Hawksbill turtle Photo:EHP
Common name: hawksbill turtle
Scientific name: Eretmochelys imbricata
Conservation status: This species is listed as Vulnerable in Queensland (Nature Conservation Act 1992) and nationally (Environment Protection and Biodiversity Conservation Act 1999). It is ranked as a critical priority under the Department of Environment and Heritage Protection Back on Track species prioritisation framework.
Hawksbill turtle Photo:EHP
The hawksbill turtle is olive-green or brown above, richly variegated with reddish-brown, dark brown and black. The scales of head and face are often dark with pale contrasting sutures (lines between the scales) and it is cream to yellowish below (the plastron). Hawksbill turtle hatchlings are a brown-black colour. There are four costal scales on each side of the shell (refer to the Protected Marine Species Identification guide - hawksbill turtle). The adult females' average carapace (shell) length is 82 cm and weight is 50 kg. The hawksbill turtle has a distinctive parrot-like beak.
Habitat and distribution
The hawksbill turtle forages over coral reefs, rock outcroppings, and seagrass beds. In Australia the hawksbill turtle is found along the tropical coasts of northern and eastern Australia, from mid-western Western Australia to southern Queensland. The main feeding area extends along the east coast, including the Great Barrier Reef. Other feeding areas include Torres Strait and the archipelagos of the Northern Territory and Western Australia, possibly as far south as Shark Bay or beyond.
Australia has some of the largest remaining nesting populations of hawksbill turtles. Approximately 6000-8000 nest on the Great Barrier Reef. It is estimated that populations nesting in the Torres Strait are declining every year. Worldwide it is estimated that the hawksbill population has declined by 80 per cent from one century ago and further losses would have occurred prior to that time.
Life history and behaviour
Hawksbill turtles have a sharp pointy beak that they use to pick sponges out of cracks and crevices in coral reefs. They mature slowly and may not reach reproductive age until 30 years. Females lay between one to six clutches per season with an average of 122 eggs. Females will only nest every two to four years. After the hatchlings emerge from the nest they swim for several days out into the sea. They then spend approximately five to 10 years drifting in the ocean and return to the coastal areas of Australia at about 38 cm long.
Diet: The majority of their diet consists of sponges, although they also feed on seagrasses, algae, soft corals and shellfish.
All marine turtle species are experiencing serious threats to their survival. The main threats are pollution and changes to important turtle habitats, especially coral reefs, mangrove forests and nesting beaches. Other threats include accidental drowning in fishing gear and over-harvesting of turtles and eggs.
The hawksbill turtle is prized for the scales of its carapace (shell). All around the world jewellery and ornaments have been made out of 'tortoiseshell'. For this reason hawksbill turtles have almost been hunted to extinction in many countries. Trade of tortoiseshell is now banned internationally, however some illegal trade still occurs. Some Australian nesting and feeding populations may be threatened by harvest for meat and the tortoiseshell trade in neighbouring countries, particularly Papua New Guinea and the Solomon Islands.
- To conserve current populations it is imperative that major existing feeding and nesting sites are protected.
- The control of feral pigs, foxes and wild dogs is essential at nesting sites along Queensland's coast to protect eggs from predation.
- Encourage traditional hunters to comply with harvesting conditions.
- Fishing activities need to be monitored, in particular the use of Turtle Excluder Devices (TEDs) and the need for commercial fishers to check longlines, gillnets and lobster/crab pots frequently to disentangle any turtles caught accidentally.
What can you do to help this species
You can help this species by:
- remembering that rubbish you throw away can find its way to the sea. Plastic debris that is swallowed by mistake can cause blockages of the stomach and intestines of marine animals such as turtles; and
- being on the lookout to avoid turtles when out in your boat. Many turtles are struck by propellers of speeding boats and this can cause injury and death.
- Environment Australia and Marine Turtle Recovery Team 2003. Recovery plan for marine turtles in Australia. Department of the Environment and Heritage, Canberra.
- Department of the Environment and Heritage 2005. Protected marine species identification guide. Department of the Environment and Heritage, Canberra.
- Department of Sustainability, Environment, Water, Population and Communities. 2012. Eretmochelys imbricata, hawskbill turtle: in the Species Profile and Threats Database.
- Carpentaria Ghost Nets Programme
- Spotila, JR 2004. Sea turtles. The John Hopkins University Press, London.
- Boat strike impact on turtle and dugong in Moreton Bay
- Turtle watching