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Browsing by Author "Stepien, Carol A."

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    Population Genetic Differentiation of Walleye (Sander vitreus) across the Eastern Highlands of the United States
    Harris, Sheila C.; Palmer, George; Stepien, Carol A.; Hallerman, Eric M. (MDPI, 2023-12-29)
    Walleye is an important sportfish across eastern North America, is commercially fished in the Laurentian Great Lakes region, and has been introduced outside its native range. Thirty-eight Walleye populations within six watersheds across the Eastern Highlands and other portions of the native range were screened at eight microsatellite DNA loci to better understand evolutionary history and to inform fishery management and conservation efforts. Population genetic variation showed divergent assemblages of populations, respectively, living in the Mobile Bay, Mississippi River, Eastern Highlands (Tennessee, New, and Ohio Rivers), and Great Lakes drainages today. All estimates of effective numbers of breeding individuals were under 25, and all populations within all watersheds had ~15–20% inter-individual relatedness, likely attributable to the effects of both natural demographic processes and stocking. The extent of Eastern Highlands Walleye includes both the Ohio and Tennessee River basins.
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    SNP analyses highlight a unique, imperiled southern walleye (Sander vitreus) in the Mobile River Basin
    Zhao, Honggang; Silliman, Katherine; Lewis, Matthew; Johnson, Sarah; Kratina, Garret; Rider, Steve J.; Stepien, Carol A.; Hallerman, Eric M.; Beck, Benjamin; Fuller, Adam; Peatman, Eric (2020-08)
    Walleye (Sander vitreus) is a popular sportfish threatened by overexploitation, habitat destruction, and loss of genetic integrity due to non-native walleye stocking. Previous studies have identified a genetically distinct lineage of walleye in the Mobile River Basin, but further work is needed to assess population structure and introgression among this southern lineage and northern populations. Here we generated 2782 genome-wide single nucleotide polymorphisms (SNPs) to characterize the genetic uniqueness of southern walleye. We also found strong evidence for a historical declining population trend with reduced genetic diversity and effective population size in a southern walleye population of conservation importance. A 68-SNP panel was developed for rapid identification of genetic integrity and hybrid classification among northern and southern walleye, enabling us to identify an anthropogenic hybrid zone resulting from the previous introduction of northern walleye into the Black Warrior River drainage, Alabama. Our results highlight the need for conservation management of southern walleye in the Mobile River Basin, with our 68-SNP assay already being implemented in ongoing stream survey and captive breeding programs.