198 National Marine Fisheries Service Fishery Bulletin First U.S. Commissioner established in 1881 of Fisheries and founder NOAA of Fishery Bulletin Abstract—Anthropogenic perturba- Abundance of endangered shortnose tions during the 19th and 20th cen- turies resulted in major declines in sturgeon (Acipenser brevirostrum) in the abundance of populations of shortnose sturgeon (Acipenser brevirostrum). Altamaha River in Georgia Despite the designation of this spe- cies as endangered, most populations Evan C. Ingram (contact author) are still not recovering. Abundance Douglas L. Peterson (retired) monitoring is needed to identify fluc- tuations in recruitment and survival; Adam G. Fox however, river- specific assessments are deficient throughout the range of this Email address for contact author:
[email protected] species. During the summer of 2011, we used anchored nets to fish a closed Warnell School of Forestry and Natural Resources population of shortnose sturgeon in University of Georgia the Altamaha River in Georgia. Mark- 180 East Green Street recapture tagging resulted in the cap- Athens, Georgia 30602 ture of 288 shortnose sturgeon (272 fish with unique marks and 16 fish Present address for contact author: School of Marine and Atmospheric Sciences recaptured) over 11 weekly sampling Stony Brook University occasions. Estimates of the abundance Stony Brook, New York 11790 of shortnose sturgeon were derived by using Huggins closed- capture mod- els. The preferred model incorporated effects of temporal variation on weekly capture probability and estimated an abundance of 2218 individuals (95% The shortnose sturgeon (Acipenser bre- characterized by slow growth, delayed confidence interval [CI]: 1424–3350), virostrum) is an imperiled species that maturation, and longevity.