Olive Ridley

Lepidochelys olivacea

Summary 3

The olive ridley sea turtle (Lepidochelys olivacea), also known as the Pacific ridley sea turtle, is a medium-sized species of sea turtle found in warm and tropical waters, primarily in the Pacific and Indian Oceans.

Diagnosis 3

Growing to about 2 feet in length, the Olive ridley gets its name from its olive colored carapace, which is heart-shaped and rounded. Males and females grow to the same size; however, females have a slightly more rounded carapace as compared to the male.[1] The heart-shaped carapace is characterized by four pairs of pore-bearing inframarginal scutes on the bridge, two pairs of prefrontals, and up to 9 lateral scutes per side. Olive ridleys are unique in that they can have variable and asymmetrical lateral scute 6 to 8 counts ranging from five to 9 plates on each side, with six to eight being most commonly observed.[2] Each side of the carapace has 12–14 marginal scutes.

The carapace is flattened dorsally and highest anterior to the bridge. It has a medium–sized, broad head that appears triangular from above. The head's concave sides are most obvious on the upper part of the short snout. It has paddle-like forelimbs, each having two anterior claws. The upperparts are grayish green to olive in color, but sometimes appear reddish due to algae growing on the carapace. The bridge and hingeless plastron of an adult varies from greenish white in younger individuals to a creamy yellow in older specimens (maximum age being up to 50 years). [2][3]

Hatchlings are dark gray with a pale yolk scar, but appear all black when wet.[2] Carapace length ranges from 37 to 50 mm. A thin, white line borders the carapace, as well as the trailing edge of the fore and hind flippers.[3] Both hatchlings and juveniles have serrated posterior marginal scutes, which become smooth with age. Juveniles also have three dorsal keels; the central longitudinal keel gives younger turtles a serrated profile, which remains until sexual maturity is reached.[2]

Conservation 4

Numbers of marine turtles are notoriously difficult to investigate given their oceanic habitat and worldwide distribution. International trade in olive ridley turtles and products is banned under their listing on Appendix I of the Convention on International Trade in Endangered Species (CITES) but a significant illegal trade (particularly in eggs) still occurs. [4] TRAFFIC (the wildlife trade monitoring arm of WWF and the IUCN) is involved in monitoring black market trade and bringing it to the attention of relevant authorities. [5] The fitting of Turtle Excluding Devices (TEDs) to shrimp-trawl nets offers an encouraging step in their conservation; a 'trap-door' in the net allows the large turtles to escape [6]. Their use is still not widespread however, and even in countries where the use of TED's is mandatory, this is not enforced [7]. A number of major nesting beaches are protected and conservation projects work to artificially rear turtle eggs and then release them. Recently the number of olive ridleys nesting in Mexico has increased [8], and arribadas have returned to the Gahirmatha rookery in Orissa, India. [9]

Sources and Credits 5

1. WWF, some rights reserved, https://www.wwfindia.org/about_wwf/priority_species/lesser_known_species/olive_ridley_turtle/
2. "Recovery Plan for U.S. Pacific Populations of the Olive Ridley Turtle (Lepidochelys olivacea)" (PDF). Silver Spring, MD: National Marine Fisheries Service. 1998. Retrieved 16 April 2013.
3. Ernst, Carl H.; Barbour, Roger W.; Lovich, Jeffrey E. (1994). Turtles of the United States and Canada. Washington [u.a.]: Smithsonian Inst. Press. ISBN 1560983469.
4. Ripple, J. (1996) Sea Turtles. Voyager Press, Stillwater, USA.
5. Shanker, K. (2002) Pers. comm.
6. WWF Turtle Projects (September, 2002)
http://www.panda.org/resources/publications/species/threatened/downloads/Olive_Ridley.doc
7. Shanker, K. (1999) Birth and Death. Sanctuary Asia, 1999: 10 - 14.
8. U.S. National Marine Fisheries Service Recovery Plans (September, 2002)
http://www.nmfs.noaa.gov/prot_res/readingrm/Recoverplans/Olive_Ridley_Recovery_Plan.pdf

Sources and Credits

  1. (c) Brad Flickinger, some rights reserved (CC BY), https://www.flickr.com/photos/56155476@N08/8213122963/
  2. (c) Elí García-Padilla, some rights reserved (CC BY-NC), https://www.flickr.com/photos/elicoatl/7544171502/
  3. (c) Wikipedia, some rights reserved (CC BY-SA), https://www.inaturalist.org/guide_taxa/705957
  4. (c) Wildscreen, some rights reserved (CC BY-NC-SA), https://www.inaturalist.org/guide_taxa/705957
  5. (c) Caleb Cam, some rights reserved (CC BY-SA), https://www.inaturalist.org/guide_taxa/705957

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