Spatial Ecology of Shoal Bass in Ichawaynochaway Creek, Georgia
Travis R. Ingram, Steven M. Sammons, Adam J. Kaeser, Rachel A. Katz, and Sean C. Sterrett
Abstract.—Shoal Bass Micropterus cataractae are fluvial specialists endemic to the Apalachicola-Chattahoochee-Flint River Basin that are considered to be in decline throughout their native range. Effective conservation requires a comprehensive understanding of the migratory behavior and multi-scale habitat associations of Shoal Bass with riverine shoals, the critical mesohabitat upon which the species depends. We assessed movement patterns and habitat use of Shoal Bass using radio telemetry in the lower 24 km of Ichawaynochaway Creek, a 6th-order tributary of the Flint River and one of the few relatively undisturbed streams inhabited by this species. In general, Shoal Bass exhibited relatively low movement rates with increased movement in the spring, and no tagged Shoal Bass migrated from the creek into the Flint River during the study period. Most study fish preferred moderate depths (<2 m) and swift velocities during the year, and higher velocities in the winter, potentially reflecting seasonal changes in flow. These conditions were routinely satisfied through occupation of a 9-km reach with a network of large shoal complexes. Shoal Bass exhibited a distinct preference for close proximity to large shoals, and an affinity for greater depth variability associated with edge and boundary conditions within discrete shoal complexes. Despite previous studies that have documented high movement of this species in other systems, these findings suggest that the Ichawaynochaway Creek Shoal Bass population may be relatively sedentary and associate to specific areas that provide suitable habitat. This may have implications for assessing the integrity, distribution, and abundance of suitable Shoal Bass habitat in small karst limestone streams, designing projects for restoration or enhancement of existing habitat, and gauging the species vulnerability to threats such as habitat loss, introgression, and hybridization.