Residency, space use and movement patterns of juvenile sandbar sharks (Carcharhinus plumbeus) within a Virginia summer nursery area

Abstract

Neonates and juveniles of many large coastal shark species occupy shallow inshore nursery areas during portions of the year. The identification of how these areas are used by large coastal shark populations is an important consideration in conservation and management efforts. An array of passive acoustic receivers was utilised to track the movements of 64 neonate and juvenile sandbar sharks within the Eastern Shore of Virginia summer nursery during the summers of 2003–2005. Residency patterns were variable during each year of the study, with younger sandbar sharks spending more time within the array area than older sharks. The number of detections was positively related to the distance of the receiver inshore from the inlet, indicating that young sandbar sharks preferentially utilise protected, shallow near-shore waters. Neonate and juvenile sandbar sharks tended to be detected more frequently within all areas of the inlet at slack tides, during the night and during early dawn hours. Periodogram analyses indicated that juvenile sharks tend to move in the direction of tidal currents. The present study documents large- and small-scale movement patterns of juvenile sandbar sharks and emphasises the importance of nursery-area habitats for this species.