If you read my previous post, you’ll know that I’ve just spent two weeks living on Bare Sand Island in the Northern Territory working as a sea turtle research assistant. The trip was with AusTurtle Inc, who have been collecting sea turtle data for about 20 years. It was an absolutely incredible experience, highly recommended to anyone with an interest in turtles, marine ecology, fishing or island living!
Bare Sand is a remote and isolated island about a 90 minute boat ride from Cullen Bay in Darwin. There’s a composting toilet, some tents, a small shelter … and not much else. Despite this, the island is popular due to its large population of flatback sea turtles that return to nest each year.
During high tide, female flatback turtles slowly make their way out of the sea to the grassy sand dunes looking for suitable nesting sites. When she’s chosen an area, she will create a depression in the sand known as a body pit. Afterwards, she’ll delicately use her hind flippers to create an egg chamber. Once the chamber is complete, she’ll lay about 50 eggs, taking anywhere up to 40 minutes.
When she’s all done, we move in to collect data.
Each returning turtle has titanium identification tags that need to be read. We measured the curved carapace (shell) lengths and widths, GPS’d the nest locations, removed any problem barnacles and recorded details about any identifying features or damage present for each nesting turtle. This data is used in a variety of ways, including tracking growth and providing survival estimates.
The eggs incubate for about 50 days before hatching. Unfortunately, flatback hatchlings have about a 1 in 2000 chance of reaching maturity. We helped to give newborns the best chance of success by monitoring for hatched nests every morning. We scanned the beach for hatchling turtle tracks, which we used to help locate the nest. All nests were dug up, so that we could use the egg shells to determine the clutch size.
At most nests, there would be a few straggler hatchlings that didn’t quite make it out of the nest in time, which was always exciting.
If the hatchlings were healthy, we’d keep them at camp until we could safely release them at nightime. Any underdeveloped or injured hatchlings were sent to Charles Darwin University’s turtle rehabilitation centre on the mainland.
In addition to flatbacks, we were also lucky enough to see some olive ridley hatchlings, another far less common nesting species at Bare Sand Island. Trips out on the boat during the day meant I also got to see foraging green and hawksbill sea turtles, both vulnerable in this area.
My two weeks on Bare Sand were unbelievable, and ended all too soon. I feel so lucky to have been able to spend so much time with sea turtles, such beautiful, majestic and under-researched animals. I hope to return soon!