Natator depressus

Conservation status

International: ‘Data Deficient’ [World Conservation Union] (formerly listed as ‘Vulnerable’)

Australia – National: ‘Vulnerable’ [Environmental Protection & Biodiversity Conservation Act 1999]

Australia – Queensland: ‘Vulnerable’ [Nature Conservation Act 1992]

Australia - Western Australia : ‘Vulnerable’ [Wildlife Conservation Act 1950]

Description

Adults: Distinct low-domed flat carapace, with upturned edges and covered in skin; olive grey flippers and head; white plastron; carapace ~ 0.9 m

Hatchlings: Grey carapace; white plastron

Distribution and habitat

As far as we know, Flatback Turtles are only found on the continental shelf of Australia. They prefer shallow, subtidal, soft littoral seabed habitats away from reefs. They feed mainly inshore of the outer Great Barrier Reef, from Hervey Bay to the Torres Strait; the Gulf of Carpentaria; the NW shelf; the Arafura Sea and the Gulf of Papua. Hatchlings are unique in not having an oceanic pelagic phase.

Flatback Turtles swim up to 1300 kms between foraging areas in Indonesia and nesting areas in Australia.

Diet

Flatback Turtles are carnivorous, feeding mainly on benthic soft-bodied invertebrates (soft corals, sea pens, holothurians) and jellyfish.

Breeding

Nesting season – Australia: Between late November and early February. Hatchlings emerge from late December to early April.

Years between breeding 1-3 years

Average clutch size ~55 eggs

Average hatching success ~80%

Native predators on hatchlings Pelicans, ghost crabs, crocodiles, sharks.

Breeding areas – Australia:

As far as we know, Flatback Turtles nest only in Australia. There are t hree major breeding areas:

• Great Barrier Reef – on inshore islands and mainland from Bundaberg to Mackay; 4 major rookeries on the inner shelf of the Great Barrier Reef at Peak, Wild Duck, Avoid and Curtis Islands.
• Northern Great Barrier Reef and Torres Strait - low density nesting on many mainland beaches and offshore islands in the northern Great Barrier Reef, with the largest concentration on Crab Island in the western Torres Strait.
• Western Australia - the Kimberley region.

Main threats

Incidental capture in fishing and shark control program gear; coastal development; ingestion of synthetic material; boat strike; predation of eggs or hatchlings; increased incidence of disease.

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