Declining green turtle numbers spark urgent conservation effort in northern Australia’s marine park

A groundbreaking collaboration between Indigenous rangers and scientists is shedding light on the health of northern Australia’s marine life. Watch the moment a turtle is returned to the ocean.

A dramatic decline in green turtle nesting on Croker Island has sparked a groundbreaking research project led by Charles Darwin University (CDU) and First Nations Rangers.

Aerial surveys comparing turtle nesting sites from the 1990s to 2024 have revealed a 78 per cent drop in nesting activity, raising alarm bells for the future of the species in the Northern Territory.

A pod of Coastal Bottle Nose Dolphins near Croker. Picture: Charles Darwin University / Supplied.

With funding from the Australian Government, CDU scientists, the World Wide Fund for Nature (WWF), Garngi and Mardbalk Rangers are working to better understand the challenges facing marine life in the Arafura Marine Park.

CDU Senior Research Associate Dr. Carol Palmer said the Northern Territory is home to key marine species, including dolphins, humpback whales, and Bryde’s whales — yet research in the region has lagged due to its remoteness and high costs.

CDU RIEL PhD candidate Natalie Robson and Senior Research Associate (Cetaceans and Marine Megafauna) RIEL Dr. Carol Palmer. Picture: Charles Darwin University / Supplied.

“We know these waters are critical habitats, but until now, much of the research has focused on the east and west coasts of Australia,” Dr Palmer said.

PhD candidate Natalie Robson highlighted concerns over rising sand temperatures reducing the number of male turtles, which could impact future populations.

“The sex ratio is becoming heavily skewed towards females, with 71 per cent of adults being female compared to only 20 per cent male,” Ms Robson explained.

CDU - action shot of the Survey Team from the water. Picture: Charles Darwin University / Supplied.

The study also aims to map key foraging and migration routes to establish a baseline for turtle populations, helping guide conservation strategies.

Northern Land Council Chair Matthew Ryan said the collaboration empowers rangers to combine cultural knowledge with scientific research, developing conservation strategies to protect eggs from threats like feral pigs and goannas.

Originally published as Declining green turtle numbers spark urgent conservation effort in northern Australia’s marine park