KARACHI, May 3: The two green turtles on which satellite transmitters were installed in September 2006 for the mapping of their movement in the Arabian Sea have gone missing, it emerged on Thursday.

The data sent in by the transmitters of the turtles, which were named Chandni III and Chandni IV, was last recorded in November 2006, sources told Dawn.

This was the second attempt by Pakistan at the mapping of the movement of the green turtles. In August 2001, two turtles, named Chandni I and Chandni II, were mounted with satellite transmitters. They went missing when shortly after the Sept 11 attacks on US soil the Arabian Sea played host to American warships launching attacks on Afghanistan.

The sources told Dawn that Chandni III and Chandni IV had been fitted with satellite transmitters by the World Wide Fund for Nature (WWF), the Environmental and Wildlife Development Agency of Abu Dhabi and the Sindh Wildlife Department at the WWF’s wetland centre in Sandspit in the first week of September 2006.

They added that the location data from the transmitters of the green sea turtles — whose scientific name is chelonia mydas — was received through Argos, a satellite-based system that collects, processes and disseminates environmental data from fixed and mobile platforms worldwide.

They explained that the transmitters were installed to send in information on the turtles’ post-nesting migration patterns, their foraging area, time spent on foraging, distance covered in a day, biological characteristics and general behaviour.

A source at the WWF said the two green turtles might have drowned or been killed by a predator.

In most cases, green sea turtles drown when they become entangled in fishing nets.

WWF chief Ali Hassan Habib told Dawn that the data received indicated that the four Chandnis came to lay eggs approximately three times in a season and then rested for a couple of years.

He explained that the peak egg-laying season continued from August to December.

He added that the four turtles came to lay eggs with a gap of two to three weeks after the transmitters had been installed on them.

He said the satellite data, as well as sightings by humans, showed that the turtles came to the beach for nesting.

The data sent in by the turtles’ transmitters was received and maintained by both WWF and the Environmental and Wildlife Development Agency of Abu Dhabi.

Mr Habib said one of the turtles fitted with transmitters in September 2006 had swum to the Indian coast of Gujarat and the other had moved to the coastal city of Gadani in Balochistan.

Dr Fahmida Firdous, a turtle expert associated with the Sindh Wildlife Department, told Dawn that Karachi’s beaches, especially Hawkesbay and Sandspit, were among the few tropical beaches in the world where green sea turtles came to lay their eggs. She added that marine turtles were in danger of extinction.

She said the survival rate of eggs laid by a turtle was 0.1 per cent.

“That is to say, only one out of 1,000 turtle eggs manage to survive not only the vagaries of the weather but also predators like stray dogs.”

Dr Firdous said the Sindh Wildlife Department was undertaking a turtle conservation project under which turtle eggs were collected, brought to the SWD enclosures and buried so that they could hatch.