Deborah Smith: AFTER surviving for more than 100 million years, the world’s largest sea turtle has been placed on the national threatened species. Leatherback turtles, which are found in waters off NSW as well as south Queensland and Western Australia, can grow up to 1.6 metres in length and 700 kilograms. The Environment Minister, Peter Garrett, said yesterday that the turtles, which had previously been classified as vulnerable, were now considered an endangered species. “The …