Skip to main content
Article
Resilient and Rapid Recovery of Native Trout After Removal of a Non-Native Trout
Conservation Science and Practice
  • Phaedra E. Budy, Utah State University
  • Timothy Walsworth, Utah State University
  • Gary P. Thiede, Utah State University
  • Paul D. Thompson, Utah Department of Natural Resources
  • Matthew D. McKell, Utah Division of Wildlife Resources
  • Paul B. Holden, Trout Unlimited
  • Paul D. Chase, U. S. Department of Agriculture
  • W. Carl Saunders, Utah State University
Document Type
Article
Publisher
John Wiley & Sons, Inc.
Publication Date
12-4-2020
Keywords
  • carrying capacity,
  • eradication,
  • fish biomass,
  • invasion,
  • mechanical removal,
  • population growth
Disciplines
Creative Commons License
Creative Commons Attribution 4.0
Abstract

While the importance of reducing impacts of non-native species is increasingly recognized in conservation, the feasibility of such actions is highly dependent upon several key uncertainties including stage of invasion, size of the ecosystem being restored, and magnitude of the restoration activity. Here, we present results of a multi-year, non-native brown trout (Salmo trutta) removal and native Bonneville cutthroat trout (Oncorhynchus clarkii utah) response to this removal in a small tributary in the Intermountain West, United States. We monitored trout for 10 years prior to the onset of eradication efforts, which included 2 years of mechanical removal followed by 2 years of chemical treatment. Cutthroat trout were then seeded with low numbers of both eggs and juvenile trout. We monitored demographics and estimated population growth rates and carrying capacities for cutthroat trout from long-term depletion estimate data, assuming logistic population growth. Following brown trout eradication and initial seeding efforts, cutthroat trout in this tributary have responded rapidly and have approached their estimated carrying capacity within 6 years. Population projections suggest a 95% probability that cutthroat trout will be at or above 90% of their carrying capacity within 10 years of the eradication of brown trout. Additionally, at least four age-classes are present including adults large enough to satisfy angling demand. These results demonstrate native trout species have substantial capacity to rapidly recover following removal of invasive species in otherwise minimally altered habitats. While tributaries such as like this study location are likely limited in extent individually, collectively they may serve such as source populations for larger connected systems. In such cases, these source populations may provide additional conservation potential through biotic resistance.

Author ORCID Identifier

Phaedra Budy https://orcid.org/0000-0002-9918-1678

Matthew McKell https://orcid.org/0000-0001-5200-612X

Citation Information
Budy PE, Walsworth T, Thiede GP, et al. Resilient and rapid recovery of native trout after removal of a non-native trout. Conservation Science and Practice. 2021;3:e325. https://doi.org/10.1111/csp2.325