Overwinter habitat use of young-of-the-year white sharks (Carcharodon carcharias) off the eastern United States

Abstract

Despite recent increases in the number of studies that have focused on the movements and habitat use of juvenile and adult white sharks (Carcharodon carcharias) in the Northwest Atlantic Ocean off the eastern United States, there is com-paratively little information on the movements of young-of-the-year (YOY) white sharks, particularly in the overwinter season. Simultaneous satellite and acoustic tagging were conducted on YOY white sharks in 2016 and 2017, and data from their first overwinter period (December through April) were analyzed. Tracks of 9 white sharks offer a preliminary characterization of overwinter habitat use. During 2 winter periods over consecutive years, YOY white sharks occupied continental shelf waters (bottom depths: <100 m) off the coasts of North and South Carolina with mean sea-surface tem-peratures of 14.9–21.2°C, mean sea-surface heights of −0.5–0.2 m, and mean chlorophyll-a concentrations of 0.4–2.8 mg/m3. Their overwinter habitat extended over 950 km south of the cur-rent essential fish habitat established for YOY white sharks; however, it did overlap with a seasonal closure area that restricts bottom longline fishing. These results provide preliminary evidence for the existence of an overwinter nursery area for YOY white sharks in U.S. waters of the Atlantic Ocean.