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PHYLOGEOGRAPHIC PATTERNS IN LARGE RIVER ECOSYSTEMS: GENETIC STRUCTURE OF SMALLMOUTH BUFFALO (ICTIOBUS BUBALUS) IN THE OHIO RIVER
Citation:
Sloss, B. L., M J. Bagley, F H. McCormick, AND E. B. Emery. PHYLOGEOGRAPHIC PATTERNS IN LARGE RIVER ECOSYSTEMS: GENETIC STRUCTURE OF SMALLMOUTH BUFFALO (ICTIOBUS BUBALUS) IN THE OHIO RIVER. Presented at 2003 Midwest Fish and Wildlife Conference, Kansas City, MO, December 7-10, 2003.
Impact/Purpose:
The objective of this task is to develop molecular indicators to evaluate the integrity and sustainability of aquatic fish, invertebrate, and plant communities (GPRA goal 4.5.2). Specifically, this subtask aims to evaluate methods for the measurement of:
fish and invertebrate community composition, especially for morphologically indistinct (cryptic) species
population genetic structure of aquatic indicator species and its relationship to landscape determinants of population structure (to aid in defining natural assessment units and to allow correlation of population substructure with regional stressor coverages)
genetic diversity within populations of aquatic indicator species, as an indicator of vulnerability to further exposure and as an indicator of cumulative exposure
patterns of temporal change in genetic diversity of aquatic indicator species, as a monitoring tool for establishing long-term population trends.
Description:
Genetic studies on populations of large river fishes provide a potentially useful but underutilized research and assessment tool. Population genetic research on freshwater systems has provided meaningful insight into stock structure, hybridization issues, and gene flow/migration. However, most genetic research has concentrated on stream and lake ecosystems, not populations of large river fishes. In general, populations of large river fishes have several characteristics that are unfavorable for molecular ecology research, especially large population sizes and high levels of migration. As a result, the metapopulation dynamics of big river fishes are poorly understood. Recent ichthyological research examining fish community structure and dynamics throughout the Ohio River has shown patterns consistent with three recognized reaches of the river (upper, middle, and lower) and consistent with biogeographical patterns reflecting the ancestral Teays River drainage. The smallmouth buffalo (Ictiobus bubalus) is a long-lived, large river fish species found throughout the Ohio River. As such, it represents an ideal "model" fish to examine large river metapopulational patterns. In an effort to examine fine-scale genetic structuring in the river, we sampled 357 smallmouth buffalo throughout the Ohio River, including representatives from 16 putative populations during the spring/summer 2001. Mitochondrial DNA sequences for the ND2 gene and nuclear microsatellite DNA variation were analyzed for evidence of population fragmentation and subdivision (phylogeographical patterns) throughout the river by phylogenetic and nested-clade analyses. Resolved patterns of genetic diversity will be discussed in terms of impacts due to maintenance of navigational channels, hydrological manipulations, and historical biogeographical influences.