Estimating Sturgeon Abundance in the Carolinas Using Side-Scan Sonar and Bayesian Models

Thursday, September 12, 2013: 4:00 PM
Harris Brake (The Marriott Little Rock)
H. Jared Flowers , North Carolina Cooperative Fish and Wildlife Research Unit, Department of Applied Ecology, North Carolina State University, Raleigh, NC
Joseph E. Hightower , Department of Applied Ecology, U.S. Geological Survey, North Carolina State University, Raleigh, NC
Populations of endangered Atlantic sturgeon (Acipenser oxyrhincus) and shortnose sturgeon (Acipenser brevirostrum) in North and South Carolina have been significantly reduced from historic levels by a combination of intense fishing and habitat loss.  The conservation status of these species creates a need for estimates of current abundance. Hydroacoustics, such as side-scan sonar, have advantages over traditional techniques, such as the ability to sample large areas efficiently and potentially survey fish without physically handling them – important for species of conservation concern.  Our objective was to use data from side-scan sonar surveys to create estimates of abundance for sturgeons.  We surveyed lower reaches of six rivers in North and South Carolina, near the saltwater/freshwater interface, using a combination of side-scan sonar, telemetry, and video cameras (to sample jumping sturgeon) during summer 2011. We used both occupancy and N-mixture models with data acquired from side-scan sonar surveys to estimate abundance of sturgeon in each river. Estimated total abundance of sturgeon >1 m in length for all six rivers combined was greater than 600 individuals. The Pee Dee/Waccamaw and Santee Rivers in South Carolina had highest and lowest estimated abundances, respectively.