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Flatback Turtle (Natator depressus)

The Flatback Turtle is a marine turtle that nests only in northern Australia. It occurs in northern coastal waters, especially shallow, soft-bottomed areas close to shore and away from reefs, which are important habitats to consider during works.

Conservation status

Commonwealth, EPBC Act 1999: Vulnerable.

Queensland, Nature Conservation Act 1992: Vulnerable.

Western Australia, Biodiversity Conservation Act 2016: Vulnerable.

Commonwealth, EPBC Act 1999: Listed migratory. Listed migratory species are a matter of national environmental significance, so a significant impact needs referral.

Commonwealth, EPBC Act 1999: Listed marine. A listed marine species under Part 13 of the EPBC Act. Killing, injuring, taking or moving it in a Commonwealth area needs a permit.

Seasonal planning

Nesting occurs year-round in parts of the Gulf of Carpentaria and Northern Territory, while elsewhere it is seasonal, generally from October to March.

Seasonal evidence: From published sources for this species.

Timing varies between sites and years.

  • Nesting season: Nesting occurs year-round in parts of the Gulf of Carpentaria and Northern Territory, while elsewhere it is seasonal, generally from October to March.

Identification: Appearance

Adults have a broadly oval, relatively flat shell with upturned lateral edges. They have four costal shields on each side and three postocular scales.

Adults have a broadly oval, relatively flat shell with upturned lateral edges. They have four costal shields on each side and three postocular scales.

Identification: Confirming identity

Confirm the identity of any suspected record with a specialist and a photograph or voucher, as required by the relevant permit.

Distribution: Known range

In Australia, Flatback Turtles occur from the Kimberley region of Western Australia through the Northern Territory to Queensland, extending south to the Tropic of Capricorn. They are occasional visitors to northern New South Wales, and feeding grounds also extend to Indonesia and Papua New Guinea.

In Australia, Flatback Turtles occur from the Kimberley region of Western Australia through the Northern Territory to Queensland, extending south to the Tropic of Capricorn. They are occasional visitors to northern New South Wales, and feeding grounds also extend to Indonesia and Papua New Guinea.

Distribution: National mapping

The Commonwealth species distribution model (SNES) maps where the species or its habitat is known, likely or may occur. Use it with local records and site inspection.

Habitat: Habitat

Adults use shallow, soft-bottomed coastal waters, bays and areas close to shore, usually away from reefs and rarely beyond the continental shelf. Nesting occurs on sandy beaches and islands in tropical Australia.

Adults use shallow, soft-bottomed coastal waters, bays and areas close to shore, usually away from reefs and rarely beyond the continental shelf. Nesting occurs on sandy beaches and islands in tropical Australia.

Foraging habitat: Diet

Flatback Turtles are carnivorous and feed mainly on soft-bodied marine prey. Their diet includes sea cucumbers, soft corals, jellyfish, molluscs and prawns.

Flatback Turtles are carnivorous and feed mainly on soft-bodied marine prey. Their diet includes sea cucumbers, soft corals, jellyfish, molluscs and prawns.

Breeding habitat: Breeding

All known breeding sites are in Australia, on beaches and islands in Queensland, the Northern Territory and Western Australia. Nesting beaches include open mainland beaches and inshore continental islands.

All known breeding sites are in Australia, on beaches and islands in Queensland, the Northern Territory and Western Australia. Nesting beaches include open mainland beaches and inshore continental islands.

Sheltering habitat: Shelter

Not documented in the published sources used for this profile.

Not documented in the published sources used for this profile.

Threats: Threats

Not documented in the published sources used for this profile.

Not documented in the published sources used for this profile.

Threats: Works risk

Works on nesting beaches that create obstructions or leave abrasive surfaces could increase the risk of turtles colliding with obstacles or being scraped. Avoiding such changes is particularly relevant at beaches used for nesting.

Survey methodology: 1. Species-specific methods

Use methods consistent with the Commonwealth survey guidelines and engage a specialist with the right permits.

Satellite tracking has been used to document movements and habitat use, including nearshore inter-nesting habitat and foraging locations.

Survey methodology: 2. Commonwealth guidance

For EPBC Act referrals, survey effort and methods should be consistent with the ePBC Act publications, including the National Guidelines for the Survey of Cetaceans, Marine Turtles and the Dugong (2024), read with the Significant impact guidelines 1.1.

Survey methodology: 3. Limits

A non-detection is not proof of absence. Match survey timing to the species and season, and record effort.

Vegetation associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific vegetation association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Ecosystem associations: Queensland RE 8.2.1: Casuarina equisetifolia low woodland and/or sparse herbland to open scrub on foredunes and beaches

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

8.2.1: Provides nesting sites for significant species including the Flat Back Turtle (Natator depressus) (Pollock, 1995), and Beach Thick Knee, both are listed as "Vulnerable" in the Queensland Nature Conservation Act 1992. Habitat for the significant species Mongolian Plover, Sooty Oystercatcher, Great Knot, Eastern Curlew, Terek Sandpiper, Bar-tailed Godwit and Ruddy Turnstones (Watkins 1993). At the southern end of the bioregion (near Yeppoon) this ecosystem is possible habitat for Paspalum batianoffii listed as "Extinct" in the Queensland Nature Conservation Act 1992.

Exact scientific-name mention in REDD special values. May describe potential habitat or a qualified association; not a verified record or preference.

Evidence: Unreviewed source mention

Confidence: Not independently verified

Region: Queensland; 8

Habitat use: general

Soil and substrate associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific soil association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Water and wetland associations

Source-checked associations and automatically indexed candidates are separated below. An association does not establish site presence, preference or dependence.

No species-specific water association has been indexed or source-checked in this evidence library. This is an evidence gap, not evidence of no association.

Fauna records and mapped habitat: Not yet analysed

Record locations can be overlaid with mapping, but record frequency alone does not measure habitat preference. No species is excluded from desktop assessments by this analysis.

No quality-controlled record-to-map analysis has been completed for this species. The existing generalised distribution dots and indicative range polygons have not been treated as precise occurrence coordinates.

A defensible run needs dated, independently attributable records, coordinate uncertainty, duplicate and captive-record checks, layer versions and regional scope. Preference and absence require additional survey-effort and detection evidence.

Habitat limitations and contrary evidence: No supported exclusion recorded

Not recorded is not the same as cannot occur. Low suitability, resident habitat, breeding habitat and occasional movement are different conclusions.

This library has not established a vegetation, ecosystem or soil-type exclusion for this species. This does not mean all habitat is suitable; the evidence needed to justify an exclusion has not been assembled.

Habitat limitations and contrary evidence: Before using a negative association

  • Confirm the taxon, geographic region, life stage and habitat function covered by the evidence.
  • Check survey methods, season, repeated effort and detectability before interpreting non-detection.
  • Investigate credible contradictory records and microhabitats absent from broad mapping.
  • Do not convert a missing map class, low record count or failed data request into species absence.

Before disturbance: 1. Desktop and approvals

Confirm whether the project could affect the species before works begin.

Check national mapping, state records and recent surveys for the site. An action likely to have a significant impact on this nationally listed species needs EPBC Act referral, and state permits apply where it is state listed.

Before disturbance: 2. Plan to avoid

Plan in-water works, vessel movements and lighting to avoid known habitat and sensitive periods, and set observer and shutdown procedures before works start.

During disturbance: 1. Controls

Keep works inside the approved footprint and conditions.

Use spotters and exclusion zones for in-water works and vessels, and pause works if the species is seen within the zone.

During disturbance: 2. Stop and report

If the species is found unexpectedly, stop work at that spot and contact the project ecologist and the relevant agency.

After disturbance: 1. Records

Record outcomes.

Record sightings, habitat lost or retained and any injury or death, and report them under the approval conditions.

Rehabilitation: 1. Restore

Restore disturbed habitat where possible.

Remove temporary structures, restore natural flow and substrate, and monitor water quality until it returns to baseline.

Sources