Brisbane, May 18 (IANS): Flatback turtles must counter the effects of currents from the moment they hatch, if they are to remain in the Great Barrier Reef in north-eastern Australia, a study published on Monday revealed.

The study, led by Natalie Wildermann of Queensland state's James Cook University, found it is impossible that baby flatback turtles would remain within the boundaries of the reef if they simply drift with the current, Efe news agency reported citing the study.

The researchers used computer models of ocean currents to show that the hatchlings must swim actively against the currents to remain in the reef.

"It had been thought that marine turtle hatchlings drift passively in ocean currents, and that these currents would take them to favourable habitats for their development. But recent studies, including ours, show that the hatchlings actually disperse actively," explained Wildermann.

"So they swim, and they swim in a certain direction to reach or avoid some currents," she added.

Although researchers have not determined how the turtles know where to swim, they suspect that either magnetic noise or basic chemical cues help them to navigate.