No flatback turtle from Eastern Australia has been found outside of Australia’s continental shelf for at least 50 years. One of the great mysteries with this species is that it is unknown why they do not venture into the open ocean. James Cook University (JCU) researchers are uncovering the mystery by releasing 25 baby flatback turtles equipped with small, solar-powered GPS transmitters. It is hoped the hatchlings will help fill in knowledge gaps about the early years of juvenile marine turtles, named ‘the lost years’ because they are unknown to science.
The findings from current research prove that hatchlings must actively swim to sites within the Great Barrier Reef – they swim in a certain direction to reach or avoid ocean currents. This is contrary to the thought that marine turtle hatchlings drift passively in currents to take them to favourable habitats. Studies using computer modelling of ocean currents confirmed that it is impossible for hatchlings to remain inside the boundaries of the Great Barrier Reef (GBR) by simply drifting with currents.
JCU student Natalie Wildermann and her co-researchers believe that as hatchlings, marine turtles quickly adapt to the turbid coastal waters of the GBR and thrive in its conditions. However, the mystery still remains as to how hatchlings know where to swim. “The actual cues that turtles use to know when, where and in which direction to start swimming are still unknown,” she said. The discovery that they are active swimmers, not passive drifters, during the hatchling life stage is a big step to recovering these ‘lost years’.
The project is receiving support from the Nyangumarta Traditional Owners who are joint managers of Eighty Mile Beach Marine Park.