The Olive Ridley Sea Turtle Paradox

Image of Mature Olive Ridley Sea TurtlePhoto: Bernard Gagnon

Every year, Olive Ridley Sea Turtles gather at relatively few beaches to dig nests and lay eggs. These small ocean-going turtles are at risk for several reasons.

Nesting on Tropical Beaches
An “arribada” is a mass nesting event. Thousands of female turtles meet in shallow offshore waters. Triggered by signals unknown to scientists, the majority will go ashore simultaneously. Each digs her nest and lays about one hundred eggs, then returns to the sea.

A single turtle might lay one to three clutches of eggs on a monthly basis. A few females are solitary nesters and lay their clutches about twice as frequently.

The eggs incubate for almost two months. The hatchlings race to the sea, hoping to live long enough to mate. In fifteen years, the surviving females will again return to lay their own eggs.

The Olive Ridley Sea Turtle lives in the tropics of the Atlantic, Indian and Pacific Ocean. Mexico, Nicaragua and Costa Rica are the hosts in the Americas. Sri Lanka and eastern India have the other main nesting sites.

Baby Olive Ridley Sea Turtle on beachPhoto: Caulier Gilles

Vital Statistics of the Olive Ridley Turtle

Small for a sea turtle, the Olive Ridley grows to about 30 inches (80cm) in length and weighs up to about 100 pounds (45kg). Their diet includes crabs and other crustaceans, jellyfish and algae. The upper shell is an olive colour. Each flipper has one or two claws.

Olive Ridley Sea Turtle laying eggsPhoto: Liz Roy

A Numerous but Threatened Species in India

The number of nesting females has been estimated at about 800,000. Yet these numbers show a serious decline; so has the average size of the turtles joining in the arribadas. Taken together, these observations raise alarms among marine biologists.

These turtles, and their eggs, have been harvested for food; they are plentiful and easily obtained during the arribada. Where environmental protection has been implemented, however, some nesting sites have shown signs of recovery.

Yet, the greater problem may be demonstrated in concerns in India. Trawlers continue to catch fish, and entangle turtles in their nets. Some conservationists in India had persuaded the government and the Supreme Court to take specific actions to protect this species. Despite claims that trawlers avoid using the “Turtle Excluder Device” on their fishing nets, some officials insist that compliance is high.

As well, coastal dredging operations to ensure safe navigation may cause incidental damage to the beaches favoured by the Olive Ridley Sea Turtle.

Baby Olive Ridley TurtlePhoto: The High Fin Sperm Whale

An Endangered Species on Mexico’s Pacific Coast

The breeding population had declined very seriously on Mexico’s western coast, leading to an “endangered species” status. The population has stabilized since 1990, due both to a ban on harvesting them, plus the requirement for the “Turtle Excluder Device” on trawlers’ nets.

Mexico provides a hopeful example for the rest of the world to follow. Enforcement of the correct conservation protocols can save the world’s Olive Ridley Sea Turtle population.

Olive Ridley Sea Turtles off into the sunsetPhoto: The High Fin Sperm Whale

References:

US Fish and Wildlife Service, “Olive Ridley Sea Turtle“, modified Jan. 16, 2009, referenced Nov. 17, 2010.

NOAA Fisheries, “Olive Ridley Turtle“, referenced Nov. 17, 2010.

Sandeep Mishra, “Conservationists worried over safety as endangered Olive Ridleys arrive“, published Nov. 9, 2010, referenced Nov. 17, 2010.

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