Evaluation of Smallmouth Bass in Abrams Creek and Little River Within Great Smoky Mountains National Park

Shaffer, Gregory

Smallmouth bass Micropterus dolomieu were sampled during Summers 2002 and 2003 from two streams within Great Smoky Mountains National Park (GSMNP), Little River (freestone stream) and Abrams Creek (limestone stream), to determine age and growth, size structure, abundance, mortality, and recruitment for smallmouth bass within GSMNP. Smallmouth bass were sampled using visual observation and electrofishing. Growth rates in Abrams Creek and Little River were significantly different (P<0.05). von Bertalanffy growth curves predicted smallmouth bass in Abrams Creek would reach 305 mm (12 inches) in 6.7 years, and reach the same length in Little River in 8.1 years. Proportional stock densities of smallmouth bass in Abrams Creek and Little River were 10% and 13%, respectively. Summer 2003 population estimates averaged 250 bass/ha (22.5 kg/ha) in Abrams Creek and 46 bass/ha (4.5 kg/ha) in Little River. Total annual mortality for ages II to VII was 43% in the Abrams Creek population and 28% in Little River’s population. Recruitment variability was 47% and 94% in Abrams Creek and Little River, respectively. When compared to other streams in Tennessee, smallmouth bass in Abrams Creek and Little River exhibited slower growth and possessed a lower abundance of preferred size and larger bass, yet had similar mortality and recruitment rates. Distribution and habitat utilization of smallmouth bass in Abrams, Hazel, and Eagle Creeks, and Little River were determined using underwater observation. Upstream distribution of smallmouth bass in Abrams Creek and Little River was stopped by large cascades, while smallmouth bass in Hazel and Eagle Creek were halted by a loss of suitable habitat. Amount of run and riffle habitat, discharge, and surface area of site were significant variables when predicting smallmouth bass abundance in Abrams Creek and Little River. Using the population dynamics, distribution, and habitat utilization, a sampling protocol was developed for GSMNP fisheries biologists. Smallmouth bass should be sampled during low discharge periods. The sampling technique used should be based on management objectives set by GSMNP biologists. Assuming low discharge during sampling, electrofishing should be used if length-weight data is desired; however, snorkeling should be employed if population estimates are desired.