Pacific ridley turtle (olive ridley)
Hatchling. ©Dr M. Guinea
Common name: Pacific ridley, Olive ridley turtle
Scientific name: Lepidochelys olivacea
Conservation status: The Pacific ridley turtle is 'Endangered' in Queensland (Nature Conservation Act 1992) and 'Endangered' nationally (Environment Protection and Biodiversity Conservation Act 1999).
Description: Pacific ridleys are grey or olive-grey above, usually without any conspicuous markings and whitish below. Their head is large and massive. The carapace (shell) is broad and heart-shaped, usually with six or more costal scales. They can grow to a total length of 1.5 metres. Their hatchlings are blackish above, dark brown below.
Habitat and distribution: Pacific ridleys occur in shallow, protected waters, especially in soft-bottomed habitats. They are pantropical in distribution but rarely found around oceanic islands. Major breeding aggregations occur in Mexico, the west coast of Costa Rica, in Surinam, and the east coast of India. In Australia, they occur along the coast from southern Queensland and the Great Barrier Reef, northwards to Torres Strait, the Gulf of Papua, Gulf of Carpentaria, Arafura Sea and Joseph Bonaparte Gulf in Western Australia. Low density nesting has been recorded at a limited number of sites over recent decades. Within Queensland, breeding is known only from isolated nestings at five locations within the Gulf of Carpentaria: Crab Island, Edward River, north of Weipa, Scrutten River mouth and the Wellesley Islands.
Behaviour and life history: No large rookeries of Pacific ridleys have been recorded in Australia. Pacific ridleys nest all year round, although most nesting occurs during the dry season from April to November. Females lay on average about 109 large round, parchment-shelled eggs. Hatchlings emerge from the nests about two months after laying.
Sub-adult. ©Col Limpus
Threatening processes: 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, seagrass beds, mangrove forests and nesting beaches. Other threats include accidental drowning in fishing gear and, over-harvesting of turtles and eggs.
Recovery actions:
- To conserve current populations it is also imperative that major existing feeding and nesting sites are protected so that urban and industrial development can no longer threaten them;
- The control of feral animals and domestic dogs is essential at nesting sites along Queensland's coast to protect eggs from predation;
- Increase public awareness about the effect of light sources around nesting sites and promote the use of alternative lighting and protection of nesting sites to local councils;
- 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 be done to help this species?
You can help this species by:
- remembering that rubbish you throw away can find its way to the sea, where turtles can mistake things such as plastic bags for jellyfish. Plastic swallowed by mistake can cause blockages of the stomach and intestines of marine animals such as turtles;
- 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;
- following the regulations relating to Personal Water Craft (jet skis, waveriders and waverunners), avoiding travelling over seagrass beds and shallow water, staying in the navigation channel when travelling in conservation zones and operating off the plane in "turtle and dugong go-slow areas".
Further information:
Turtle watching
Department of the Environment and Heritage. 2005. Protected marine species identification guide (PDF)* . Department of the Environment and Heritage, Canberra.
Environment Australia and Marine Turtle Recovery Team 2003. Recovery plan for marine turtles in Australia. Department of Environment and Heritage, Canberra.
Department of the Environment and Heritage 2005. Protected marine species identification guide (PDF)*. Department of the Environment and Heritage, Canberra.
Carpentaria Ghost Net Programme
* Requires Acrobat Reader
Last updated: 05 October 2007