Molecular genetic markers can be used to assess genetic diversity, assign parentage, quantify inbreeding, and demonstrate structuring of populations across a system. Striped Bass Morone saxatilis, and Walleye Sander vitreus, are widely sought gamefishes in the Commonwealth of Virginia. Striped Bass along the Atlantic Coast and within the Roanoke River drainage exhibit low genetic variation. Screening 12 microsatellite DNA markers across the range to define population genetic structure, I found that anadromous populations in the Southeast and the Chesapeake Bay were differentiated from landlocked populations in the Roanoke River basin, with an average FST of 0.066. Range-wide, Striped Bass are differentiated between the landlocked and anadromous populations, which need to be managed separately. Within stocked populations in the Roanoke River basin, there have been impacts stemming from small numbers of broodstock propagated, and inter-individual relatedness is ~20% within stocked reservoirs. Walleye across the eastern native range were screened to better understand evolutionary history and to identify native marker alleles for the upper New River population. Population genetic variation at eight microsatellite loci showed differentiated stocks in Alabama, Mississippi River, Eastern Highlands (Tennessee, New, and Ohio Rivers), and the Great Lakes drainages. All estimates of effective numbers of breeding individuals were under 25, and all populations within all watersheds had ~15-20% inter-individual relatedness, likely effects of both natural demographic processes and stocking. The extent of Eastern Highlands Walleye includes both the Ohio and Tennessee basins. Although I did not identify new marker alleles for native New River Walleye, I determined that marker-assisted selection has increased the frequencies of existing marker alleles for the native stock. Application of the results of this project will contribute to better fisheries management for both of these important species. / Master of Science / Population genetics have proven useful for defining the most appropriate units for conservational management across a variety of species. Molecular genetic markers can be used to assess genetic diversity, assign parentage, quantify inbreeding, and demonstrate structuring of populations across a system. Striped Bass Morone saxatilis and Walleye Sander vitreus are both widely sought gamefishes in the Commonwealth of Virginia. I applied population genetic approaches to recognize genetically distinct groups of populations and to recommend genetically cognizant management practices. Striped Bass across the Atlantic Coast and in the Roanoke River drainage exhibit low genetic variation. After screening variation at 12 DNA markers, I found that Striped Bass are differentiated between landlocked and migratory populations, which need to be managed separately. Within stocked populations in the Roanoke River basin, there have been impacts stemming from propagation of small numbers of broodstock, and propagation and stocking practices will need to be changed to reduce apparent inbreeding depression. Walleye populations across the eastern native range were screened to better understand evolutionary history and to seek new marker alleles for the native upper New River population. After screening genetic variation at eight DNA marker loci, I identified four evolutionarily distinct stocks of Walleye across eastern North America. Although I did not identify new marker alleles for native upper New River native Walleye, I showed that marker-assisted selection has increased the frequencies of existing marker alleles over the past twenty years. The results of this project can contribute to better fishery management strategies for both of these important gamefish species.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/98505 |
| Date | 20 May 2020 |
| Creators | Harris, Sheila Catherine |
| Contributors | Fish and Wildlife Conservation, Hallerman, Eric M., Frimpong, Emmanuel A., Orth, Donald J. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Coverage | Virginia |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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