Rare sightings of leatherback turtles off the coast of Bundaberg could signal a return of nesting on Australian shores.
Passengers and crew aboard recent whale-watching tours have been treated to three sightings of the rare creature, including a mating pair.
While loggerhead turtles are often spotted, tour operator Brett Lakey said catching a glimpse of a leatherback was breathtaking.
"On our last tour of the season, a leatherback came right up between the boat and the whales," he said.
Leatherbacks are the world's biggest sea turtles, growing to more than 1.5 metres long in shell.
They migrate through Queensland waters during spring.
Col Limpus, chief scientific officer with the threatened species operations of Queensland Parks and Wildlife Service, said people often mistook the large creatures for other objects when they were at the surface.
Hope for a threatened species
Sightings of mating leatherback turtles are especially rare, with the last leatherback turtle breeding season in Australia taking place 25 years ago.
The main nesting site was between Agnes Water and Bundaberg, about 80 kilometres from where the mating pair was sighted.
Dr Limpus said the population was almost at crisis level in the Pacific after many have become tangled in equipment laid by fisheries in the 1960s and 1970s.
The majority of recent mortalities recorded in Australia were caused by traps set up by lobster fisheries in Tasmania and Victoria.
"They feed near the surface on jellyfish and get tangled up in ropes to floats," Dr Limpus said.
Researchers had been discussing about whether to regard leatherback turtles as extinct as a breeding species in the region, he said.
"Now the whole prospect has changed."
The female turtle might not lay near to where the courtship occurred, but Dr Limpus said researchers had their fingers crossed that they would see a female turtle come up the beach.
"They could possibly migrate to the Solomons or New Guinea where there's still a remnant of leatherback nesting.
Looking for a cool change
The leatherback sightings come as the first flatback turtle arrived on Mon Repos beach for nesting season on October 9, a month earlier than expected.
Dr Limpus said it was the earliest record of a turtle nesting at Mon Repos off the Woongarra Coast in 54 years of monitoring.
The turtle season is a significant tourism drawcard, with more than 30,000 people visiting the Mon Repos Turtle Centre each year.
The arrival could indicate the turtles are adapting to climate change.
"As the beaches are getting excessively hot for them in mid-summer, we now see them starting their nesting earlier when beaches are cooler," Dr Limpus said, adding that the change in habit was encouraging.
