BOTTLENOSE DOLPHIN (Tursiops truncatus) Charleston Estuarine System Stock

STOCK DEFINITION AND GEOGRAPHIC RANGE The coastal morphotype of bottlenose dolphin is continuously distributed along the Atlantic coast south of Long Island, New York, to the Florida peninsula, including inshore waters of the bays, sounds and estuaries. Except for animals residing within the Southern North Carolina and Northern North Carolina Estuarine Systems (e.g., Waring et al. 2007), estuarine dolphins along the U.S. east coast have not previously been included in stock assessment reports. Several lines of evidence support a distinction between dolphins inhabiting coastal waters near the shore and those present in the inshore waters of the bays, sounds and estuaries. Photo-identification (photo-ID) and genetic studies support the existence of resident estuarine animals in several areas and similar patterns have been observed in bays and estuaries along the Gulf of Mexico coast (Wells et al. 1987; Balmer et al. 2008). Recent genetic analyses using both mitochondrial DNA and nuclear microsatellite markers found significant differentiation between animals biopsied along the coast and those biopsied within the estuarine systems at the same latitude (NMFS unpublished data). Similar results have been found off the west coast of Florida (Sellas et al. 2005). The Charleston Estuarine System (CES) stock is centered near Charleston, South Carolina. It is bounded in the north by Price Inlet and includes a stretch of the Intracoastal Waterway (ICW) approximately 13 km east-northeast of Charleston Harbor. It continues through Charleston Harbor and includes the main channels and selected creeks of the Ashley, Cooper and Wando Rivers. The CES stock also includes the Stono River Estuary, approximately 20 km south-southwest of Charleston Harbor, the North Edisto River another 20km to the west-southwest, and the estuarine waters and tributaries of these rivers (Figure 1). The southern boundary abuts the northern boundary of the Northern Georgia/Southern South Carolina Estuarine System stock, previously defined based on a photo-ID project (Gubbins 2002a,b,c). The borders of this region are defined based on long-term photo-ID studies and telemetry work (Speakman et al. 2006; Adams et al. 2008). The CES stock boundaries are subject to change upon further study of dolphin residency patterns in estuarine waters of North Carolina, South Carolina and Georgia. The Ashley, Cooper and Wando Rivers and the Charleston Harbor are characterized by a high degree of land development and urban areas whereas the Stono River Estuary and North Edisto River have a much lower degree of development. The Charleston Harbor area includes a broad …