Life History and Population Structure of the Snail Bullhead in Nickajack Creek, Georgia
Peter C. Sakaris, Dontrece Smith, Evan Davis, and Bwefuk Macham
Abstract.—The snail bullhead Ameiurus brunneus is a freshwater species found in fast-flowing streams and rivers in the southeastern United States. Although the snail bullhead is secure in Georgia and North Carolina, this species is considered at least vulnerable in other southeastern states where it resides. Limited information exists about life history and overall population structure of this species. In this study, our main goals were to use mark–recapture techniques to estimate population size of snail bullhead and to describe life history of this species in Nickajack Creek, Georgia. A Schnabel multiple census revealed that about 246 snail bullheads (>130 mm total length [TL]) resided within a short (0.7 km) segment of the creek. During the study, 33 of 34 recaptured fish were found at their original capture locations. A strong relation between weight and total length was observed for the population in fall 2007, spring 2008, and fall 2010 (r 2 = 0.98–0.99, P < 0.01). Overall, lengths of sampled fish ranged from 41 to 261 mm TL, with most fish between 101 and 174 mm. Ages of snail bullheads ranged from 1 to 8 years. A von Bertalanffy growth model was derived for the population (L∞ = 235 mm TL, K = 0.377, to = –0.1). Catch-curve analyses indicated that snail bullheads had a 39.8% annual survival rate in fall 2007 and at a 43.9% survival rate in fall 2010. Our assessﾭment of this snail bullhead population should assist in management and conservation of this species.