Genetic Assessment of Alabama's Redeye Bass (Micropterus coosae)

Abstract

The southeastern United States is a hotspot for aquatic biodiversity that is under constant threat of extirpation and extinction due to human disturbance. Molecular markers are relatively new tools that are applicable to conserving these many endemic populations by establishing genetic baselines of hybridizing populations, resolving taxonomic status, identification of genetically pure populations, and helping to better inform management plans for fish species. Of these, SNPs have become preferred due to their utility and reproducibility. Here, I describe the use of a 64 SNP panel diagnostic for the black basses (Micropterus spp.) to survey populations of redeye bass (M. coosae) in three of their native river systems in the Mobile River Basin: Tallapoosa River, Black Warrior River, and the Cahaba River. Redeye bass are native to the Mobile River Basin in Alabama and are one of a few black bass species with small geographic ranges. In my first study, I used a diagnostic SNP panel to survey a putative population of redeye bass in the Tennessee River drainage where they are not native. Genetic analyses confirmed the presence of redeye bass outside of their native range in Alabama and served as a baseline for future studies to investigate the presence of these sportfish and to follow these populations over time. Phenotypic identification is often employed by management agencies to quickly identify individuals in the field, which serves as the basis for population estimates, age and growth estimates, and other factors relating to the management of sportfish. A comparison of phenotypic identification with genetic identification of sympatric Alabama bass and redeye bass revealed substantial error in field identification of the two species and their hybrids. These data should inform management efforts of the ability of genetics to augment future surveys and studies involving these two species.

Redeye bass populations outside of Alabama are designated as species of special concern due to their hybridization with introduced Alabama bass. Little is currently known about the redeye bass populations in Alabama, which is a large portion of their native range. Here, I utilized a diagnostic 64 SNP panel to survey multiple populations of redeye bass across three large river systems in the Mobile River Basin. Hybridization was found to be occurring at very high levels in two of the three river systems and is facilitated by human disturbance. The baseline genetic survey provides a foundation for long-term monitoring of these range-restricted species and should greatly facilitate conservation studies in these unique species.