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ARS Home » Northeast Area » Orono, Maine » National Cold Water Marine Aquaculture Center » Research » Publications at this Location » Publication #435116
Research Project: Genetic Improvement of the Eastern Oyster for Aquaculture Production

Location: National Cold Water Marine Aquaculture Center

Title: Long-term genetic outcomes of a mixed-source introduction of westslope cutthroat trout

Author
item BELL, DONOVAN - Fish Wildlife And Parks
item KOVACH, RYAN - Fish Wildlife And Parks
item CAMPBELL, MATTHEW - Idaho Department Of Fish & Game
item Delomas, Thomas
item NELSON, LEE - Fish Wildlife And Parks
item CLANCEY, PATRICK - Fish Wildlife And Parks
item SHEPARD, BRADLEY - Fish Wildlife And Parks
item WILLIAMS, JACOB - Turner Enterprises, Inc
item KRUSE, CARTER - Turner Enterprises, Inc
item WHITELEY, ANDREW - University Of Montana

Submitted to: Canadian Journal of Fisheries and Aquatic Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2026
Publication Date: 7/13/2026
Citation: Bell, D.A., Kovach, R., Campbell, M., Delomas, T.A., Nelson, L., Clancey, P.J., Shepard, B., Williams, J., Kruse, C., Whiteley, A.R. 2026. Long-term genetic outcomes of a mixed-source introduction of westslope cutthroat trout. Canadian Journal of Fisheries and Aquatic Sciences. 83, 1-10. https://doi.org/10.5061/dryad.4qrfj6qrc.
DOI: https://doi.org/10.5061/dryad.4qrfj6qrc

Interpretive Summary: Aquaculture animals are often used to augment wild populations. When breeding animals for the (re)introduction of a species, it is often unclear what the best population is to take founders from. We report here the long term results of introducing hatchery-origin cutthroat trout from multiple sources into the same drainage. We found that fish from sources with higher genetic diversity outperformed sources with lower genetic diversity and the resulting population quickly became mixed ancestry. This study verifies the importance of obtaining founders from genetically diverse populations for (re)introduction of a species.

Technical Abstract: Introductions are an increasingly important conservation tool, but few long-term studies have examined how source population selection influences outcomes. We examined the long-term (approximately 4 generations) genetic outcomes of a large-scale, mixed-source introduction of westslope cutthroat trout in Cherry Creek, Montana. We tested whether source population contribution deviated from random expectations (a proxy for fitness), and whether this correlated with source population characteristics. The two donor stocks with the lowest genetic variation had reduced contributions to the final population, whereas those with the highest genetic variation exceeded random expectations by 145-193%. Source contribution was strongly correlated with genetic variation (R² = 0.6). Nearly every fish in the final study year had mixed ancestry, and mean observed heterozygosity reached its highest recorded level, surpassing any one source. Our results suggest that using multiple sources and sources with higher variation may improve the outcomes of conservation introductions across multiple generations.