Lepidochelys olivacea

Scientific Name:-

Lepidochelys olivacea

Common Name:-

Olive Ridley / Pacific Ridley

Malayalam Name:-

Olive Ridley Kadalama

Category:-

Sea turtles

Status:-

Vulnerable A2bd ver 3.1 (IUCN Redlist); Appendix I of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora); and listed in Convention on Migratory Species (CMS).

Description:-

The name of the olive ridley originates from the olive colour of the adult’s carapace. Its head is small and triangular with two pairs of prefrontal scales. The smooth carapace has 6 or more lateral scutes (scales) and is nearly circular. Adults are dark grey green, while hatchlings are black when wet with greenish sides. Olive ridley is the smallest of all the sea turtle species (length of the carapaces is approximately 65 cm and reaches up to 50 kg.). Both the front and rear flippers have one, or sometimes two visible claws. Rarely an extra claw is present on the front flippers. Track marks are about 70 -80 cm wide, are light and have asymmetrical, oblique marks that are made by forelimbs. The tail drag mark is usually absent or usually remain inconspicuous. Their large and powerful jaws are adapted to their diet of mostly on shrimp and crabs, molluscs, tunicates and fish. individual Olive Ridleys may nest one or two times per season, with approximately 100–110 eggs per clutch, which require 52 to 58 days incubation period. Nesting takes place individually or in groups (arribadas). The nesting in Kerala occurs individually in beaches, especially in Northern Kerala (November-January months). In contrast to other sea turtle species, the reproductive cycle is nearly annual (over 60% of turtles nest every year.

Threats:-

Poaching for meat and eggs; habitat destruction, particularly sand mining in estuaries (in Kerala), coastal development projects; incidental capture in commercial fisheries are main concerns for the survival of this species.

Remark:-

Olive ridleys are known for their arribadas or synchronised mass nesting during which time tens of thousands of female ridleys come ashore to nest in the span of a few days. As a result, millions of hatchlings will finally emerge from the nest during night and return to the sea. The largest arribadas in the world exists in Gahirmata (Orissa) in India. They often come back to the same place for nesting after a long stay towards maturity at the sea.

Habitat:-

Olive ridleys are found throughout the tropical waters of the Pacific, Indian and southern Atlantic Ocean. In India they are generally found in coastal waters (rarely entering estuaries), but can be very oceanic over some parts of its range. They typically forage off shore in surface waters or dive to depths of 150 m to feed on bottom dwelling crustaceans. Like most other sea turtles, Olive Ridleys display a complex life cycle, which requires a range of geographically separated localities and multiple habitats. Females lay their nests on coastal sandy beaches from which hatchlings emerge and enter the marine environment to continue their development. They remain in a pelagic phase, drifting passively with major currents that disperse far from their natal sites, with juveniles sharing some of the adults’ habitats until sexual maturity is reached. Reproductively active males and females migrate toward coastal zones and concentrate near nesting beaches. Their post-breeding migrations are complex, with pathways varying annually.

Synonyms:-

Testudo mydas Linnaeus, 1758; Chelonia olivacea Eschscholtz, 1829

References:-

Abreu-Grobois, A & Plotkin, P. (IUCN SSC Marine Turtle Specialist Group) 2008.Lepidochelys olivacea. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. <www.iucnredlist.org> Downloaded on 01 August 2013.
Bhaskar, S. 1981. Sea turtle survey of the Kerala coast. Report to the WWF-India, 6pp.
Bhupathy, S. 2007. Monitoring of marine turtles along the Kerala and Tamil Nadu coasts. Indian Ocean Turtle Newsletter 5: 1–9.
Das, I. 1995. Turtles and tortoises of India. Oxford University Press, Delhi.
Deepak Apte (2012). Field Guide to the Marine Life of India. Deepak Apte, Thane, Maharashtra, 502pp.
Dileepkumar, N. and Jayakumar, C. 2002. Field study and networking for turtle conservation in Kerala – A GOI-UNDP sea turtle project report.
Dileepkumar, N. & C. Jayakumar. 2006. Sea turtles of Kerala. In: In: Marine turtles of the Indian subcontinent (K. Shanker, B.C. Choudhury, Eds). Pp. 137–140. Universities Press (India) Private Ltd.
Palot, M.J. and Radhakrishnan, C. 2004. Status and distribution of turtle fauna (Testudines: Reptilia) in the Malabar part of Kerala, India. Records of Zoological Survey of India, 102(Part 1-2): 27–39.
Sea turtles of India. 2011. A comprehensive field guide to research, monitoring and conservation (Compilers. S. Shenoy, T. Berlie and K. Shanker). Dakshin Foundation, Bangalore and Madras Crocodile Bank Trust, Mamallapuram, India. 148pp.

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