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Project ID: 2005MT71B

Title: STUDENT FELLOWSHIP: Factors that influence displacement of native cutthroat trout by nonnative brook trout

Project Type: Research

Focus Categories: Ecology, Nutrients, Hydrology

Keywords: trout, displacement

Start Date: 03/15/2005

End Date: 06/30/2006

Federal Funds: $1,500

Non-Federal Matching Funds: $0

Congressional District: At Large

Principal Investigators:
Alexander Zale

Brad Shepard
Montana State University


The Problem: Declines in the abundance, distribution, and genetic diversity of westslope cutthroat trout Oncorhynchus clarki lewisi throughout their native range, especially within the upper Missouri River basin in the Northern Rocky Mountains, have prompted fisheries managers to identify mechanisms responsible for population declines, and develop effective conservation and recovery programs (Allendorf and Leary 1988; Liknes and Graham 1988; Behnke 1992; McIntyre and Rieman 1995; Shepard et al. 1997). Factors associated with these declines include introductions of nonnative fishes, habitat changes, and over-exploitation (Hanzel 1959; Liknes and Graham 1988; Behnke 1992; McIntyre and Rieman 1995). Many habitats previously occupied by WCT in the Northern Rocky Mountains now contain populations of other nonnative trout, particularly brook trout Salvelinus fontinalis (Behnke 1992; McIntyre and Rieman 1995), indicating that nonnative trout may replace or displace WCT (MacPhee 1966; Griffith 1972; Behnke 1979; Liknes and Graham 1988; Griffith 1988; Dunham et al. 2003); however, little information exists regarding the mechanisms responsible for displacement of cutthroat trout by brook trout. Conservation of cutthroat trout requires maintaining healthy watersheds, as cutthroat trout need cold, clean water to persist. My research will focus on how watershed conditions influence the persistence of cutthroat trout, especially on how these conditions influence the displacement of cutthroat trout by nonnative brook trout.

Progress/Completion Report PDF

U.S. Department of the Interior, U.S. Geological Survey
Maintained by: John Schefter
Last Updated: Wednesday June 22, 2005 3:31 PM
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