Anadromous Sturgeons: Habitats, Threats, and Management

Abstract

<em>Abstract.</em>—The Gulf sturgeon <em>Acipenser oxyrinchus desotoi</em> is an anadromous species listed as threatened under the Endangered Species Act in 1991. We conducted a 3year tagging study to estimate population size, growth, mortality, and age composition for sturgeon in the Yellow River. Capture probabilities and population size were estimated using Program MARK and a Cormack-Jolly–Seber model. Total mortality of Gulf sturgeon was estimated using a Beverton–Holt mortality equation. Growth rate was determined from annuli on the leading edge of pectoral fin-ray. A total of 522 Gulf sturgeon captures were made, and 399 individual fish were tagged. The population estimates for the Gulf sturgeon over 3 years ranged from 500 to 911 fish. The age structure of the population suggests successful recruitment and a viable population. The total annual mortality estimate for Yellow River Gulf sturgeon was 11.9%. Growth rate for the Yellow River population was comparable to other populations of Gulf sturgeon. The Yellow River Gulf sturgeon population is a dynamic population based upon consistent age-classes as an indicator of successful recruitment, a large population size relative to most rivers where Gulf sturgeon are found, and estimates of mortality below the reported range for the species.