Definitions

Pacific ridley

Olive Ridley

[rid-lee]
Also see: Kemp's Ridley turtle.

The Olive Ridley (Lepidochelys olivacea), also known as the Pacific Ridley, is one of the smallest species of sea turtle. It is named for the olive color of its heart-shaped shell.

Anatomy and morphology

These lightly-built turtles have an average weight just over 100 lb (up to 50 kg.). They have a high-domed shell, with a carapace length of only 30 inches (70 cm). The carapace is made up of five pairs of costal scutes, with occurrences of up to 6 to 9 divisions per side. The margins are smooth. The carapace is a dark olive green in color with a yellowish underside. The head is large.

Distribution

It is usually found in the Indo-Pacific and Atlantic oceans. The common name in Spanish is tortuga golfina o del golfo.

The beaches of Orissa, India provide one of the last nesting grounds of the Olive Ridley turtles in the world. In addition, trawling and offshore drilling for oil and gas has been blamed for the death of more than 20 Olive Ridley turtles, which have washed ashore in the last ten years.

Though listed by the US Endangered Species Act, populations in the Atlantic Ocean continue to dwindle, while the populations found in areas around the Pacific Ocean seem to be on the rise. Furthermore, their ability to reproduce in the Red Sea was thought impossible, however, recent evidence suggests that they do indeed hatch in Eritrea amongst other places in the Red Sea.

In the Indian Ocean, a major nesting ground for the species can be found in the Indian state of Orissa. Beaches in Devi, Gahirmatha and Rushikulya are known nesting sites for the L. olivacea Indian Ocean population. In 2007, around 130,000 turtles nested on the beaches of Gahirmatha. They are common in the Bay of Bengal, seen especially along parts of the Tamil Nadu coastline, including within the main city, Chennai. Olive Ridleys are seen frequently in laying eggs in the shore of Saint Martin's Island in Bangladesh.

The villagers of Kolavipalam in Kozhikkode (Calicut) district have been burning midnight oil to ensure the survival of the visiting Olive Ridley turtles. Every year, the turtles come to nest in the 20-km beach, which stretches between Pavyoli and Kottapuzha estuary, some 45 km north of Calicut. But till 1992, the eggs mostly fell prey to stray dogs, jackals and humans, too, till a few youngsters started observing the turtles and reading about them. After learning that they were the Olive Ridley turtles (Lepidochelys olivacea), they started guarding turtle nests day and night.

A network of volunteers runs Turtle Walks during the main nesting season in Chennai, which runs from January to March. Nesting turtles that are found are protected from the dogs, and the nests dug up after & relocated to a hatchery. This saves the eggs from predation from dogs, crabs, seagulls, etc. Once the hatchlings emerge, volunteers again help steer the little ones towards the beckoning waves of the Bay of Bengal.

It is believed that Olive Ridley turtles return to nest on the same beach they are hatched. If this is the case, then on these beaches where efforts are made to protect the eggs and hatchlings there should be rises in the numbers returning to nest in future.

Ecology and life history

Olive Ridleys are omnivorous, feeding on crabs, shrimp, rock lobsters, sea grasses, algae, snails, fish, sessile, pelagic tunocates and small invertebrates. They are sometimes seen feeding on jellyfish in shallow waters. These turtles forage offshore in surface waters and can dive to depths of at least 150 meters (500 feet).

Conservation

Threats

Commercial trawling has been shown to disrupt and kill Olive Ridleys in India. The turtles are caught in the trawler's nets being dragged far behind the boats. Unable to surface, the turtles suffocate and drown. Some other threats are the poaching of turtle eggs, construction on beaches, and pollution. Mega ports being built by Tata Steel, POSCO and other companies as well as oil exploration activities offshore pose serious long term threats to the species along the Orissa coast, India.

The threat perception to turtle habitat with regard to the TATA Steel port (Dhamra port) has to be seen in light of research studies which show that the port site is not frequented by nesting turtles. (Pandav et al., 1994) (Pandav & Choudhury, 2000)The port project has got the due environmental clearances from the central govt of India. In addition the threat perception from this port was further scrutinized in the year 2000 by the National Environment Appellate Authority, mandated specifically to examine environmental clearances, who upheld the environment clearance to the proposed port. The port is fully committed to the cause of the environment and are associating with the best wildlife conservation organization to safe guard the interests of wildlife and wildlife habitat. Further this is not a TATA Steel port but actually an infrastructure project which is being built by the dhamra port company ltd (A Special Purpose Vehicle created by a concession agreement between the state govt and L & T and TATA Steel [the private partners]), this port would eventually revert to the State govt which will own the port.

However, a number of national and international environmental groups have expressed concern over the fact that the port, by virtue of its proximity to two Protected Areas, poses an unacceptable environmental risk. Greenpeace has released a critique that exposes serious and fundamental flaws in the Environment Impact Assessment (EIA) conducted for TATA’s Dhamra port project in Bhadrak district, Orissa. The critique has been authored by Dr. Paul Johnston and Dr. David Santillo from the Greenpeace Research Laboratories, School of Biosciences, Exeter University, United Kingdom. The port is less than 5 kilometres from the Bhitarkanika Sanctuary, India's second largest mangrove forest, and less than 15 km. from the turtle nesting beaches at Gahirmatha Sanctuary. There is also evidence of the presence of turtles in the offshore waters adjoining the port site. The environmental concerns surrounding the port do not stop at turtles. The port site itself is also a breeding ground for horse-shoe crabs, as well as rare species of reptiles and amphibians. One such species, the amphibian Fejervarya cancrivora, is the first record for the Indian mainland.

Status

It is listed as Vulnerable on the IUCN Red List; and Endangered under both Australia's Environment Protection and Biodiversity Conservation Act 1999 and Queensland's Nature Conservation Act 1992.

See also

Notes

References

  • Pandav, B., Choudhury, B.C. and Kar, C.S. (1994) : A Status survey of Olive Ridley Sea Turtle and their nesting beaches along the Orissa Coast, India. Report published by the Wildlife Institute of India.
  • Pandav, B and B.C. Choudhury (2000): Conservation and management of olive ridley sea turtle (Lepidochelys olivacea) in Orissa. Final Report. Wildlife Institute of India.
  • Database entry includes a lengthy justification of why this species is endangered

External links

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