ABSTRACT
The movements and behavior of 22 juvenile White Sharks, Carcharodon carcharias [1.75-2.6 m total length (TL)], were monitored in eastern Australia using satellite tracking and pop-up archival tags, providing a total of 1,941 d of data. Broad-scale movements were primarily coastal, were highly directional with high angular concentration values r (mean r = 0.81; SD = 0.16), and ranged over 2,000 km of the Australian coastline from eastern Tasmania to southern Queensland. One 2.1-m male also traveled 3,600 km across the Tasman Sea to New Zealand, through Cook Strait, and east onto the Chatham Rise. Directional movement was interspersed with periods of temporary residency denoted by signi¢cantly lower r values (mean r = 0.22; SD = 0.17) and a highly restricted geographic footprint. Residency sites were limited in number, and season of occupancy suggesting that juvenile White Sharks have a relatively small number of interconnected preferred habitat areas in eastern Australia. The consistent occupancy of two residency sites over multiple years, the Corner InletNinety Mile Beach region off eastern Victoria and the Port Stephens region of New South Wales, de¢ned these as seasonal nursery areas. On-shelf shark activity was primarily shoreward of the 120-m depth contour in nursery areas. Sharks moving between nursery areas showed a propensity to travel over a corridor spanning bottom depths of 60-120 m, with 55% of all ARGOS positions located over this zone. This depth zone includes relic coastline structures in eastern Australia, which may offer cues for navigation or enhanced foraging opportunities by providing focal areas for prey species. However, sharks also made occasional dives to 300-500 m when traveling and when offshore. The maximum depth recorded by a 1.9-m female was 984 m. Sharks showed considerable
plasticity in swimming behavior, recording most patterns previously identi¢ed in juvenile, subadult, and adult stages of this species. The similarity in the dominant temperature range experienced by juvenile White Sharks between our data and other studies suggests a propensity to occupy waters of 18-20ºC. Nursery areas in eastern Australia are coincident in time and space with aggregations of various ¢n¢sh species that provide suitable prey and coincided with areas of seasonal upwelling and subsequent nutrient enrichment. The smaller sizes of juveniles recorded from the Corner Inlet region of eastern Victoria suggests that pups may initially recruit to this nursery area prior to establishing a seasonal migratory pathway along the east coast to the Port Stephens nursery area of central New South Wales. The potential exists for juvenile White Sharks to be taken as bycatch in nearshore, shelf, and slope ¢shing activities in the vicinity of these nursery areas. Forays seaward of the shelf break, offshore diving behavior, and open-ocean travel may also expose juvenile White Sharks to incidental capture in offshore pelagic ¢sheries previously considered not to pose such a threat.
