Regarded as one of the smallest sea turtles in the world, the Olive Ridley Turtle is found in the warm and tropical waters, primarily in the Pacific and the Indian Ocean. They get their name from olive- coloured carapace, which is heart shaped and well rounded. Olive Ridley Turtles are the most widespread of marine turtle
with their range expanding across the coastal waters of over 80 countri
They show sexual dimorphism i.e. the male and female of this species can be identified separately by their external morphology. The male is larger, has a more prominent, longer and thicker tail which aids during mating. Males also have enlarged and hooked claws on the it’s front flippers which allows him to grasp the female during mating.
Like most sea turtles, these too come to land only for laying eggs. Mother digs up a cavity in sand with the help of their hind flippers and lays its eggs there and then covers them up again to secure the eggs from the predator and help in incubation.
Olive ridley turtles exhibit two different nesting behaviours, the most prevalent solitary nesting, but also the behaviour they are best known for, the synchronised mass nesting, termed ‘ arribadas.’ The coast of Orissa is one of the largest ‘arribadas’ nesting sites of Olive Ridley whereas solitary nesting occurs in Coromandel coast and Sri Lanka.
After around 45–65 days, the eggs begin to hatch and dark grey coloured hatchlings can be seen in swarms crawling in the beach, making their first trek towards the vast ocean.
Even though they are abundant in range, globally they have declined by more than 30% from their historic range. Now, they have been given the ‘Vulnerable’ status by the IUCN
.
- Olive Ridley’s eggs are easily predated by snakes, crocodiles and crabs.
- Hatchlings on their way to the ocean are preyed upon by seabirds, crabs, crows, Brahminy Kites, jackals and wild boars.
- Eggs are also susceptible to drowning due to high tides.
- Digging up of nests by these predators also disrupts the incubation of remaining eggs which may result in their destruction.
- The greatest single cause of egg loss, results from arribadas, in which the density of nesting females is so high, previously laid nests are inadvertently dug up and destroyed by other nesting females.
- Nests may get contaminated by bacteria and pathogens, resulting in rotting of eggs.
- Big fishes also feast on these hatchlings as soon as they reach the ocean.
- Adults have been observed to be predated by Sharks and Killer Whales.
- Introduction of alien species like pigs and feral dogs
in the nesting sites by humans results in predation of the eggs and hatchlings by these alien species in huge numbers, hence damaging the population.
- Humans directly are still listed as the leading threat to Olive Ridley since they are responsible for unsustainable egg collection, slaughtering nesting females on the beach and directly harvesting adults at sea for commercial sale of both meat and hides.
- Mortality associated with boat collisions,
- Incidental takes in fisheries
- Trawling, gill nets, ghost nests, longline fishing, and pot fishing have significantly affected their populations.
- Entanglement and ingestion of marine debris.
- Coastal development, climate change
, and other sources of beach erosion have also been cited as potential threats to nesting grounds.
- Coastal development also threatens newly hatched turtles through the effects of light pollution. Hatchlings which use light cues to orient themselves to the sea are now misled into moving towards land, and die from dehydration or exhaustion, or are killed on roads.
- They have been listed in Appendix I of CITES
, which is responsible for halting the large- scale commercial exploitation and trade.
- Many NGOs in India and outside India work together to ensure that no egg collection and poaching takes place in nesting sites.
- Enforcing the use of turtle excluder devices in the shrimp-trawling industry has also proved effective in some areas.
- Many schools arrange trips for students to carry out the conservation project, especially in India.
- Many projects worldwide are working on preserving the Olive Ridley’s eggs. These eggs are relocated in hatcheries, where they are protected from various threats including predation. When the baby turtles come out, they are picked up and directly released into the ocean.
- In Chennai, India, one such project by the Chennai wildlife team involved collection of close to 10,000 eggs along the Marina coast, of which 8,834 hatchlings were successfully released into the sea in a phased manner.
We at Think Wildlife Foundation
recently launched our Livelihoods for Conservation project to provide alternative, sustainable livelihoods to the communities living with wildlife. This is with the aim to incentivize conservation
while uplifting these communities economically. You can purchase merchandise from these communities here
!
Originally published at https://thinkwildlifefoundation.com
on July 8, 2023.
