9781934874400-ch43
Black Bass Diversity: Multidisciplinary Science for Conservation
Evolutionary Genetic Diversification, Demography, and Conservation of Bartram’s Bass
Kenneth J. Oswald, Jean K. Leitner, Daniel Rankin, D. Hugh Barwick, Byron J. Freeman,Thomas Greig, Max Bangs, and Joseph M. Quattro
doi: https://doi.org/10.47886/9781934874400.ch43
Abstract.—The highly diverse freshwater ichthyofauna of the southeastern United States’ Atlantic slope is imperiled due to numerous anthropogenic insults to the region’s lotic environments. Damming, pollution, riparian destruction, and introductions of nonnative species have all contributed significantly to reductions in freshwater biodiversity. Bartram’s Bass (an as yet unnamed species similar to Redeye Bass Micropterus coosae), endemic to the Savannah River, is threatened with extirpation from multiple basin provinces via hybridization with introduced nonnative Alabama Bass M. henshalli and Smallmouth Bass M. dolomieu. Estimation of evolutionary and demographic parameters is critical to formulation of management plans designed to conserve this rare Atlantic slope endemic. Here we utilize analyses of DNA sequences from mitochondrial and nuclear loci to examine evolutionary patterns displayed by Bartram’s Bass. Phylogenetic reconstructions and genetic variance partitioning revealed appreciable levels of population structure throughout the Savannah River basin, and exact tests of population differentiation identified several management units. Coalescent analyses returned mean effective population sizes (Ne) for extant populations ranging from 415 to 3,228 individuals (median range 388–2,531 individuals), rather recent times since population separation within the drainage (mean range 999–73,282 years before present; median range 493–65,417 years before present), and high population migration rates (2Nem > 1) among higher-latitude provinces, particularly the upper Savannah and Seneca rivers. Estimates of phylogenetic and demographic parameters, taken in conjunction with introgression of nonnative alleles resulting from micropterid introductions into the Savannah River, present the need for a comprehensive, basinwide conservation strategy to ensure the long-term in situ preservation of Bartram’s Bass.
