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Temporal genetic monitoring of hybridization between native westslope cutthroat trout and introduced rainbow trout in the Stehekin River, Washington

Northwest Science

By:
and
DOI: 10.3955/046.086.0305

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Abstract

Introgressive hybridization with introduced rainbow trout (RBT) (Oncorhynchus mykiss) has led to the loss of native cutthroat trout species (O. clarkii) throughout their range, creating conservation concerns. Monitoring temporal hybridization trends provides resource managers with a tool for determining population status and information for establishing conservation goals for native cutthroat trout. In this study, we re-sampled six locations in 2010 within the Stehekin River watershed, North Cascades National Park, which were originally sampled between 1999 and 2003. We used genetic markers to monitor changes in hybridization levels between sampling periods in the native westslope cutthroat trout (WCT) (O. c. lewisi) stemming from past RBT introductions. Additionally, two new locations from the lower Stehekin drainage were added to the baseline data. We found that the frequency of WCT, RBT, and their hybrids was not significantly different between monitoring periods, but that RBT allele frequencies decreased in two locations and increased in one location. We also found a consistent, substantial reduction in the frequency of RBT alleles over the monitoring period in the Stehekin River upstream of Bridge Creek (SR3) compared to the Stehekin River downstream of Bridge Creek (SR1 -2) and within lower Bridge Creek (BR1) although these three locations are confined to a small geographic area (approximately 5 km). Ecological and/or evolutionary processes likely restrict the dispersal of RBT alleles in the Stehekin River upstream of Bridge Creek.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Temporal genetic monitoring of hybridization between native westslope cutthroat trout and introduced rainbow trout in the Stehekin River, Washington
Series title:
Northwest Science
DOI:
10.3955/046.086.0305
Volume
86
Issue:
3
Year Published:
2012
Language:
English
Publisher:
Northwest Scientific Association
Contributing office(s):
Western Fisheries Research Center
Description:
14 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Northwest Science
First page:
198
Last page:
211
Country:
United States
State:
Washington