Assessing Thermal Sensitivities of Salmon Habitats in the Cook Inlet, Copper River, and Prince William Sound Watersheds

Salmonid Restoration Planning and Assessments

Salmonid Habitat Assessment / Inventory
Project IDAK51012
Recovery Domains -
Start Date03/01/2019
End Date03/31/2022
Last Edited07/13/2022
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This project characterized stream temperature regimes in the Cook Inlet, Copper River, and Prince William Sound regions. We aggregated 1,548 summertime stream temperature time series from 355 monitoring locations across southwestern and southcentral Alaska and calculated a suite of metrics related to the magnitude, frequency, duration, timing, and variability of stream temperatures. We categorized streams into one of six different thermal regimes. A comparison of stream thermal regimes among regions showed that cold habitats with later timing of maximum temperatures were most common in all regions, cold stable habitats were more common in the Copper River and Prince William Sound regions, and all regions included all six thermal regimes described in our classification.

We also calculated stream thermal sensitivity (¿) across monitoring sites to describe how closely stream temperatures track air temperatures. Estimated ¿ was highest in the Cook Inlet and Kodiak regions, followed by Bristol Bay and Copper River, and was lowest in Prince William Sound. We modeled variation in ¿ using geomorphic, hydrologic, climatic, and landcover covariates. The model was used to map thermal sensitivities across 966 salmon streams for high and low scenarios of spring snowpack and summer precipitation. Thermal sensitivities decreased under higher summertime precipitation and changed minimally between years with low and high snowpack. The strongest control on ¿ was watershed slope. Streams draining steeper watersheds had lower ¿, which may be due to snowmelt contributions later in the summer period, shorter water residence times, and deeper flowpaths that experience less solar radiation. Chum and pink salmon habitats had the lowest ¿, followed by spawning habitats. Rearing habitats and Chinook, coho, and sockeye salmon habitats all had higher ¿. In a warming future, salmon may need to balance physical habitat preferences for low gradient systems with adaptations for cold water.

Project Benefit    

Understanding climate vulnerability of salmon in Alaska will require a better understanding of salmon habitat sensitivities to changes in temperature. The tool developed by this project can be used to identify populations and habitats at risk, develop monitoring and evaluation programs, inform future research and conservation needs, and prepare adaptation strategies in response to or in anticipation of change. This will provide land managers with a vision of the magnitude of change expected and a framework for prioritizing on-the ground adaptation strategies in relation to ecosystem and community resilience.


Metric Completed Originally

Funding Details

Report Total:$350,678

Project Map



  • Worksite Identifier: 45126660
  • Start Date:
  • End Date:
Area Description

No Area Description data was found for this worksite.

Location Information

  • Basin: Susitna River
  • Subbasin:
  • Watershed:
  • Subwatershed:
  • State: Alaska
  • Recovery Domain:
  • Latitude: 61.74
  • Longitude: -150.32


  • Un-Named ESU Sockeye
  • Un-Named ESU Chinook
  • Un-Named ESU Chum
  • Un-Named ESU Coho
  • Un-Named ESU Pink




  • B.0 Salmonid Restoration Planning and AssessmentsY (Y/N)
    •      . . B.0.a Planning And Assessment Funding 350,678.00
    •      . . B.0.b.1 Area Encompassed 26,425,646.0
    •      . . B.0.b.2 Stream Miles Affected 966.00
    •      . . B.2 Salmonid Habitat Assessment / InventoryY (Y/N)
      •      . . . . B.2.a Habitat Assessment Funding 350,678.00
      •      . . . . B.2.b.1 Watershed AssessmentY (Y/N)
        •      . . . . . . B.2.b.2
          Name of document(s)
          Thermal sensitivity maps and geodatabase for salmon streams and watersheds in the Cook Inlet, Copper River, and Prince William Sound regions (