Olive Ridley turtles and their conservation

Why in news?

The Rushikulya rookery coast in Ganjam district of Odisha is a major mass nesting site for Olive ridley turtles in India.

This year (2017), over 3,85,000 mother turtles reached the coast to lay eggs. Each nest contains around 100 eggs. This means over three crore hatchlings are expected to come out of the nests. On an average, 80 hatchlings come out of each nest.

Olive ridley turtles: Taxonomic and threat status

Kingdom:  Animalia

Phylum: Chordata

Class: Reptilia

Scientific Name: Lepidochelys olivacea

IUCN Red List Category: Vulnerable

It is also listed in Appendix I of CITES. This listing is largely responsible for halting the large scale commercial exploitation and trade of Olive Ridley skins.

About the species

They are the smallest of the sea turtles and currently the most abundant.

Their vulnerable status comes from the fact that they nest in a very small number of places, and therefore any disturbance to even one nest beach could have huge repercussions on the entire population.

The name for this sea turtle is tied to the color of its shell—an olive green hue.

Why they matter

Sea turtles are a fundamental link in marine ecosystems and help maintain the health of coral reefs and sea grass beds.

Olive ridley turtles also provide a type of refuge for many seabirds in the Eastern Pacific, allowing them to perch on their shells as the turtles surface to bask in the sun.

Habitats in India

These turtles spend their entire lives in the ocean, and migrate thousands of kilometers between feeding and mating grounds in the course of a year.

Interestingly, females return to the very same beach from where they first hatched, to lay their eggs. During this phenomenal nesting, up to 600,000 and more females emerge from the waters, over a period of five to seven days, to lay eggs. They lay their eggs in conical nests about one and a half feet deep which they laboriously dig with their hind flippers.

The coast of Odisha in India is the largest mass nesting site for the Olive-ridley, followed by the coasts of Mexico and Costa Rica.

In India, the major mass nesting site for them is at:

  1. Rushikulaya rookery coast in Ganjam district in Odisha.
  2. Gahirmatha beach in Odisha.

They also breed along Tamil Nadu coast and Krishna Wildlife Sanctuary, a wildlife sanctuary and estuary located in Andhra Pradesh.

Threats

Olive-Ridleys face serious threats across their migratory route, habitat and nesting beaches, due to human activities such as,

  • Turtle unfriendly fishing practices,
  • Development and exploitation of nesting beaches for ports, and tourist centres.
  • Though international trade in these turtles and their products is banned under CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) Appendix I, they are still extensively poached for their meat, shell and leather, and their eggs, though illegal to harvest, have a significantly large market around the coastal regions.
  • Climate change: All stages of a sea turtle’s life are affected by environmental conditions such as temperature—even the sex of offspring. The warmer the nest beach conditions, the more female hatchlings that emerge from the eggs. Unusually warm temperatures caused by climate change could be disrupting normal sex ratios, resulting in fewer male baby turtles. Warmer sea surface temperatures can also lead to the loss of important foraging grounds for marine turtles, while increasingly severe storms and sea level rise can destroy critical nesting beaches and damage nests.
  • The illegal harvest of olive ridley eggs in the Central American region continues, and there is also high mortality of adults due to coastal fisheries that do not yet use Turtle Excluder Devices (TEDs) in their nets

To reduce accidental killing in India, the Odisha government has made it mandatory for trawls to use Turtle Excluder Devices (TEDs), a net specially designed with an exit cover which allows the turtles to escape while retaining the catch. However, this has been strongly opposed by the fishing communities as they believe TEDs result in loss of considerable amount of the catch along with the turtle.

Forest department of Odisha has also imposed restrictions on entry of visitors and tourists to over three kilometre stretch of beach during nesting season.