Columbia River Fisheries Program Office
Pacific Region
 

Native Trout Program - Lewis River and White Salmon River Bull Trout: Patches, Occupancy and Distribution

The objective of this project is to describe bull trout patches in the Lewis River and White Salmon River subbasins, Washington, (following Dunham and Rieman 1999, as modified in RMEG 2008). The purpose is to ascertain the utility of this approach for providing guidance in determining potential bull trout distribution in subbasins with limited existing knowledge of the status of this species or information gathered from on-the-ground sampling efforts. Implementation of this project utilizes maximum annual stream temperature, stream size and catchment area as filters for determining potential bull trout habitat in the Lewis River subbasin. Many other factors identified by Dunham and Rieman (1999) may also influence bull trout distribution (e.g., connectivity, stream gradient, geology, hydrologic regimes, presence of nonnative species, road density, solar radiation). However, maximum annual stream temperature (and the corresponding elevation) effectively dictates the range of this species (Rieman and McIntyre 1995) and patch size (catchment area) may be the most important factor determining bull trout occurrence (Dunham and Rieman 1999). Utilizing these three filters provides the opportunity to evaluate a tool using information that most managers can readily acquire.
Overview of Lewis study areaMaximum annual stream temperature can be determined from any stream temperature monitoring efforts occurring in a subbasin through the summer months.  This type of data can be linked to a location, and subsequently to an elevation.  Gathering this information from state and federal agencies, academic institutions, and other reliable sources can go a long way toward building a useful dataset to build temperature:elevation relationships within a subbasin.  Should this information not be readily available or the resulting dataset be insufficient to build temperature:elevation relationships due to large data gaps, it may be possible to acquire this information from a similar subbasin proximate in geographic location.

 

References

Dunham, J.B., and B.E. Rieman. 1999. Metapopulation structure of bull trout: influences of physical, biotic, and geometrical landscape characteristics. Ecological Applications 9:642-655.

Rieman, B.E., and J.D. McIntyre. 1995. Occurrence of bull trout in naturally fragmented habitat patches of varied size. Transactions of the American Fisheries Society 124:285-296.

Reports

Hudson, J.M., J.R. Cook, B.P. Silver, and T.A. Whitesel. 2010. Lewis River Bull Trout Recovery Monitoring and Evaluation: Patches, Occupancy and Distribution. 2006-2007 Progress Report. U.S. Fish and Wildlife Service, Columbia River Fisheries Program Office, Vancouver, Washington. (pdf 1.39mb)

Silver, B., J. Cook, J.M. Hudson, and T.A. Whitesel. 2009. White Salmon River Bull Trout: Patches, Occupancy and Distribution. 2007 Progress Report.

Silver, B., J. Cook, J.M. Hudson, and T.A. Whitesel. 2009. White Salmon River Bull Trout: Patches, Occupancy and Distribution. 2008 Progress Report. (pdf 1.8mb)

Silver, B.P., J.R. Cook, J.M. Hudson and T.A. Whitesel. 2010. Lewis River Bull Trout Recovery Monitoring and Evaluation: Patches, Occupancy and Distribution. 2008 Progress Report

Silver, B., J. Cook, J.M. Hudson, and T.A. Whitesel. 2010. White Salmon River Bull Trout: Patches, Occupancy and Distribution. 2009 Progress Report.(1.4mb)

Silver, B., J.M. Hudson, and T.A. Whitesel. 2011. White Salmon River Bull Trout: Patches, Occupancy and Distribution. 2010 Progress Report. (1.5mb)

Last updated: December 7, 2012
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