x Abu Dhabi, UAETuesday 16 January 2018

Sea turtles tracked while swimming to cooler waters

Conservations are installing satellite tracking devices on sea turtles to monitor their movements as they begin seeking cooler waters for the summertime.

A Hawksbill turtle with a satellite tracking device leaves Masirah island in Oman after laying her eggs.
A Hawksbill turtle with a satellite tracking device leaves Masirah island in Oman after laying her eggs.

SHARJAH // The arrival of summer is the trigger for plans to escape to cooler climes.

This is as true for UAE residents as for the hundreds of endangered marine turtles that live along the country's shores. But while humans need to make a plane ride or at least a car trip to escape the heat, the turtles' plan is simpler - they swim into deeper, cooler waters.

The trend is becoming apparent in a study that examines the migration patterns of female Hawksbill turtles in the UAE, Oman, Qatar, Saudi Arabia and Iran.

The project started in spring 2010 when conservationists from the Emirates Wildlife Society - World Wide Fund for Nature (EWS-WWF) attached satellite transmitters to 20 turtles from the region. The effort continued last year and resumed last week in Oman.

This week, conservationists are tagging sea turtles in Sharjah. The devices track the turtles' whereabouts, including where they feed, where they lay their eggs, and where they go after laying their eggs.

"I do not think when we started this we ever expected to get the results we did," said Dr Nicolas Pilcher, research partner on the project and founder of the Marine Research Foundation in Malaysia.

Over the past two years, the scientists attached satellite tags to female Hawksbill turtles, arriving on secluded beaches to lay their eggs. The devices reported the turtles' whereabouts every time they came to the surface to breathe. The signals showed the team where the turtles were going after laying their eggs, indicating the location of vital feeding grounds.

Dr Pilcher identified these locations by studying some 18,000 location data points, showing where the turtles have been. He noticed the turtles' preference for certain locations - healthy coral reefs providing a steady supply of sea sponges and jellyfish for the turtles to feed on.

This in itself was not surprising as the goal of the project was to find the location of the key feeding grounds. However, when Dr Pilcher compared the turtles' movement on a monthly basis, he saw that they were moving into the deeper waters as summer progressed. They were heading for the cooler waters in August and returning closer to shore in September.

"Nearly every animal did this," he said. "We managed to link it to temperature.

"Keep in mind that these are cold-blooded animals...half a degree can make a difference," said Dr Pilcher, who is also co-chair of the marine turtle specialist group, a global team of scientists who are part of the reputed International Union for the Conservation of Nature (IUCN).

More details are likely to emerge as the data is further analysed and more turtles are fitted with transmitters this spring.

Tomorrow, the team will leave for Sharjah's protected Sir Bu Nair island with trips to Iran, Qatar and Abu Dhabi's Jarnein island pending this week and next. Altogether, 31 turtles will be tagged this year, bringing to 75 the number of animals supplying data to the project.