Introgressive Status, Population Genetic Structure, Phylogeographic History and Individual-Level Resource Specialization of the Guadalupe Bass Micropterus treculii
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Introgression between Guadalupe bass Micropterus treculii and introduced smallmouth bass M. dolomieu poses a threat to Guadalupe bass within its native range. Restoration efforts include stocking hatchery-reared Guadalupe bass with the effectiveness of this strategy appearing to be dependent on the intensity and duration of stocking. However, changes in introgression levels in other Guadalupe bass populations are not known. Additionally, streams within the range of Guadalupe bass have a complex geologic and hydrologic history that include stream captures and changing hydrologic connections associated with sea level changes resulting from glacial influences. How these historical and contemporary (e.g. stocking hatchery-reared fish) factors affect the population genetic structure of Guadalupe bass is not known. Because stocking of hatchery-reared fish can result in losses of genetic variation, it is also possible that phenotypic variation, including variation in resource use, might also be altered in these populations. My research focused on addressing three primary objectives: 1) assessing levels of introgression between Guadalupe and smallmouth bass across the range of Guadalupe bass, 2) evaluating historical and contemporary factors affecting the population genetic structure of Guadalupe bass, and 3) assessing individual-level resource specialization as it relates to genetic and morphological variation among populations. The results of these studies provide a greater understanding of the phylogeographic history of the Edwards Plateau region and of the effects of genetic diversity in wild populations on population niche dynamics.