TRIPLE LEDGES: SONAR CHARACTERIZATION OF ROCKY CONTINENTAL SHELF-EDGE EXPOSURES OFF CHARLESTON, SOUTH CAROLINA

Multibeam sonar surveys were conducted on the continental shelf off Charleston, SC from aboard the NOAA Ship Nancy Foster in November 2006. We will describe a rocky hardground called Triple Ledges, a segment of a larger shelf-edge feature referred to as Doc's Rocks, located in water depths of 50 m. Triple Ledges has three distinct parallel outcrops of strata aligned roughly parallel to shore, beyond which water depths descend rapidly to more than 100 m. The site will be characterized using multibeam sonar bathymetry and backscatter analysis of the distributions of hardground and sediment, side scan sonar, ROV video data, and surface sediment samples. Data collected will be compared to other similar shelf-edge sites and essential fish habitats will be preliminarily assessed.