Olive Ridley turtles are the smallest marine turtle species in the world. They were named after H N Ridley who first reported their sighting in 1887 in Brazil and for their olive green colour. Adults grow up to 70 cm long and weigh around 45 kg. They are found worldwide in the tropical and warm waters of the Pacific and Indian Ocean. These turtles, which are also found in the Atlantic Ocean, are believed to use the coastal waters of over 80 countries. They cover thousands of kilometres between their foraging and nesting grounds. Even though historically Olive Ridley turtles were considered the most abundant sea turtle in the world their population has plummeted over the past few decades.
Nesting Practices
Olive Ridley Turtles are best known for their behaviour of synchronised nesting in mass numbers, termed ‘arribada’, which means mass arrival in Spanish. They nest in the narrow beaches near estuaries and bays. Each female turtle lays approximately 100-140 eggs at a time during the nesting season which is usually between November and March.
In India, the ‘arribada’ takes place in Odisha at three nesting grounds — Gahirimatha, Devi River mouth and Rushikulya River mouth. To a lesser extent the turtles nest on beaches in Andhra Pradesh and Tamil Nadu as well.
Threats They Face
The Indian Ministry of Environment and Forests allowed two major companies of India — Oil and Natural Gas Corporation Limited (ONGC) and Reliance Industries Limited — to carry out off-shore drilling off the coast of Orissa. They were allowed to drill 20 exploratory wells in the area. One of the blocks that ONGC was allotted is located around the Chilika lake which is the largest brackish water lagoon in Asia.
Any instance of oil spills will cause serious damage to the fragile lake habitat, which is home to the rare Irrawaddy Dolphin and the migratory waterfowl.
The new port at Dhamra, which is a joint venture between Tata Steel and Larsen and Toubro, lies at a distance of less than 15 km from the Gahirmata Marine Sanctuary. This is a matter of great concern as pollution and artificial lighting from the port are a major threat to the survival of the nesting turtles. The livelihood of thousands of fishermen in the area has been thrown into jeopardy because of the port.
Turtles have suffered severely because of mechanised fishing and trawling as well. News reports about Olive Ridley turtles getting washed ashore on the beaches of Odisha are commonplace now.
Olive Ridley turtle eggs can be legally collected in Costa Rica which is viewed as biologically sustainable and economically viable. However, in most regions, illegal poaching of eggs is considered a major threat, and thus the practice of allowing legal egg harvests continues to attract criticism from conservationists.
Need to Conserve Them;
Recent studies suggest that Olive Ridley turtles that nest on India’s east coast are genetically distinct from other populations and could be the ancestors of populations in other oceans.
Banning fishing activities along the coast without ensuring the fishermen an alternate livelihood will not meet the objective of conserving the turtles. Key areas should be identified with the help and knowledge of local communities and promoted as marine reserves. They should be protected from short-sighted development. Authorities should take steps to tackle the problem of industrial pollution and illegal aquaculture farms along the coast that are playing havoc with the environment.
Turtles are a very vulnerable species as only one in every 1,000 hatchlings survives to adulthood. Raising awareness on the beauty and value of the marine environment in Odisha is the first step to ensure the environment is left intact so that the turtles can continue to congregate in these waters. Each year that passes without improvement in their mortality rates will lead to the loss of breeding turtles and a dangerous decline in their population.