In 2001, Tennessee Wildlife Resource Agency biologists sampled what morphologically appeared to be Alabama bass (Micropterus henshalli) in Parksville Reservoir (Tennessee River Basin). Alabama bass, which are morphologically similar to spotted bass (M. punctulatus), are endemic to the Mobile Basin and had never been previously stocked in Parksville Reservoir. This study sought to confirm the identification of this nonnative fish species in Parksville Reservoir and assess the extent of hybridization with other black bass species within the lake and surrounding water bodies (Chickamauga Reservoir and tributaries). We used five microsatellite loci known to be highly informative for the identification of spotted bass and Alabama bass to assess the taxonomic identity and extent of hybridization for putative Alabama bass samples collected from Parksville Reservoir (n = 63) and spotted bass collected from Chickamauga Reservoir and tributaries (n = 61). Of the 63 putative Alabama bass collected from Parksville Reservoir, 62 were classified as that species and one as a putative Alabama bass x spotted bass Fx hybrid. Two of 61 spotted bass collected from the Chickamauga Reservoir and tributaries were suspected Alabama bass x spotted bass Fx hybrids. Our data indicated that current levels of Alabama bass hybridization were low; however, competitive interactions between this non-native species and other black basses have the potential to severely jeopardize other Tennessee fisheries. Our data serve as valuable baseline data in an effort to clearly document the genetic, ecological, and demographic consequences (if any) of this illegal introduction.
