Olive Ridley Turtle

The infamous olive ridley arribada

“the dancing queen of turtles”

Taxonomy

Kingdom:   Animalia
Phylum:      Chordata
Class:           Reptilia
Order:        Testudines
Family:       Cheloniidae
Genus:         Lepidochelys
Species:       Olivacea
Status:         Vulnerable
Malaysian name – Penyu Lipas

Olive ridley’s measure only 60-65cm in shell length and are the smallest known sea turtle species.  Olive ridleys are also the most abundant species globally nesting from the west coast of the America’s to Australia, the pacific islands and into the Indian Ocean.  Olive ridleys were thought to be prevented from going into the Atlantic ocean by the cold waters around the cape of good hope in Africa.  This created one of their common names which is the Pacific Ridley, however in recent years Olive Ridleys have been found nesting on beaches bordering the Atlantic Ocean.  The close cousin of the Olive Ridley is the Kemp’s Ridley which is mainly found in Caribbean waters but is thought to be restricted to the Atlantic Ocean.  The species were thought to have formed when the America land masses collided creating the Atlantic and Pacific ocean basins.

The olive ridley is nicknamed the dancer of the sea turtles due to their strange nesting habits.  They are the smallest thus the lightest of the sea turtles and crawl up the beach using all four flippers.  They do not dig body pits and covers over their eggs by bouncing up and down with their shell to compact the sand which looks like dancing.

Another fascinating fact about Olive Ridley’s is their synchronised breeding aggregations when up to 30,000 turtles can laid their eggs in a four day period on beaches in Costa Rica and India – called Arribada.  The onslaught of nesting turtles, their small size and olive colour is what led to their Malaysian name which translated into English means cockroach turtle.

Anatomy and morphology

These lightly-built turtles have an average weight just over 46 kilograms (100lb). They have a high-domed shell, with a carapace length of only 76centimetres (30in). 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

Olive Ridley turtles are usually found in the Indo-Pacific oceans. The common name in Spanish is tortuga golfina, del golfo o lora.

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 that 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 Costa Rica is the one of the most important nesting sites of this turtle. Ostional Beach in Guanacaste Province has the highest concentration of these turtles monthly, where the “arribadas” – mass arrival and nesting of turtles – occur every month. In October and November Olive Ridley turtles nest in the highest quantity in this place (approximately 200 turtles per hour). Nancite Beach and Camaronal Beach in the same province of this Central American country receive a lot of Olive Ridley turtles, but less than Ostional.

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.

Lepidochelys olivacea distribution map. Red circles are major nesting grounds. But the construction of Dhamra Port by TATA Group is supposed to be a major threat to these turtles.Yellow circles are minor nesting beaches.

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.

In Peninsular Malaysia, nestings of Olive Ridley’s is very sparse with no significant areas of nesting.  Nestings have been recorded in the last 10 years in Pulau Penang, Redang and beaches of Kelantan, Perak, Pahang and Terengganu.