UQ measures the cost of baby turtles' dash for freedom / Scientific Frontline

UQ measures the cost of baby turtles' dash for freedom

Monday, December 15, 2008

Measuring baby turtle's swimming ability

Credit: University of Queensland

UQ research is uncovering the true cost of how baby turtles make their dash from hatchling in the dunes to the relative safety of the ocean.

Zoologist Dr David Booth, from UQ's School of Integrative Biology, said his research was aimed at discovering how much energy the hatchlings needed to reach safe deep water.

“The first few hundred meters that a newly hatched turtle swims are the most dangerous of its life,” Dr Booth said.

“Having run the gauntlet of air and land predators to make it to the sea, the tiny voyager must also evade hungry fish patrolling the beaches in its bid for freedom.

“Frantically swimming and surrounded by predators, as many as 30 percent die on their maiden voyage.”

Curious to know how much energy the youngsters need to reach safe deep water, Dr Booth measured the hatchling's oxygen consumption and found they have enough energy reserves to survive 10 days at sea without feeding.

Basing his research at the southern end of the Great Barrier Reef at UQ's Heron Island Research Station, Dr Booth took advantage of the unique laboratory facilities that are within meters of a green turtle nesting beach.

“At hatching time, I corralled nest in order to catch several youngsters as they reached the sand's surface about 100 meters away from the lab before they could reached the sea,” he said.

“I then fitted each hatchling with a Lycra swim suit with a chord attached to a force transducer, before setting the youngster free in a seawater aquarium.

“As soon as they entered the water, the youngsters began swimming quickly with their large front flippers, pulling against the force transducer as if they were swimming out to sea.”

Dr Booth said initially the animals swam very hard using their front flippers with their heads down, only switching to a ‘doggy paddle' as they came up for air before returning to fast front-flipper swimming.

“But as time drew on, the youngsters' activity slowed,” he said.

“They spent more time doggy paddling and less time pulling with their front flippers until they eventually began taking the odd break after about 12 hours.”

Calculating the amount of energy the hatchlings consumed during their 18 hour swim, Dr Booth said the turtles carried almost 10 times as much energy in their yolk remnants as they needed to reach safety.

“So the youngsters aren't at risk of running out of energy before making it to safety,” he said.

“They can probably survive 14 days in the open ocean before finding food.”

Dr Booth said the baby turtles were released into the ocean following the experiment. The experiment was conducted with the approval of the Environmental Protection Agency as well as UQ's ethical research guidelines.

The research was published recently in The Journal of Experimental Biology.

Source: University of Queensland