Dermochelys coriacea – leatherback turtle
Dermochelys coriacea (Vandelli, 1761)
Family: Dermochelidae
The leatherback turtle is the largest of all the marine turtles and can grow up to nearly 3m long and weigh 900kg. It migrates huge distances between its feeding grounds and the tropical beaches where it lays its eggs.
All seven species of marine turtle are endangered. The number of breeding marine turtles is dangerously low worldwide and international trade in turtles and turtle products is banned.
In brief
- Occasionally seen off the coast of Northern Ireland
- Found in the open sea
- Most likely to be seen from July to September
- Listed as a UK Priority Species
- Threatened by entanglement in fishing equipment and turtle egg harvesting.
Species description
Adult leatherback turtles usually measure between 1.3 and 1.6m and weigh between 300 and 600kg. The shell or carapace is made up of thousands of tiny bony plates covered with smooth leathery skin – seven raised ridges run the length of the carapace from head to tail. The overall surface colour is black/grey – the underside is white with black patches. Turtles do not have teeth – leatherback turtles have backward pointing spines inside their throats that help them to feed on jellyfish.
Life cycle
Leatherback turtles are strong swimmers and spend all their lives in the open ocean – they only come ashore to lay their eggs. Females dig nests on warm tropical sandy beaches and lay 4 to 10 clutches of around 100 eggs every few years. The temperature of the nest affects the sex of the hatchlings – hot nests above 29.5 °C produce females and cooler nests below 29.5 °C produce males.
It has recently been discovered that leatherback turtles have a higher internal body temperature than their surroundings. This allows them to survive in cold northerly seas and to dive to depths of 1000m in search of the jellyfish and squid on which they feed. Little is known about the life expectancy of these animals.
Similar species
None
How to see this species
Leatherback turtles are rarely seen in Northern Ireland waters. They would be most likely to be seen from July to September.
Current status
Sea turtles are not protected in Northern Ireland waters, but are protected in general by the following:
- Classified as Critically Endangered on the IUCN Red List 2002.
- Listed in Appendix I of CITES
- Listed in Appendix I and II of the Convention on Migratory Species (CMS or the Bonn Convention)
- Listed in Appendix II of the Bern Convention
- Listed in Annex IV of the EC Habitats directive.
Why is this species a priority in Northern Ireland?
- Listed as a UK Priority Species.
Threats/Causes of decline
- Harvesting of sea turtle eggs
- Coastal development and disturbance at nesting sites
- Entanglement in fishing equipment
- Eating marine debris – plastic bags and other marine debris may be mistaken for the turtles’ natural food, jellyfish, that can cause blockages in the gut and, eventually, death.
Conservation of this species
Current action
Leatherback turtles are included in the UK Grouped Species Action Plan for marine turtles which was published in 1999.
- Records of all strandings and sightings of marine turtles in Northern Ireland are collated by CEDaR
- A 'Turtle Code' advice sheet was produced by the Nature Conservancy Council in 1988, aimed at the fishing industry and providing advice on identification, legislation, record submission and dealing with entanglements.
Proposed objectives/actions
- Avoid accidental harm to, and by-catch of, marine turtles when present in Northern Ireland waters.
- Contribute to international measures for the conservation of marine turtles.
What you can do
To report turtle sightings, contact CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU, Tel: 028 9039 5264, cedar.info [at] nmni.com.
Further information
Links
Grouped Species Action Plan for Marine Turtles
Northern Ireland's Mammals, Amphibians & Reptiles
Literature
Text written by:
Angela Ross, Curator of Vertebrates, Ulster Museum
iNaturalist: Species account : iNaturalist World Species Observations database