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Population genetics reveals bidirectional fish movement across the Continental Divide via an interbasin water transfer

June 22, 2022

Interbasin water transfers are becoming an increasingly common tool to satisfy municipal and agricultural water demand, but their impacts on movement and gene flow of aquatic organisms are poorly understood. The Grand Ditch is an interbasin water transfer that diverts water from tributaries of the upper Colorado River on the west side of the Continental Divide to the upper Cache la Poudre River on the east side of the Continental Divide. We used single nucleotide polymorphisms to characterize population genetic structure in cutthroat trout (Oncorhynchus clarkii) and determine if fish utilize the Grand Ditch as a movement corridor. Samples were collected from two sites on the west side and three sites on the east side of the Continental Divide. We identified two or three genetic clusters, and relative migration rates and spatial distributions of admixed individuals indicated that the Grand Ditch facilitated bidirectional fish movement across the Continental Divide, a major biogeographic barrier. Previous studies have demonstrated ecological impacts of interbasin water transfers, but our study is one of the first to use genetics to understand how interbasin water transfers affect connectivity between previously isolated watersheds. We also discuss implications on native trout management and balancing water demand and biodiversity conservation.

Publication Year 2022
Title Population genetics reveals bidirectional fish movement across the Continental Divide via an interbasin water transfer
DOI 10.1007/s10592-022-01455-5
Authors Audrey Harris, Sara J. Oyler-McCance, Jennifer A. Fike, Matthew P Fairchild, Christopher M Kennedy, Harry J Crockett, Dana L. Winkelman, Yoichiro Kanno
Publication Type Article
Publication Subtype Journal Article
Series Title Conservation Genetics
Index ID 70238603
Record Source USGS Publications Warehouse
USGS Organization Coop Res Unit Seattle; Fort Collins Science Center
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