Studying the Flatback Turtles of Bare Sand Island – 2019

Written by: C. McGregor (u6079560)

In July of 2019 I had the privilege of spending a week on Bare Sand Island (BSI), volunteering with AusTurtle, observing the nesting female and hatching juvenile Flatback Turtles (Natator depressus). 

A newly emerged Flatback hatchling – Photo by author

Background
BSI is a small sand island located approximately 50km west of Darwin, Australia.  AusTurtle is a not-for-profit group, formed in 2004, that is dedicated to the monitoring and conservation of Flatback Turtles on BSI.  AusTurtle run research camps every year, over the peak of the nesting season, with the regular monitoring of the population enabling us to observe “the response of the nesting population and their eggs to changes in weather, initially, and more recently climate” (Guinea, 2019).  This is essential because despite the Flatback Turtle being a vulnerable Australian endemic species, little is known about them. 

Daily Duties
Whilst on the island, the volunteers had numerous duties each day.  Flatbacks nest at night, mostly around high tide, so our schedule was based around the high tides each day.  The first people began monitoring the beach for emerging turtles from 2 hours before high tide and when the first emerging turtles were spotted, the rest of the group then headed out in pairs to monitor different sections of the island.  We sat and waited until the turtles had dug their nests and begun laying, before we approached them.  The standard procedure was then as follows: measure the temperature of the eggs and the nest, record the serial numbers of the flipper tags (or attach new tags if needed), measure the length and width of the shell, record any defining features of the shell and record the GPS location of the nest.  All of this information was recorded on data sheets that were compiled the following day.  Finally, we would ‘cross off’ the turtle’s track to mark that the turtle and nest had been recorded.  This process was repeated for every turtle, until we were confident that there weren’t any more turtles nesting that night. 

The next morning, we had to be awake an hour before the morning high tide (5am on the first day!).  As a group, we would walk around the island checking for any nesting turtles and looking for any hatchling tracks or signs of an emerged nest.  If we found an emerged nest (indicated by hatchling tracks and a sunken patch in the sand), we would then dig up the nest.  We collected any hatchlings that were alive in the nest (to be released that evening), counted the number of empty shells (to determine how many hatchlings there were) and counted any unopened eggs.  The unopened eggs would then be opened to determine their ‘state’ (eg unfertilised, dead embryo, depredated, etc).  If there were more than 10 live hatchlings in a nest, we would take them back to camp to record details of the hatchlings.

Importance of Studying the Flatback Turtles of BSI
The research camps run by AusTurtle have helped to raise awareness about Flatbacks, with volunteers coming from around Australia and the world to work on BSI.  The data collected has been used to gain a better understanding of these turtles and how they are responding to changes in the environment, with numerous papers having been published based on Flatback data recorded on BSI.  Hopefully the information gathered about this species, on these research trips, can be used to inform strategies to protect this species.

About Biodiversity Conservation Blog

I am an Associate Professor at The Australian National University and convene a (very awesome) course called Biodiversity Conservation. Myself and students in the course contribute to this blog.
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