Piles of dead turtle hatchlings are lining Queensland's famous Mon Repos beach amid a heatwave which has pushed the sand's temperature to a record 75° Celsius.
While the majority of Loggerhead turtle hatchlings break free from their nests at night when the sand is cooler, those escaping in the day face overheating.
"They can't sweat, they can't pant, so they've got no mechanism for cooling," Department of Environment and Heritage Protection chief scientist Dr Col Limpus said.
"If they encounter very hot sand they just simply heat up. They slow down and that's the end for them.
"You really only have probably an hour or so in those really hot sands and it's terminal."
The extreme heat is also conducted down to the turtle's nest, pushing the temperature there to about 34°C, which is approaching the lethal level for incubation.
That is the hottest temperature recorded in a nest in more than a decade.
"We've got an increased mortality … that we haven't been seeing in years," Dr Limpus said.
The average hatchling survival rate is 85 per cent but due to the heat it is likely to be a lot lower this year.
The exact number of turtle deaths is not known at this stage, but hundreds have been seen dead on the beach.
The 1.6km Mon Repos beach is the most important breeding site for Loggerhead turtles in the South Pacific.
The majority of the region's turtles are hatched on the beach - some 200,000 in a usual season.
Rangers, scientists, volunteers working overtime
The rangers, scientists and volunteers at Mon Repos have been working around the clock to save as many clutches of hatchlings as they can from the heat.
Deceased turtles in the dunes lead them to the nests where some hatchlings may still be alive beneath the surface and they work quickly to dig them up, separating the dead from the living.
They are also relocating any new nests to hatchery areas underneath shade cloths, with sand surface temperatures under the shades up to 30 degrees cooler.
Dr Limpus said how the turtles respond to the relocation was yet to be seen.
A long-term option might be to introduce more trees to create shade in the dunes for the turtle nests, but for now the shaded shelters were doing the job, he said.