Kurma mela: The science of the mass nesting of Olive Ridley turtles

Context

In March 2025, a record-breaking arribada (mass nesting event) of over seven lakh Olive Ridley turtles (Lepidochelys olivacea) was observed at Rushikulya beach, Odisha. While this event was celebrated as a sign of ecological recovery, it also raised significant concerns among conservationists regarding the long-term sustainability of such mass nesting and the unintended consequences of human interventions.

About Olive Ridley Turtles:

Scientific Name: Lepidochelys olivacea
Conservation Status: Vulnerable (IUCN Red List)
Global Distribution: They are found in warm tropical and subtropical waters, with primary nesting sites along the Pacific coasts of Mexico and Central America.
Indian Context: Odisha is a critical nesting site, with three major rookeries: Gahirmatha, Devi, and Rushikulya.

Nesting Behavior and Ecology:

Arribada: A unique mass nesting phenomenon where thousands of female turtles come ashore simultaneously to lay eggs.
Philopatry: Turtles return to the beaches where they hatched, guided by the Earth’s geomagnetic field.
Environmental Triggers: Nesting site selection is influenced by factors such as cold-core eddies (nutrient-rich water currents), beach slope, salinity, rainfall, and predation risk.
Sex Determination: Temperature-dependent; higher sand temperatures result in a higher proportion of female hatchlings.

Key Nesting Sites in Odisha:

Gahirmatha Beach: It is located between the Brahmani and Baitarani river mouths.
Devi River Mouth – It is approximately 100 km south of Gahirmatha.
Rushikulya River Mouth – Around 320 km south of Gahirmatha.

PYQ

1. Consider the following statements: (2019)

Some species of turtles are herbivores.
Some species of fish are herbivores.
Some species of marine mammals are herbivores.
Some species of snakes are viviparous.

Which of the statements given above are correct?

1 and 3 only
2, 3 and 4 only
2 and 4 only
1, 2, 3 and 4

2. In India, if a species of tortoise is declared protected under Schedule I of the Wildlife (Protection) Act, 1972, what does it imply? (2021)

It enjoys the same level of protection as the tiger.
It no longer exists in the wild, a few individuals are under captive protection; and now it is impossible to prevent its extinction.
It is endemic to a particular region of India.
Both (b) and (c) stated above are correct in this context.