Satellite and DNA data has revealed significant numbers of critically endangered hawksbill turtles either nest and live in Queensland or travel long distances to forage here – making improved protection in northeast Australia and the reefs surrounding Cape York critical to saving the species.
Led by WWF's Global Marine Turtle Conservation programme and the University of the Sunshine Coast, a recent study used satellite-tagging and genetics to track turtles from Papua New Guinea’s Conflict Islands – and found they travel over 1,000 km to reach the Great Barrier Reef to forage.
A separate study discovered hawksbills satellite-tagged in northeast Queensland’s Milman Island stayed in Australian waters, mostly swimming north to forage in Torres Strait and around to western Cape York. Both papers on the critically endangered species were published recently in Frontiers in Marine Science
Northeast Queensland’s population of hawksbills is considered at risk of extinction within a decade and there are fears a similar decline could be occurring across the larger southwestern Pacific population.
The research showed the importance of safeguarding hawksbill migratory routes and foraging habitats in north-east Australia. said Christine Madden Hof, a PhD candidate at the University of Sunshine Coast and leader of WWF’s Global Marine Turtle Conservation programme, who co-authored both papers.
“It is critical not just for the severely declining Milman Island population, but for hawksbill populations across the entire western Pacific," Ms Madden Hof said
Threats to the hawksbill turtles include fishing nets and ghost gear, direct harvest, and increasing sand temperatures due to climate change. In western Cape York, where there is currently little to no protection, the mortality risk to hawksbills was rated high to very high.
Simon Miller, a co-author of the Queensland research and Great Barrier Reef fisheries expert at the Australian Marine Conservation Society said the findings demonstrated why gill nets had to be removed from the Great Barrier Reef and why new net-free areas were urgently needed in the western Cape.
“There is also a clear need for greater independent scrutiny of commercial fishing in hawksbill home ranges to give us an accurate picture of what is being caught,” he said.
Milman Island is the main nesting beach for what used to be a globally significant population of genetically distinct hawksbills known as the northeast Queensland stock.
Route taken by hawksbills tagged on Milman Island
Hawksbills in western Cape York face many threats; maps shows gillnet and ringnet fishing pressure
Genetic sampling of female hawksbills nesting in the Conflict Islands’ group and about 1,000km further north in Kavieng revealed they are significantly different from one another and all other known Asia-Pacific stocks.
With the addition of these two, nine genetically distinct populations have now been identified in the Asia-Pacific region, but researchers believe there are many more. They say each will need to be managed separately to ensure population recovery.
Co-author Hayley Versace, manager at Conflict Islands Conservation Initiative said the Islands were one of the most important sites in PNG for hawksbills, shared across vast migratory routes, with Australia and other Pacific nations.
“We need to continue to support local communities to collectively manage this resource for future generations to come,” she said.
While PNG has no legislation to protect hawksbills, researchers and conservationists hope that could change given their plight.
Vagi Rei, Manager Marine Division from the Conservation and Environment Protection Agency of Papua New Guinea, said sea turtle harvesting for shell, meat and eggs continues in PNG and the Torres Strait in Australia under the Torres Strait Treaty with no legislative or regulated quota limits.
“This study has highlighted the need for greater national protection for hawksbills but given the migratory and foraging connectivity to eastern Cape York, stronger regional co-management and cooperation between the PNG and Australian Government is required,” he said.
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