Drone footage taken this week shows about 64,000 green turtles waiting around an island to come ashore to lay their eggs.
The turtles are on their way to Raine Island in Australia’s Great Barrier Reef.
Researchers at the Raine Island Recovery Project assist in the recovery of green turtle populations on Raine Island by addressing the issues of low nesting and hatching success and high adult turtle mortality.
The drone footage showing about 64,000 turtles is almost twice as many green sea turtles coming in to lay eggs as previously believed. Despite the mass numbers, the reality is more grim for the eggs that will become grown.
“Only one in a thousand hatchlings will reach maturity,” according to the Raine Island Recovery Project.
Dr Andrew Dunstan, from the Department of Environment and Science (DES), said researchers had been investigating various ways of measuring the turtle population.
“We were underestimating that a lot,” Dr Dunstan told the CNN news channel.
“We’re finding 1.73 times as many turtles with the drone and as we do when we directly compare with observer counts.
“The team can now go back and adjust the historic population estimates.”
According to the Great Barrier Reef Marine Park Authority, green turtles are found in tropical, subtropical and temperate waters around the world.
They are the most abundant of the six species of marine turtle found in the Great Barrier Reef World Heritage Area.
Found in sub-tidal and intertidal coral, as well as rocky reefs and seagrass meadows, they eat algae, seagrass, mangrove fruit and jellyfish.
A research paper published on June 8 shows that using drones is now the best way to count the sea turtles.
“Previous population survey methods involved painting a white stripe down the green turtles’ shell when they were nesting on the beach,” Dr Dunstan said.
The drone survey is part of the five-year, $7.95 million Raine Island Recovery Project.
It is a collaboration between BHP, the Queensland Government, the Great Barrier Reef Marine Park Authority, the Great Barrier Reef Foundation and the region’s traditional owners: the Wuthathi and Kemer Kemer Meriam people.
Great Barrier Reef Foundation managing director Anna Marsden congratulated the researchers.
“We’re seeing the world’s largest aggregation of green turtles captured in these extraordinary drone images, which are helping to document the largest turtle numbers seen since we began the Raine Island Recovery Project,” Ms Marsden said.
