Cooperative Fish and Wildlife Research Units Program: Oklahoma
Education, Research and Technical Assistance for Managing Our Natural Resources

Endemic to the Apalachicola River Basin of the southeastern U.S., the Shoal Bass Micropterus cataractae is a fluvial-specialist sportfish that is imperiled because of anthropogenic habitat alteration. To counter population declines, restorative stocking efforts are becoming an increasingly relevant management strategy. However, population-genetic structure within the species is currently unknown, but could influence management decisions like brood source location. Leveraging a range-wide collaborative effort to collect and genotype specimens with 16 microsatellite loci, our objective was to characterize range-wide hierarchical population structure and genetic differentiation of Shoal Bass, including an examination of structuring mechanisms such as relatedness and inbreeding levels. Shoal Bass were collected from 13 distinct locations throughout its range (N ≥ 17 per location). Our results revealed appreciable population structure, with five distinct Shoal Bass populations identifiable at the uppermost hierarchical level that generally corresponded with natural geographic features and anthropogenic barriers. Additional substructure was recovered within several of these populations, wherein differences appeared related to spatial isolation and local population dynamics. An analysis of molecular variance revealed that 3.6% of the variation in our dataset was accounted for among three larger river drainages, whereas 87.4% was within the 13 sample sites. Results provide a population-genetic framework that can inform future management decisions, such as brood source location, so that genetic diversity within- and among- populations is conserved and overall adaptability of the species is maintained.