Single calves are born at intervals of 1 to 3 years. Each measures about 5m and weighs about 1 tonne. Turtles Six species of sea turtle are present in Australian waters. Green turtles are most commonly seen around the Whitsunday islands. They grow to about 1m in length, can weigh 150kg or more and are vegetarian, feeding on sea grass and algae.
Green turtles have two main nesting areas.
One in the Capricorn Bunker group of islands in the southern Great Barrier Reef, the other at the opposite end of the reef at Raine Island and nearby cays. Unlike the all in one spawning exhibited by other reef organisms, reproduction in reef turtles is usually divided into mating and nesting, which take place in different specific locations. With most sea turtles, mating occurs from October to November each year, either inshore near estuaries or offshore in the lagoons of coral cays and continental islands. Because female turtles mate with a number of turtles and store sperm, a great amount of genetic mixing occurs. After mating is finished, the male turtle returns to his usual year round habitat and the female turtle moves to the nesting area.