US Forest Service Research & Development
Contact Information
  • US Forest Service Research & Development
  • 1400 Independence Ave., SW
  • Washington, D.C. 20250-0003
  • 800-832-1355
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Dan Isaak - Research Fish Biologist

Daniel J. Isaak

Research Fish Biologist
322 East Front Street, Suite 401
United States

Phone: 208-373-4385
Fax: 208-373-4391
Contact Daniel J. Isaak

Current Research

Understanding effects of climate change on stream habitats and fish communities, Development and implementation of basinscale and regional monitoring programs for bull trout and other aquatic organisms. Development and implementation of basinscale and regional stream temperature models and monitoring protocols . Effects of fire and disturbance on streams. Development of bioclimatic models to predict distributions of trout species to climate scenarios at regional and basinscales.

For more information, please see:

The Rangewide Bull Trout eDNA Project

The National Stream Internet

Climate Shield Cold-Water Refuge Streams for Native Trout

Climate Change, Crowd-Sourcing, and Conserving Aquatic Biotas in the Rocky Mountains This Century

Adaptation for Wildland Aquatic Resources - Science Briefing

Bull Trout and Climate Change - Science Briefing

Bull Trout Monitoring - Science Briefing

Application of a Spatially Explicit Decision Framework for Fish Conservation - Science Briefing

Climate Change and Rocky Mountain Native Trout - Science Briefing

Climate Change and Wildfires: Effects on Stream Temperatures and Thermal Habitat - Science Briefing

A National Stream Internet - Science Briefing

NorWeST: A Regional Stream Temperature Database and Modeled Climate Scenarios – Science Briefing

Pilot Watershed Vulnerability Assessment Project - Science Briefing

Spatial Statistical Modeling Tools for Stream Networks - Science Briefing

Species Distribution Uncertainty - Science Briefing

Stream Isotherm Shifts From Climate Change - Briefing Paper

Stream Temperature Modeling and Monitoring - Science Briefing

Using Underwater Epoxy To Install Temperature Sensors - Science Briefing

Research Interests

My primary research interest is in understanding how climate change, disturbance, and biophysical interactions across spatial and temporal scales affect population dynamics of aquatic organisms and their habitats in mountain streams.

The National Stream Internet - The NSI is a network of people, data, and analytical techniques that interact synergistically to create information about streams. This website is a hub designed to connect users with software, data, and tools for creating that information. As better information is developed, it should enable stronger science, management, and conservation as pertains to stream ecosystems.

Cold Water Climate Shield - The Climate Shield website hosts geospatial data and related information that describes specific locations of cold-water refuge streams for native Cutthroat Trout and Bull Trout across the northwestern U.S. Forecasts about the locations of refugia could enable the protection of key watersheds, be used to rally support among multiple stakeholders, and provide a foundation for planning climate-smart conservation networks that improve the odds of preserving native trout populations through the 21st century.

Climate- Aquatics Blog: This website archives blogs periodically written by the scientist that describe research pertaining to climate change effects on aquatic resources.

Stream Temperature Modeling and Monitoring Website: This website acts as central repository for information pertaining to monitoring and modeling of stream temperatures that the scientist and his collaborators develop.

SSN & STARS: Tools for Spatial Statistical Modeling on Stream Networks: This website hosts freeware statistical software and GIS tools for implementing a new class of spatial statistical models applicable to data measured on stream networks.

NorWest Stream Temperature- Regional Database and Model: This website hosts a comprehensive interagency stream temperature database and high resolution climate scenarios for the Northwest U.S.

Please click here if interested in following on Twitter.

RMRS Scientist Profile Video (YouTube) - Dr. Dan Isaak talks about building the publically-accessible NorWeST stream temperature database and Its applications for identifying climate refugia for cold-water fish.

Past Research

Assessing spatial and temporal variation in demographic and genetic characteristics of Chinook salmon populations in central Idaho. Landscape ecology and relationships between trout abundance and distributions relative to landscape characteristics. Radio telemetry and distributional assessments of northern pikeminnow in the Lower Snake River.

Please see also:

2011 Climate- Aquatics Workshop

2009 Western Watersheds and Climate Change Workshop

2008 Bull Trout and Climate Change Symposium

Why This Research is Important

Many natural resources are at risk from human development of natural landscapes and the effects of climate change. My research attempts to provide better understanding and predictive models of stream ecosystems so that managers can respond proactively and more effectively to these threats.


  • South Dakota State University, B.S. Wildlife and Fisheries Sciences 1991
  • University of Idaho, M.S. Fisheries Resources 1994
  • University of Wyoming, Ph.D. Zoology and Physiology 2001

Featured Publications & Products


Citations of non US Forest Service Publications

  • Chandler, G.L.; Wollrab, S.P.; Horan, D. L.; Nagel, D. E.; Parkes, S.L.; Isaak, D.J.; Horan, D.L; Wenger, S.J.; Peterson, E.E.; Ver Hoef, J.M.; Hostetler, S.W.; Luce, C.H.; Dunham, J.B.; Kershner, J.L.; Roper, B.B. 2016. NorWeST stream temperature data summaries for the western U.S. Fort Collins, CO: Forest Service Research Data Archive.

  • Isaak, D.J.; Wenger, S.J.; Peterson, E.E.; Ver Hoef, J.M.; Hostetler, S.W.; Luce, C.H.; Dunham, J.B.; Kershner, J.L.; Roper, B.B.; Nagel, D.E.; Chandler, G.L.; Wollrab, S.P.; Parkes, S.L.; Horan, D.L. 2016. NorWeST modeled summer stream temperature scenarios for the western U.S. Fort Collins, CO: Forest Service Research Data Archive.

  • Young, Michael K.; Isaak, Daniel J.; McKelvey, Kevin S.; Schwartz, Michael K.; Carim, Kellie J.; Fredenberg, Wade; Wilcox, Taylor M.; Franklin, Thomas W.; Chandler, Gwynne L.; Nagel, David E.; Parkes-Payne, Sharon L.; Horan, Dona L.; Wollrab, Sherry P. 2017. Species occurrence data from the Range-Wide Bull Trout eDNA Project. Fort Collins, CO: Forest Service Research Data Archive.

  • Schwartz, M. K., Young, M.K., McKelvey, K.S., Isaak, D.J., Nagel, D.E., Franklin, T.W., Greaves, S.E., Dysthe, J.C., Chandler, G.L., Wollrab, S.P., Carim, K.J., Wilcox, T.M., Parkes-Payne, S.L., Horan, D.L. 2018. Species occurrence data from the Aquatic eDNAtlas database. Fort Collins, CO: Forest Service Research Data Archive. DOI Pending.

Research Highlights


Detection and Range Delineation of Bull Trout Using Environmental DNA

The bull trout is listed as an endanged species that relies on cold stream environments across the Northwest and is expected to decline with cli ...


Headwater Streams are Resistant to Trout Hybridization

Hybridization between native and introduced species is noted as an important player in the decline of native species. The potential for hybridiz ...


Mapping Climate Refugia to Preserve Cold-water Biodiversity Using Crowd-sourced Databases

Climate change is rapidly altering stream and river environments across the western U.S. and may threaten the long-term persistence of populatio ...


Monitoring the impact of changing climate on western rivers and cold water species

While coldwater fish such as salmon and trout can adjust to slightly warmer-than-normal temperatures for short periods, abnormally high temperat ...


New Class of Statistical Model Developed for Stream Networks

Researchers and their cooperators developed a new class of statistical model for stream networks that applies to most types of stream data and p ...


The Cold Water Climate Shield: Prioritizing High-value Aquatic Resources

Native trout are culturally and ecologically important, but climate change is likely to shrink the cold-water environments they require. Much ca ...


The eDNAtlas project: A national map of aquatic biodiversity

eDNA sampling provides a low-cost & sensitive method for determining which species occur in water bodies. Rapid adoption of eDNA sampling by man ...


Last updated on : 10/01/2021