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Assessing the impact of stocking northern-origin hatchery brook trout on the genetics of wild populations in North Carolina

Conservation Genetics

By:
ORCID iD , , ORCID iD , and
https://doi.org/10.1007/s10592-017-1037-4

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Abstract

The release of hatchery-origin fish into streams with endemics can degrade the genetics of wild populations if interbreeding occurs. Starting in the 1800s, brook trout descendent from wild populations in the northeastern United States were stocked from hatcheries into streams across broad areas of North America to create and enhance fishery resources. Across the southeastern United States, many millions of hatchery-origin brook trout have been released into hundreds of streams, but the extent of introgression with native populations is not well resolved despite large phylogeographic distances between these groups. We used three assessment approaches based on 12 microsatellite loci to examine the extent of hatchery introgression in 406 wild brook trout populations in North Carolina. We found high levels of differentiation among most collections (mean FST = 0.718), and among most wild collections and hatchery strains (mean FST = 0.732). Our assessment of hatchery introgression was consistent across the three metrics, and indicated that most wild populations have not been strongly influenced by supplemental stocking. However, a small proportion of wild populations in North Carolina appear to have been strongly influenced by stocked conspecifics, or in some cases, may have been founded entirely by hatchery lineages. In addition, we found significant differences in the apparent extent of hatchery introgression among major watersheds, with the Savannah River being the most strongly impacted. Conversely, populations in the Pee Dee River watershed showed little to no evidence of hatchery introgression. Our study represents the first large-scale effort to quantify the extent of hatchery introgression across brook trout populations in the southern Appalachians using highly polymorphic microsatellite markers.

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Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Assessing the impact of stocking northern-origin hatchery brook trout on the genetics of wild populations in North Carolina
Series title:
Conservation Genetics
DOI:
10.1007/s10592-017-1037-4
Volume:
19
Issue:
1
Year Published:
2018
Language:
English
Publisher:
Springer
Contributing office(s):
Leetown Science Center
Description:
13 p.
First page:
207
Last page:
219
Country:
United States
State:
North Carolina