A review of the importance of south-east Australian waters as a global hotspot for leatherback turtle foraging and entanglement threat in fisheries

Australia’s largest sea turtle is the leatherback (Dermochelys coriacea). Leatherbacks do not nest, or only rarely, in Australia, and hence receive relatively little research attention. Here we review the knowledge of leatherback turtle occurrence in south-east (SE) Australia, drawing on sightings information as well as satellite tracking data from turtles equipped at their nesting beaches in Indonesia, the Solomon Islands and Papua New Guinea that then travelled to Australia. These data reveal that SE Australia likely provides a globally important foraging area for this species. Sea turtle temperatures assigned to sightings of live leatherbacks, showed 95% were seen at SSTs ≥ 14 °C. Similar to other parts of the world, such as the North Atlantic, the 12–15 °C isotherms likely constrain the seasonal pole-wards migration of leatherbacks searching for their gelatinous prey. Climate warming is likely moving the foraging range of leatherbacks poleward. This study also highlights the vulnerability of this SE Australian population to anthropogenic threats. Of 605 sightings of leatherbacks, 11.6% were of dead individuals, generally washed ashore, in most cases likely after entanglement in fishing gear.