Green sea turtles are migratory marine reptiles known for their extensive journeys between feeding grounds and nesting beaches. Understanding their reproductive patterns and the specific locations they choose for laying eggs is important for conservation efforts. Their nesting habits are a key aspect of their life cycle, highlighting the need for protection of these sites to support the species’ survival.
Global Nesting Regions
Green sea turtles establish nesting sites across tropical and subtropical oceans worldwide, often returning to the same beaches where they hatched. In the Atlantic, significant nesting occurs in the Caribbean, with Tortuguero in Costa Rica being a prominent site, hosting over 100,000 nests annually and representing the largest green turtle nesting colony in the Western Hemisphere. Ascension Island in the South Atlantic is another major location, with thousands of females migrating from Brazil to nest there each year. Florida’s east coast also serves as the largest nesting site within the United States.
Across the Pacific, important nesting grounds include the Hawaiian Islands, particularly the French Frigate Shoals where over 95% of the Hawaiian green sea turtle population nests, and Australia’s Great Barrier Reef. Raine Island on the northern edge of the Great Barrier Reef is considered the planet’s largest remaining nesting site for endangered green turtles, with tens of thousands of females congregating there seasonally. In the Indian Ocean, green sea turtles nest in countries such as India, Sri Lanka, the Seychelles, Maldives, and Oman, with nesting occurring year-round in various locations.
Characteristics of Nesting Beaches
Green sea turtles select beaches with specific physical attributes for laying their eggs. These beaches typically feature fine, deep sand, which allows for proper nest construction and incubation. The texture and depth of the sand are important for the female turtle to excavate an egg chamber and for the eggs to remain undisturbed during development.
The slope of the beach also plays a role, as turtles need to navigate from the ocean to above the high tide line to prevent nests from being inundated by waves. Beaches with some vegetation can offer stability to the sand and provide a degree of camouflage for nesting females and their nests.
The Nesting Ritual
Upon arriving at a chosen nesting beach, typically at night, a female green sea turtle begins a sequential process to lay her eggs. She first crawls ashore, often above the high tide line, and uses her front flippers to dig a “body pit” to settle into. Following this, she employs her hind flippers to excavate a deeper, bottle-shaped egg chamber, which can extend up to a meter deep.
Once the egg chamber is ready, the female deposits her clutch of eggs, which are soft-shelled and resemble ping-pong balls, into the cavity. A single clutch can contain an average of 110 eggs, ranging from 75 to 200. After laying, she covers the eggs with sand using her hind flippers and then camouflages the entire nest site by scattering more sand with her front flippers before returning to the ocean.
Protecting Nesting Grounds
Green sea turtle nesting grounds face threats that impact their populations globally. Coastal development and rising sea levels contribute to habitat loss and degradation, as sandy shores are submerged and eroded. Light pollution from nearby human settlements disorients both nesting females, deterring them from coming ashore, and hatchlings, leading them away from the ocean towards artificial light sources. Poaching of adult turtles and their eggs also continues in some regions, despite protective measures.
Climate change presents additional challenges, with increasing sand temperatures altering the sex ratio of hatchlings, often resulting in a disproportionate number of females. More frequent and intense storms, also linked to climate change, can wash away nests and erode beaches. Conservation efforts, including establishing protected areas, implementing monitoring programs, and engaging local communities, are important for safeguarding these nesting locations and supporting the recovery of green sea turtle populations.