Turtle population study underway at Agincourt Reef

29th of May 2025

Charli, Rocket, Tripod, T-Bone and Little Foot are some of the names of many green sea turtles that call home to the waters surrounding Quicksilver’s Agincourt Reef platform (AG3).

Researcher and part of Quicksilver’s Reef Biosearch team of marine biologists, Heather Platt, has been conducting research into the turtle population here since February and through photo identification has to date identified 29 green sea turtles.

The study into the population is highlighting the AG3 area’s ecological importance (approximately 17,500sqm) for feeding, residence and transit of the species. 

“All of our documented green turtles are immature, so our AG3 site must be a great place for them to spend their juvenile years. The first photographic record we have of Charli dates back to October 2023, and as this study continues, it will be interesting to learn how long these residents typically hang around before finally venturing off,” said Heather.

Turtles have their own unique patterns of facial scales that remain stable throughout life and each individual has been photo identified during in-water surveys while snorkelling.

“Because they lack facial symmetry, video is also taken to ensure accurate identification of left and right sides. While some turtles have received nicknames, all individuals are assigned alphanumeric designations, and the sightings are recorded in a database.“

“Our data is being shared with Sea Turtle Observatory research collecting data from all along the Queensland coast, so it's possible that one of our turtles will one day be recognised at one of the many Great Barrier Reef breeding sites.”

The turtle research is being conducted as part of the Quicksilver’s site stewardship of this premier reef location. In collaboration with the Reef Authority, site stewardship plans identify the incredible marine biodiversity and overall health of our primary reef sites. In an earlier and ongoing study, over 110 different species of corals have been found at Quicksilver’s Agincourt Reef platform. 

With six of the world’s seven species of marine turtles found on the Great Barrier Reef, the green turtle (Chelonia mydas) is the most abundant. Primarily feeding on seagrass and algae, they are a crucial part of the marine ecosystem.

Generally, green sea turtles reach maturity between 30-50 years of age. An adult green turtle will have a straight carapace (shell) length of 65-90 cm. The green turtles identified at the Agincourt 3 platform site mostly range between 45-55 cm. 

Pictured: Heather points out Charli the green sea turtle during a guided snorkel tour