Very little is known about the diving behaviour of flatback turtles, their diet or their foraging behaviour, but this is about to change with the deployment of daily diaries on flatback turtles in the Pilbara. A daily diary is the equivalent of a very smart ‘fitbit’ for a turtle, it records how deep they dive, how fast they swim, the number of flipper beats per minute, where they are and where they are heading.
One lucky male turtle at the feeding ground had a combination daily diary and video camera, a CATS-Cam (http://www.cats.is/), which was fitted with four suction cups that allow the camera to stick on the back of the animal. This type of camera has previously been deployed on whales and white sharks, this is the first time it was used on a flatback turtle and the team didn’t know if it would stick longer than a couple of hours. But it did! It stayed on for 56 hours before detaching from the turtle and floating to the surface.
Once floating at the surface, the transmissions from the Argos satellite tracker are used to locate the camera with an error of about 500m. Once within 500m of the camera, a Yagi antenna is used to listen to the signals sent by the VHF transmitter fitted to the camera and retrieve it.
The footage from the camera has revealed different types of foraging behaviours not previously described in flatback turtles. It also shows how the turtle can rest on the bottom for up to 1h, digging itself into the sand. Unfortunately this time no interaction with other turtles, nor predators were recorded.
Simple daily diaries without video cameras were also deployed on 4 other flatback turtles in the same foraging area. The data recorded by the camera will help analyse and ground-truth the data collected by the other daily diaries and interpret recorded behaviours.
The deployment of this camera was part of a project run by the North West Shelf Flatback Turtle Conservation Program to study flatback turtles at their foraging grounds and is a collaboration with Dr Adrian Gleiss and honours student Jenna Hounslow from Murdoch University.