Indian Ocean Subpopulation of Leatherbacks Threatened by Human Actions

The leatherbacks in the Indian Ocean are threatened by an infrastructure project on Great Nicobar Island

Leatherback turtles are the biggest sea turtles in the world. They can grow up to 2 m long and weigh up to 700 kg or more. As other sea turtle species, they are already threatened by extinction even though they have a very widespread distribution all around the world. They live in areas as far north as Alaska and Norway and as far south as New Zealand. 

Life Cycle

After mating in high seas, female turtles usually come back to the same nesting beach to lay their eggs. About two months afterwards, the turtles hatch and make their way to the ocean, where they will live for the next years, looking for food and hiding from predators. Of those there are many; already on the beach there is danger of being eaten by crabs, birds, mammals or reptiles. Then, in the ocean, they are predated by larger fish and sharks, so the chances of survival are quite low for leatherback hatchlings. 
Leatherbacks reach maturity only after 15-25 years. Once they are ready to lay their eggs, they return to the beach where they were born. 

Indian Ocean Subpopulation

It is known that there is a small subpopulation of leatherbacks in the Indian Ocean. However, there is very little research being done there. The Great Nicobar Island that lies between mainland India and Thailand plays a very important role for not just leatherbacks but also other animal and plant species. The island is still very intact and untouched by humans, and large parts of it is a biosphere reserve. It is home to many different and rare species, among others the leatherback turtles, which come to nest on this island. It is not only a peaceful habitat for animals, but it is also home to indigenous people. 

Precisely on this island, there are now plans to build a huge infrastructure project, including a port, a trans-shipment port, an international airport, a power plant and a new township. All of this is supposed to be built, not only but also, on 130 square kilometers of primary forest. This would mean cutting nearly one million trees in the rainforest ecosystem. 

The project does not only cut down trees of the rainforest, it also impedes leatherbacks from reaching their nesting beaches. This is done even though the subpopulation there is already critically endangered. Experts are concerned about the environmental damage the project will cause. The construction would significantly alter the coast and other habitats, including coral reefs, mangroves and coastal forests. Like in this case, loss of nesting site contributes greatly to the extinction of sea turtles. Once again, it is human action and economy against nature and wildlife. 

Why Sea Turtles are in Danger of Becoming Extinct

As always when it comes to influencing wildlife and the environment, humans play a decisive role. This is also true for the turtle populations. Turtles and turtle eggs around the world are stolen and consumed. Local communities consider it a delicacy, some even an aphrodisiac. Leatherbacks are not as commonly eaten as other sea turtles because their flesh contains a lot of oil and fat. Moreover, turtle shells are used to make jewellery and other artefacts. 

Another reason for becoming endangered – and again caused by humans – is pollution of oceans. Turtlebacks and the other sea turtles feed mainly on jellyfish, which look frighteningly similar to plastic bags and other plastic waste found in the ocean. According to research, approx. one third of adult leatherbacks ingested plastic. This obstructs their digestive tracts and already a small quantity of marine debris can kill them. 

Light pollution is another great problem faced by sea turtles. They follow bright light, so if there are buildings along the beach with lights on at night, they go towards the buildings, instead of back to the ocean. This is also problematic for the hatching of baby turtles because they do not know which way to go in order to reach the ocean. 

Especially young turtles and the eggs are preyed upon, not just by humans but also by other coastal predators, e. g. crabs, lizards and shorebirds. Once in the ocean, sharks and various other large fish prey on baby turtles. For them, the chances of survival are very low, so we should do everything we can to protect them, including protecting habitats.