Lepidochelys olivacea

La 2ème réunion du Groupe de travail sur les tortues marines du nord de l’océan Indien, mis en place par le MdE de la CMS sur les tortues marines de la région IOSEA, s’est tenue les 29 et 30 janvier et était organisée par le Ministère de la conservation des espèces sauvages du Sri Lanka, à Colombo. Ouverte par le Secrétaire Douglas Nanayakkara, du Ministère du Développement durable et des espèces sauvages, le principal objectif de la réunion était de trouver un accord sur des actions régionales concertées afin de conserver les tortues marines.

30 Jan 2018
Description: 

The olive ridley turtle (Lepidochelys olivacea) is considered the most abundant sea turtle in the world, with an estimated 800,000 nesting females annually. Adults are relatively small, weighing on average around 45 kg. As with other species, their size and morphology varies from region to region. The olive ridley is omnivorous, feeding on algae, lobsters, crabs, tunicates, mollusks, shrimp, and fish.

The olive ridley is globally distributed in the tropical regions of the South Atlantic, Pacific, and Indian Oceans. It is mainly a pelagic species, but it has been known to inhabit coastal areas, including bays and estuaries; where they can dive to depths of about 150 m to forage on benthic invertebrates. Olive ridleys often migrate great distances between feeding and breeding grounds. They mostly breed annually, involving an annual migration from pelagic foraging, to coastal breeding and nesting grounds, back to pelagic foraging. Olive ridleys reach sexual maturity in around 15 years, a young age compared to some other sea turtle species. Many females nest every year, once or twice a season, laying clutches of approximately 100 eggs.

In certain places, the olive ridley has one of the most extraordinary nesting habits in the natural world. Large groups of turtles gather off shore of nesting beaches. Then, all at once, vast numbers of turtles come ashore and nest in what is known as an "arribada". During these arribadas, hundreds to thousands of females come ashore to lay their eggs. In the northern Indian Ocean, arribadas occur on three different beaches along the coast of Orissa, India. Gahirmatha used to be one of the largest arribada nesting sites in the world. However, arribada nesting events have been less frequent there in recent years and the average size of nesting females has been smaller, indicative of a declining population. Declines in solitary nesting of olive ridleys have been recorded in Bangladesh, Myanmar, Malaysia, and Pakistan. In particular, the number of nests in Terengganu, Malaysia has declined from thousands of nests to just a few dozen per year. Solitary nesting also occurs extensively throughout this species' range.

Despite the enormous numbers of olive ridleys that nest in Orissa, India, this species is not generally common throughout much of the Indian Ocean. Its pelagic habits make it especially subject to interactions with modern fisheries, such as longlines. Coastal trawl and net fisheries are also important sources of incidental catch and mortality.

The preceding biological information on marine turtle species found around the Indian Ocean is derived partly from the NOAA Fisheries, Office of Protected Resources, website:(http://www.nmfs.noaa.gov/pr/species/turtles/), supplemented by other sources (such as a website of the Australian Government, Department of Environment, Water, Heritage and the Arts -- for information on the Flatback turtle), and additional information supplied by Dr. Jack Frazier (IOSEA Advisory Committee Chair). 

 

Information d'évaluation
Instruments de la CMSCMS, IOSEA Marine Turtles, Atlantic Turtles
IUCN StatusVulnerable
Date of entry in Appendix I1985
Date d'inscription à l'Annexe II1979
Répartition géographique
Pays Angola, Antigua and Barbuda, Australia, Bahrain, Bangladesh, Barbados, Benin, Brazil, Brunei Darussalam, Cabo Verde, Cambodia, Cameroon, Canada, Chile, China, Colombia, Comoros, Congo (Brazzaville), Costa Rica, Cuba, Côte d'Ivoire, Democratic People's Republic of Korea, Democratic Republic of the Congo (Kinshasa), Djibouti, Dominica, Dominican Republic, Ecuador, Egypt, El Salvador, Equatorial Guinea, Eritrea, France, Gabon, Gambia, Ghana, Grenada, Guatemala, Guinea, Guinea-Bissau, Guyana, Haiti, Honduras, India, Indonesia, Iran, Iraq, Israel, Jamaica, Japan, Kenya, Kuwait, Liberia, Madagascar, Malaysia, Maldives, Mauritania, Mexico, Mozambique, Myanmar, New Zealand, Nicaragua, Nigeria, Oman, Pakistan, Panama, Papua New Guinea, Peru, Philippines, Qatar, Republic of Korea, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Saudi Arabia, Senegal, Seychelles, Sierra Leone, Singapore, Solomon Islands, Somalia, South Africa, Sri Lanka, Sudan, Suriname, Thailand, Togo, Trinidad and Tobago, United Arab Emirates, United Republic of Tanzania, United States of America, Venezuela, Viet Nam, Yemen
Noms communs
AnglaisRidley Turtle, Olive Ridley Turtle
FrançaisTortue Batarde
EspagnolTortuga olivácea
AllemandBastardschildkröte
Taxonomie
ClasseReptilia
OrdreTestudinata
FamilleCheloniidae
Nom scientifique Lepidochelys olivacea
Author(Eschscholtz, 1829)
Standard referenceEckert, K.L., Bjorndal, K.A., Abreu-Grobois, F.A. and Donnelly, M. (Eds) (1999). Research and management techniques for the conservation of sea turtles. IUCN/SSC Marine Turtle Specialist Group Publication No.4.

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Other details
Additional notesAll migratory Cheloniidae spp.

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