IMIS - Marine Onderzoeksgroepen

Nineteen tracks were successfully estimated using light-based geolocation and refined using remotely sensed sea-surface temperature data and unscented Kalman filtering. All but one shark made rapid directed movements north of New Zealand to subtropical or tropical regions, including eastern Australia, the Coral Sea, New Caledonia, Vanuatu, and Tonga during the austral autumn, winter, and spring. Four instances of return migration to New Zealand waters were observed, including three to the tagging location. Adult male and juvenile White Sharks occupied a variety of pelagic subtropical and tropical habitats for at least 5–7 months of the year. Sharks were resident in New Zealand waters for up to 5 months post-tagging, with only one shark, an immature female, overwintering in New Zealand. No shark moved between the Chatham Islands and Stewart Island, but mixing of these sharks may occur off northeast North Island, eastern Australia, and Norfolk Island and in the Coral Sea. Effective conservation of White Sharks in the southwest Pacific is dependent upon ongoing international cooperation and the implementation of effective protection measures covering both national and international waters.