Flatback Hatchlings Emerge on Avoid Island

By March 11, 2015 March 17th, 2015 Great Barrier Reef Islands

Flatback turtles are one of Australia’s most gorgeous marine species. They’re huge, almost one metre long as adults, and even their hatchlings are bigger than other sea turtles.

We’ve already monitored the nesting of adult females in November and December and now we’re back on Avoid Island to check the success rates of these nests. We’ll be digging up the old nests to count how many hatchlings have emerged. Most of the young turtles will have left by now, but our small group of five is hopeful that we’ll catch a glimpse of a late clutch as they make their way to the ocean. Dr Nancy Fitzsimmons, our turtle expert, assures us that flatbacks are the most gorgeous of any sea turtle hatchling, so we’re eager to get to the beaches as soon as possible.

We don’t have to wait long. We arrive in the middle of a beautiful Monday afternoon, and once we’ve dropped our bags off at Avoid HQ we’re immediately off to check out our first beach.

Clutches take about 8 weeks to hatch, so the nests we recorded in November and December will be empty, but Nancy’s keen eyes note fresh hatchling tracks in the sand, so late laying turtles must have visited after we left! We set about nest location using GPS coordinates and hand drawn maps, feeling a bit like we’re following a pirate map to buried treasure. Using long sticks we poke at small sections of the beach to feel for loose sand where a turtle clutch may have recently emerged. As the afternoon wears on the shadows keep us out of the hot sun, and the breeze is strong enough that our hard work feels easy. We dig using our hands instead of a shovel, as we don’t want to accidentally rip the empty shells. When we find a nest we carefully count the number of hatched eggs to determine how successful the nest was. A huge cyclone during the last season meant many of the 2013 nests were swept away, but this year we’re finding nests with almost 100% success rate, which is excellent news for these threatened turtles!

 

 Digging for turtle nests is a lot like reading a crime fiction novel. There are twists and turns and red herrings and when you think you’re almost at the end you realise what you were looking for was back at the beginning anyway.

 

Sometimes we dug huge holes in the ground, big enough to stand in, and then discover that the nest was near the surface, only 20cm away. Other times, we find a nest and begin careful excavation, only to realise that it wasn’t the nest we were actually looking for. We call these unmapped nests “freebies” and manage to find quite a lot of them over the week.

On our second day of digging, Nancy walks along the beach and her pinkie toe feels a soft spot in the sand. We (doubtfully) watch as she begins to dig. Since it takes us a map, a GPS and a probing stick to find nests, we’re a little wary of her magical “pinkie toe technique”, but as she pulls out a handful of sand she feels a little hatchling head, and we realised we’ve finally found a clutch that hasn’t left yet. Nancy quickly recovers the hole so the eggs can surface naturally, and we continue our work.

It isn’t until the next day that the hatchlings decide to emerge, and we’re all suitably awed by their gorgeous little flippers and the beautiful patterns on their carapace. Nancy tries to recall us to our work, but has a hard time dragging us away from watching the little guys as they awkwardly struggle down the beach. As soon as they hit the first wave it’s obvious they’re in an environment where they belong, as they immediately zip away into the ocean.

Unfortunately, we have to leave the island pretty suddenly after only three days of digging as a cyclone forms off the coast, but we put in a monumental effort and manage to find 60 of our 83 mapped nests, plus 15 “freebies”, giving us more than enough data to determine the nest success. There’s time for a quick “ocean shower” in the tidal pools before we’re on our way home. Our hands are rubbed raw from digging in the coarse sand, but we’re stoked that we’ve found more nests than we had originally hoped.

Blog post by Aly Ross Ecologist and WildMob Intern

Photos by Charlotte Beloe UNSW Conservation Biology Student

With thanks to our partners in conservation:

Dr Nancy Fitzsimmons (Associate Professor Griffith University)

Queensland Trust for Nature and managers of Avoid Island Refuge.

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