Olive Ridley turtle

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Olive Ridley turtles are an endangered species of marine sea turtles. These olive green turtles are the smallest of the marine turtle species in the world. They are named after H.N. Ridley FRS, who first reported the sighting of these turtles in Brazil in 1887.

There are evidences of Olive Ridley turtles being killed in in large numbers for their meat and leathers for centuries. Olive Ridley turtles have yet to recover from centuries of over-exploitation.


[edit] Why should I be aware of this

  • Olive Ridley turtles turtles are an endangered species. The decline in their numbers is primarily due to human activities such as the direct harvest of adults and eggs; and loss of nesting habitats and unintentional capture by commercial fisheries.
  • The number of important breeding sites is very restricted. So efforts to protect their major beaches are vital.
  • Despite conservation efforts, the illegal harvest of the eggs in the Central American region continues. There is also high mortality of adults due to coastal fisheries that do not yet use Turtle Excluder Devices (TEDs) in their nets.
  • The coast of Orissa (India), the largest of only three nesting sites for the Olive Ridley in the world, there are plans to construct a deep water port. The increased shipping traffic might deter the turtles from coming in from the sea to mate and nest. Moreover, the dredging, oil spills and chemical leaks might make the water toxic for the turtles. It is feared that the Olive Ridley turtles will not be able to adapt to these new threats quickly enough to shift the arribada to a safer and more suitable location.
  • The highly migratory behavior of Olive Ridley turtles makes them shared resources among many nations. Therefore, conservation efforts for Olive Ridley populations in one country may be jeopardized by activities in another.

[edit] All about Olive Ridley Turtle

Olive Ridley turtles are very small in size. They grow to an average of 70 cms. Adults weigh approximately 45 kgs. They can dive to great depths and may be bottom feeders. They are highly migratory, covering thousands of kilometers between foraging and nesting grounds.

The Olive Ridley is mostly carnivorous, feeding on such creatures as jellyfish, snails, crabs, and shrimp. They occasionally eat algae and seaweed as well. Hatchlings, most of which perish before reaching the ocean, are preyed on by crabs, raccoons, pigs, snakes, and birds, among others. Adults are often taken by sharks.

[edit] Nesting habits of Olive Ridley turtles

The Olive Ridley turtles display a distinct mass nesting habit. Large groups of turtles gather off shore of nesting beaches. Then, all at once, vast numbers of turtles come ashore and nest. This is also called ‘arribada’, which means mass arrival in Spanish. It is believed that Olive Ridley turtles return to nest on the same beach they are hatched. Keeping this in mind, conservation efforts are directed at beaches where the turtles have been nesting in the past.

The turtles choose narrow beaches near estuaries and bays to lay eggs. Each adult female lays approximately 100-140 eggs at a time. It is believed that they nest in an interval of one-four years. The nesting season is November to March.

Olive ridleys have nesting sites all over the world, on tropical and subtropical beaches. During nesting, they use the wind and the tide to help them reach the beach.

[edit] Olive Ridley turtles in India

In India, mass nesting takes place along the east coast state of Orissa at three nesting grounds -- Gahirimatha, Devi river mouth and Rushikulya river mouth. In 2004, over one million turtles came to the Orissa shores to dig pits and lay eggs, the largest concentration being at Gohirmatha beach. Such large concentrations only occur at a few sites in the world.

Olive Ridleys also nest sporadically along the coastline of India. In West Coast, nesting beaches in Gujarat are Gulf of Kutch (Jamnagar with the maximum number of nest) and Gulf of Khambhat (Bhavnagar being a major nesting ground). In Maharashtra Olive Ridleys have been reported nesting near Gorai, Kihim, Manowrie, Versova and the beach between Ambolgad and Vetye in the Ratnagiri district. There are two beaches in Goa namely Morjim and Galgibag; and Kozhikode district (Calicut) in Kerala which are frequented by these turtles for nesting. Sporadic nesting has been recorded in Tamil Nadu, Andhra Pradesh, and in Sundarbans in West Bengal.

In 2007, the Olive Ridley turtles did not appear at the sandy nesting grounds near the Rushikulya River in Ganjam district. They did make an appearance in 2008.

[edit] Endangered status of Olive Ridleys turles

The Olive Ridley turtle has been declared either an endangered species or a threatened species across the world. Its numbers are fast dwindling. Rough estimates put the worldwide population of nesting females at about 800,000, but its numbers, particularly in the western Atlantic have declined precipitously.

The Olive Ridley is listed as endangered by the World Conservation Union (IUCN). According to the Marine Turtle Specialist Group (MTSG) of the IUCN, there has been a 50% reduction in population size since the 1960s. Although some nesting populations have increased in the past few years, the overall reduction is greater than the overall increase.

[edit] Olive Ridley turtles and the environment

Marine turtles play an important role in marine ecosystems. Olive Ridley turtles feed on invertebrates and important to both open ocean and coastal ecosystems.

[edit] CopperBytes

  • On Rushikulya Beach in India, an estimated 200,000 turtles nested during a single arribada.
  • In some Asian and African societies, sea turtles are considered sacred and killing one is forbidden.
  • Male Olive Ridley turtles can be distinguished from females by their tails, which stick out beyond their carapace.
  • Olive Ridley turtles are the smallest of all the marine turtles and their shell is shaped like a heart.
  • There are many theories on what triggers an arribada, including offshore winds, lunar cycles, and the release of pheromones by females. Despite these theories, scientists have yet to determine the actual cues for Ridley arribadas.
  • Olive Ridley turtles often migrate great distances between feeding and breeding grounds. Two separate satellite studies showed both male and female Olive Ridleys leaving the breeding and nesting grounds off the Pacific coast of Costa Rica and migrating to the deep waters of the Pacific Ocean.

[edit] References

  • Olive Ridley Turtle: WWF India
  • Endangered Olive Ridley Turtles: The WILD Foundation
  • Olive Ridley Sea Turtle: National Geographic
  • Once slaughtered in the hundreds of thousands... WWF
  • Great Barrier Reef Marine Turtles
  • Olive Ridley Sea Turtle US Fish & Wildlife Services
  • Mass nesting of endangered Olive Ridley turtles starts in Orissa
  • Olive Ridley Turtle