Scientists are monitoring marine turtle populations and their breeding success, as well as working to relocate at-risk turtles and replenish sandy beaches to protect vital turtle breeding areas.
Dr Col Limpus heads up a Marine Studies team that works with a variety of native marine wildlife up and down the coast of Queensland – in Moreton Bay, along the Capricorn Coast, in Gladstone Harbour, in the Gulf of Carpentaria and in the waters of the southern and northern Great Barrier Reef.
The turtle breeding grounds of Raine Island.
One species of particular interest is the vulnerable green turtle, and there are concerns their overall populations on the northern Great Barrier Reef will decline markedly in the future, due the lack of breeding success over past decades.
Each year many green turtles, from a few thousand to approaching 100,000, swim thousands of kilometres from their feeding grounds in Indonesia, Papua New Guinea, Arnhem Land, the Gulf of Carpentaria, the Torres Strait and the Coral Sea region, to Raine Island – at the northern end of the Great Barrier Reef – to lay their eggs on its sandy beaches.
Col sums up the importance of the 21 hectare island and its surrounds. “Raine Island is really the jewel in the crown for the Great Barrier Reef. As an island, it has the largest concentration of breeding green turtles in the world.”
Col has been monitoring the green turtles on Raine Island since 1975 and became deeply concerned in the late 1990s when he found that annual hatching numbers had decreased. He assessed the condition of the beach – noting that there was now much less sand than before and that the water table could be seen in some places – and concluded that the reduced hatching success was due to sand depletion and changes in beach profiles.
An initial round of excavation work to replenish beach sand and reconfigure beach profiles along a small section of beach on the island has shown promising signs of helping to increase hatching success rates and a further section of beach was replenished in August this year.
Ongoing monitoring and maintenance work will continue to be needed on Raine Island to give the green turtles the best possible chance of hatching success.
Now a collaboration of partners, through the Raine Island Recovery Project, is working to help the green turtles. The Project is a five year, $7.95 million collaboration involving BHP, the Queensland Government, the Great Barrier Reef Marine Park Authority, Wuthathi and Kemer Kemer Meriam Nation (Ugar, Mer, Erub) Traditional Owners and the Great Barrier Reef Foundation.
Mon Repos turtle rookery
Mon Repos near Bundaberg is home to the South Pacific’s most significant loggerhead turtle nesting population.
Col and his team have been delivering Queensland’s annual loggerhead turtle monitoring program at Mon Repos for 50 years. Whereas flipper tag recoveries were used and continue to be used to monitor the movements of loggerhead turtles throughout their lives, a new generation of GPS satellite tags is also being used to provide accurate data on turtle movements and habitat use.
Visitors are welcome at the Mon Repos Turtle Rookery to learn about the loggerhead turtles and to participate in a guided turtle encounter by Queensland Parks and Wildlife Service rangers.
What can I do to protect our waterways?
From the Great Barrier Reef to Moreton Bay, all Queensland waterways are connected. There are things all of us can do to help. For example, avoiding littering, wherever you live, will prevent litter getting into waterways and making its way to the Great Barrier Reef. If you live in reef catchment areas, you can make sure soil and fertiliser stays on your property.