Sea turtles are a significant part of Hawaii’s marine environment, with their nesting and hatching cycles being a natural spectacle. These ancient mariners undertake incredible journeys to perpetuate their species, returning to sandy shores to lay their eggs. The emergence of tiny hatchlings is a key event.
Hatching Season in Hawaii
Sea turtle hatching in Hawaii typically occurs from July through December. Green sea turtles, known locally as honu, are the most frequently encountered species. Their nesting season spans from late April through October, with hatchlings emerging approximately two months later, peaking between August and November. While many Hawaiian green sea turtles nest in the remote French Frigate Shoals, part of the Northwestern Hawaiian Islands, some nesting also occurs on the Main Hawaiian Islands, including beaches on Oahu, the Big Island (Punaluʻu and Kiholo Bay), and Molokai.
Hawksbill sea turtles, or honu ʻea, are less common but also nest in Hawaii. Their nesting season runs from May to December, with hatchlings emerging around July to February. Honu ʻea primarily nest along the remote Kaʻū coastline on the southeast side of the island of Hawaii. Smaller numbers of nests are found on isolated beaches on Maui, Molokai, and Kauai. The exact timing of emergence can vary slightly depending on environmental conditions and when the eggs were laid.
From Nesting to Hatching
After mating, a female sea turtle returns to a sandy beach to create her nest. She uses her rear flippers to dig an egg chamber, typically two feet deep. Inside, she deposits a clutch of over 100 eggs, then carefully covers them with sand. A single female can lay multiple clutches within a nesting season, usually every two weeks over several months.
The eggs incubate in the warm sand for about 60 days, though this period fluctuates with sand temperature. Environmental temperature plays a significant role in determining the sex of developing hatchlings, a phenomenon called temperature-dependent sex determination (TSD). Warmer sand temperatures produce more female hatchlings, while cooler temperatures result in more males. Temperatures between 81.86°F (27.7°C) and 88.8°F (31°C) can yield a mix of sexes.
The Hatchlings’ Journey
After about 60 days of incubation, hatchlings use a temporary egg tooth to break free from their shells. They cooperatively dig to the surface, a process that can take several days. Hatchlings typically emerge at night, avoiding daytime predators and sun. This mass emergence is often called a “turtle boil” because the sand appears to bubble as they surface.
Once on the beach, hatchlings instinctively orient toward the brightest, lowest horizon, usually the ocean, guided by moonlight and starlight. The crawl across the sand helps them imprint on their natal beach, which may guide their return decades later for reproduction. Upon reaching the water, they enter a “swim frenzy,” swimming continuously for 24 to 48 hours to reach deeper, offshore waters, away from nearshore predators.
Protecting Hatchlings and Nests
Protecting sea turtle nests and hatchlings in Hawaii requires mindful public practices. Observe these animals from a respectful distance of at least 10 feet (3 meters); never touch, feed, or chase them. Disturbing nests or hatchlings is illegal under the Endangered Species Act and state laws. If you encounter a nesting turtle or marked nest, stay back and avoid blocking their path to or from the ocean.
Artificial lighting near beaches poses a significant threat to emerging hatchlings. These lights can disorient them, causing them to crawl away from the ocean towards land, increasing risks of predation, dehydration, or being run over. During nesting season, turn off beach-facing lights and use red-filtered flashlights if on the beach at night, as red light is less disruptive. Avoid driving on beaches, which can crush unseen nests or create ruts that trap hatchlings.
Always dispose of trash properly to prevent entanglement or ingestion by marine life. Report distressed animals or suspected nesting activity to authorities like the NOAA Marine Wildlife Hotline to aid conservation.