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Individual Highlight

Detection and Range Delineation of Bull Trout Using Environmental DNA

Photo of Modeled bull trout habitat in western Montana and northern Idaho. Color coding indicates the estimated likelihood of a stream providing spawning and rearing habitat for bull trout.  USDA Forest ServiceModeled bull trout habitat in western Montana and northern Idaho. Color coding indicates the estimated likelihood of a stream providing spawning and rearing habitat for bull trout. USDA Forest ServiceSnapshot : The bull trout is listed as an endanged species that relies on cold stream environments across the Northwest and is expected to decline with climate change. Resource managers from dozens of agencies are charged with maintaining bull trout in thousands of streams, but monitoring this species is difficult. Environmental DNA (eDNA) is much faster, easier, and more sensitive than traditional fish sampling methods and provides an opportunity to better delineate the range of these species.

Principal Investigators(s) :
McKelvey, Kevin S. Young, Michael K.
Isaak, Daniel J.  
Research Location : Western United States
Research Station : Rocky Mountain Research Station (RMRS)
Year : 2015
Highlight ID : 836


Bull trout are a critical component of aquatic community assemblages, and a focal species for the Great Northern Landscape Conservation Cooperative in all four ecotypic areas: the Columbia Basin, Rocky Mountains, Sagebrush Steppe, and Cascadia. This species is listed as an endangered species and occurs at low densities within thousands of streams designated as critical habitat across the region. Mounting evidence shows that the distribution of bull trout within individuals streams has been contracting in association with climate change; some historically occupied habitats may no longer support populations. Because of the difficulty and expense of sampling bull trout, current information about the species distribution is imprecise and many streams have been sampled infrequently or not at all. To reduce uncertainties (and regulatory gridlock) associated with bull trout, Forest Service scientists recently developed and published the Climate Shield Habitat Occupancy Model, which usesNorWeST temperature information and other environmental covariates to accurately predict the probability of bull trout (and cutthroat trout) presence across the Columbia Basin.. The fish and temperature data used to develop the NorWeST and Climate Shield databases and models were “crowd-sourced.” That approach was particularly powerful because it engaged hundreds of biologists working for dozens of agencies and leveraged their raw data to develop databases worth more than $10,000,000. Building on those efforts, the scientists plan to conduct a precise, up-to-date, range-wide bull trout status assessment through the use of the above described crowd-sourcing, digital media, and new genomic techniques that are revolutionizing the cost-effectiveness of broad-scale species sampling.

Among the array of genomic techniques now available, environmental DNA (eDNA) has emerged as a powerful method for determining the occurrence of many species reliably and inexpensively. The method involves collecting DNA shed by organisms (i.e., environmental DNA) by pumping water through a filter. The scientists have also developed a field-proven eDNA sampling protocol that requires only 15 minutes of effort by a single person to collect a sample.

For bull trout, initial studies with eDNA have been directed at precisely delineating their distribution within select watersheds, as well as confirming their absence from potential habitats and discovering previously unknown populations.Samples collected to evaluate bull trout distributions can be used to evaluate many other species with no additional field costs and can serve as a multi-species baseline for future biodiversity assessments.

Forest Service Partners

External Partners

  • Aubree Benson, Jon Hanson, Shane Hendrickson, and Traci Sylte, USFS Lolo NF
  • Brenda Mitchell, USFS Sawtooth NF
  • Casey Watson, USFS Boise NF
  • Dan Duffield, Lee Jacobson, and Cynthia Tait, USFS Intermountain Region
  • George Liknes, USFS Helena NF
  • Jim Brammer, USFS Beaverhead-Deer Lodge NF
  • John Chatel, USFS Pacific Northwest Region
  • Lisa Howden and Dan Scaife, USFS Idaho Panhandle NF
  • Thomas Cameron, Brian Riggers, and Scott Spaulding, USFS Northern Region
  • Amy Haak, Trout Unlimited
  • Angelo Vitale, Coeur d'Alene Tribes
  • Bob Rose, Yakima Nation
  • Bruce Rieman, Clearwater Resource Council
  • Dan Brewer and Erin Britton Kuttel, U.S. Fish and Wildlife Service
  • David Lawrence, National Fish and Wildlife Foundation
  • Dimitri Vigergar, Bureau of Reclamation
  • Gary Frank, Montana Department of Natural Resources Conservation
  • Kirk Krueger, Washington Department of Fish and Wildlife
  • Ladd Knotek, Ryan Kreiner, Brad Liermann, Ron Pierce, and Pat Saffel, Montana Fish, Wildlife & Parks
  • Rick Wilkison, Idaho Power Company
  • Steve Kloetzel, The Nature Conservancy
  • Tim Copeland, Matt Corsi, Joe Dupont, Jim Fredericks, and Kevin Meyer, Idaho Department of Fish and Game
  • Will McDowell, Clark Fork Coalition