Coastal water feeding area

Most species of sea turtle do not become sexually mature until they are between 20 and 50 years old. So much of their juvenile and adult lives are spent in coastal feeding areas.

Breeding migration

Once sexually mature, adult males and females migrate towards the area where they hatched. This migration can often be thousands of kilometres.

Mating

Mating occurs just offshore from the nesting beaches and females mate with a number of different males. They store the sperm to fertilise several clutches of eggs that they will lay in the course of the nesting season.

Males return to feeding area

Once the females begin to nest, the males return to their feeding areas.

Nesting beach

Females crawl out of the water, generally at night, to dig a nest and lay their eggs. This process is repeated every few weeks and, depending on the species, a female may lay as many as 7 clutches of eggs.

Females first look for a suitable site and then dig a body pit with their front flippers. They then excavate an egg chamber with their hind flippers. They may repeat this process several times until they are satisfied that the nesting conditions are correct, at which point they will lay a clutch of eggs. Between 50 and 130 eggs are laid, depending on the species.

The females then fill in the nest with sand and return to the water, where they begin the fertilisation process again with sperm that they have previously stored.

Females return to feeding area

After the nesting season is over, females return to their foraging grounds and depending on how plentiful their food supply is they may not breed again for several years.

Hatching

Depending upon the species and environmental conditions, the eggs hatch after 7-12 weeks. Sand temperature determines the sex of the turtle. Warmer temperatures produce females and cooler ones, males.

The hatchlings emerge from their eggs and make their way upwards where they wait just under the sand surface for nightfall. They then all emerge together and make their way to the sea using the lowest light horizon to find their way.

Once in the water we believe they use the currents, waves and the Earth’s magnetic fields as cues to take them towards deeper offshore waters.

Open-ocean feeding area ‘the lost years’

Hatchlings enter a phase known as ‘the lost years’ where little is known about their movements. They are thought to spend time feeding in oceanic areas where flotsam attracts a plentiful food supply.

Enter coastal feeding area

Older hatchlings do not appear to join the juveniles and adults at the coastal feeding areas until they are about 5-10 years old and have reached about 30 centimetres in length.

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