Age and growth of the Redeye Bass complex (Redeye, Tallapoosa, Warrior, and Cahaba basses) in the Mobile River basin, Alabama

ABSTRACT Objective To inform the conservation and management of the popular sport fish comprising the Redeye Bass Micropterus coosae complex, our objective was to estimate growth parameters of Redeye Bass complex species (REB) from all four native watersheds in the Mobile River basin, Alabama, where they occur. Methods We used single-nucleotide polymorphism genotyping to confirm the genetic purity of fish that were used to estimate mean total length at age across all four REB by utilizing von Bertalanffy growth curves and catch curves that were fitted to estimate survival/mortality rates. Results We collected a total of 322 genetically pure REB specimens via hook-and-line angling from 27 different streams in the Black Warrior (N = 47 fish), Coosa (N = 126), Cahaba (N = 52), and Tallapoosa (N = 97) River drainages. Growth analysis indicated that members of the Redeye Bass complex are the slowest growing of the black basses Micropterus spp., with asymptotic length parameter estimates ranging from 257 to 308 mm. We predicted that REB from these drainages would attain a length of 254 mm after 6.9 years (Tallapoosa River drainage) to 10.3 years (Black Warrior River drainage). Catch-curve analysis indicated that the total instantaneous mortality rate did not differ among drainages, and the estimate of 0.38 year−1 was within the range of expected background natural mortality, which suggests that fishing mortality is likely low in these systems. Conclusions Very little is currently known about basic life history characteristics of endemic black bass species, such as the Redeye Bass complex. Knowledge of species-specific growth rates and fishing mortality should better inform the conservation and management of these unique riverine species by providing data for length and bag limit considerations and by establishing baseline data to continue the monitoring and evaluation of growth parameters.