Abundance of Gulf Sturgeon in the Apalachicola River, Florida

Abstract

Abstract Gulf sturgeon Acipenser oxyrinchus desotoi a subspecies of Atlantic sturgeon A. oxyrinchus were once abundant in coastal rivers of the eastern Gulf of Mexico but have declined substantially due to habitat loss and overexploitation. Because relatively little is known about their population status in the Apalachicola River, Florida, we used capture–recapture data collected during 1982–1991 to assess the population of Gulf sturgeon at the Jim Woodruff Lock and Dam, which limits upstream migration. We estimated that about 100 fish greater than 45 cm total length were present below the dam, although the estimates were biased to an unknown degree because of violations of capture–recapture model assumptions. To obtain a less biased estimate, we conducted an intensive 10-week capture–recapture experiment in 1993 that accounted for most of the assumption violations. We also used radiotelemetry to test the assumption that the population remained closed to immigration and emigration during sampling. The 199...