Around 50 green turtles have been saved at remote Raine Island as part of an initiative to improve survival rates of this vulnerable species in the face of climate change.

Rock ledges and eroded areas at the island, which is the world's largest aggregation site for nesting green turtles, have been fenced off to stop turtles falling over the edge and dying in the sun as they attempt to return to the ocean after nesting.

Raine Island supports the largest gathering of green turtles in the world, with in excess of 100,000 turtles recorded in waters around the island and in excess of 14,000 recorded on the beach in one night.

Great Barrier Reef Marine Park Authority Chairman Russell Reichelt said protecting nesting green turtles was vital to maintain future turtle populations on the Reef and within the Indo-Pacific region.

"Climate change threatens to dramatically influence the future ratio of male and female turtles, which can impact on their population," Dr Reichelt said.

"The sex of green turtles is determined during incubation by environmental conditions particularly the temperature of their nest, with warmer temperatures producing more female hatchlings.

"Based on predictions of warming over the coming 50 years, it's predicted that we'll have far more female than male hatchlings, and this may have a long-term impact on the population.

"We're focusing on protecting the adult turtles to reduce the risk of the species' decline.

"Field staff recorded in excess of 50 turtles that died last year by falling over one section of the island's rock ledges and eroded areas.

"In comparison, there have only been two deaths recorded this nesting season since these sections of the ledges were fenced.

"This is a significant achievement given mature female turtles have the potential to produce between 4000 and 8000 eggs over their lifetime.

"While this is only the first time fencing has been installed, the success of this initiative will mean hundreds of green turtles will be saved over the coming years, and fencing of other ledges is planned this year."

The Raine Island Recovery Project, led by QPWS Senior Ranger Dr Andrew Dunstan, is a joint initiative between the Great Barrier Reef Marine Park Authority, Queensland Parks and Wildlife Service and Traditional Owners as part of the Great Barrier Reef Field Management Program.

Rangers from the Queensland Parks and Wildlife Service constructed small fences along the edge of the rock ledge as a first stage of the project.

They targeted areas where carcasses have been found after turtles had previously fallen on their backs and been unable to free themselves.

Through the Field Management program, GBRMPA and the Queensland Government manage a range of activities including wildlife monitoring and protection, island management, and enforcement and incident response.