 24, In: Handbook of Global Freshwater Invasive Species (a summary of the current state of knowledge of 30 of the most notable global invasive freshwater species). Invited BOOK Chapter. ( October 2011
McHugh, P., and P. Budy. 2006. Experimental effects of nonnative brown trout on the individual- and population-level performance of native cutthroat trout. Transactions of the American Fisheries Society 135:1441-1455. November 2006
Hansen, M., P. Budy , C. Guy, and T. McMahon. 2019. Trout as Native and Invasive Species: a Management Paradox. Invited Chapter 819 in: Diversity and Status of Trouts and Chars of the World. Editors: J.L. Kershner, J. E. Williams, R. E. Gresswell. Transactions of the American Fisheries Society. Symposium Book. USGS FSP: IP-095921. May 2019
Hansen, E., and P. Budy. 2011. The potential of passive stream restoration to improve ecosystem health and minimize the impact of fish disease: a short-term assessment. Journal of the North American Benthological Society 30:573-588. June 2011
De la Hoz Franco, E. A., and P. Budy. Accepted. Effects of biotic and abiotic factors on the distribution of trout and salmon along a longitudinal stream gradient. Environmental Biology of Fishes 72:379-391. July 2004
De la Hoz Franco, E. A., and P. Budy. 2004. Linking Environmental Heterogeneity to the Distribution and Prevalence of Myxobolus cerebralis: A Comparison Across Sites in a Northern, Utah Transactions of the American Fisheries Society 133:1165-1178. April 2004
Budy, P., T. Walsworth, G.P. Thiede, P.D. Thompson, M.D. McKell, P.B. Holden, P.D., Chase, W.c. Saunders. 2021. Remarkably rapid recovery of native trout following removal of a dominant non-native trout sub-population: evidence of resilience and conservation potential. Conservation Biology: Conservation Practice and Policy 2021;3:e325. | Abstract January 2021
Budy, P., K.B. Rogers, Y. Kanno, B. Penaluna, N.H. Hitt. J. Dunham, C. Mellison, and W.L. Somer. 2019 Distribution and Status of Trouts and Chars in North America. Invited Chapter 8 in: Diversity and Status of Trouts and Chars of the World. Editors: J.L. Kershner, J. E. Williams, R. E. Gresswell. American Fisheries Society. Symposium Book. USGS FSP: IP-088494. | Abstract May 2019
Budy, P., G. P. Thiede, P. McHugh, E. S. Hansen, and J. Wood. 2008. Exploring the relative influence of biotic interactions and environmental conditions on the abundance and distribution of exotic brown trout (Salmo trutta) in a high mountain stream. Ecology of Freshwater Fish 17:554-556. June 2008
Budy, P. and J. Gaeta. 2018. Brown trout as an invader: A Synthesis of Problems and Perspectives in Western North America. Invited Chapter 12.1 in: The Brown Trout Salmo trutta L.: A primer on a paradigmatic species. Editors: Javier Lobón-Cerviá & Nuria Sanz Ball.llosera. Wiley. USGS FSP: IP-058204 | Abstract February 2018
Bennet, S., B. Roper, R. Al-Chokhachy, and P. Budy. 2014. Annual Variation of Spawning Cutthroat Trout in a Small Western USA Stream: A Case Study with Implications for the Conservation of Potamodromous Trout Life History Diversity. North American Journal of Fisheries Management 34:1033-1046. USGS FSP:IP-050825. | Abstract January 2014
Theses and Dissertations Publication Date
Wood, Jeremiah. 2008. An investigation of the early life-history of exotic brown trout (Salmo trutta) and potential influences on invasion success. MS Thesis. Utah State University, 48 pages. July 2008
Seidel, Sara. 2009. Spawning ecology and early-life history of imperiled, endemic cutthroat trout. MS Thesis. Utah State University, 59 pages. June 2009
Mohn, Harrison. 2016. Improving management and conservation practices of Bonneville cutthroat trout (Onchorhynchus clarkii Utah) through an evaluation of movement and spatial population structure. Co-advised with Brett Roper. MS Thesis. Ecology. Utah State University. May 2016
Meredith, Christy. 2012. Effects of a changing physical template on the longitudinal distribution of brown trout in a mountain stream: implications for brown trout invasion success. PhD. Ecology, Utah State University. May 2012