Sea Turtle Nesting Season Has Arrived

By Michele “Mimi” Olry

Notice the serrated edges of shell and the shape of the head of the hawksbill turtle. Photo by Brenna Bonene

There are only seven species of sea turtles in the world. Five of them are found in Hawaii — the green sea turtle (native), the hawksbill (native), the leatherback (native), the loggerhead and the olive ridley.

Sea turtle emergencies on Kauaʻi are handled by Mimi Olry of the Hawai‘i Department of Land and Natural Resources. She also serves as the Kauaʻi Marine Mammal
Response Field Coordinator for DLNR’s Protected Species Program, which means she responds to Hawaiian monk seals and cetacean incidents, collects data, assists in research, and provides conservation outreach and education to develop conservation support for protected marine species.

Two of Hawaiʻi’s more common sea turtle species — the threatened green sea turtle (honu) and the more rare, the endangered hawksbill (honuʻea or ‘ea) — start nesting in May. The honu nests from May to September, and the honuʻea nests May to December. Both are protected under state and federal laws, including being listed under the Endangered Species Act of 1973.

Notice the smooth edges of the shell and the shape of head of the green sea turtle. Photo by Bo Blinski

The green sea turtles are no longer harvested for their meat and shell. They have recovered from 67 nesting female turtles to 800 nesting annually, with the majority swimming 800 miles to the remote French Frigate Shoals in the Northwestern Hawaiian Islands.

In contrast, the hawksbill turtle, once hunted for is beautiful shell for tortoise shell jewelry, has not increased in numbers, with only 20-25 females nesting each year, primarily on the Kaʻu coast of the Big Island, South Maui and East Molokai.

Nesting

Green sea turtles nest every two to three years. A female (age 25-35 years) will lay eggs on average four times, about every two weeks at night. While the majority (96 percent) of the nesting occurs in the Northwestern Hawaiian Islands, some nesting occurs on the Main Hawaiian Islands. Last year, nesting activity was observed more frequently on the Main Hawaiian Islands. This is likely a reflection of less people on the beaches during the pandemic shutdowns, so females could haul out undisturbed, and nest pits and tracks were more visible. Researchers are also investigating the impact of Hurricane Walaka that resulted in the destruction and loss of sand and reef to a major sea turtle nesting site on East Island in 2018.

On Kauaʻi, nest pits were found around the island. They were monitored for hatching by biologists with the DLNR and the National Oceanic and Atmospheric Administration.

Females typically dig a four-foot wide and deep pit with their hind flippers and then pile on a mound of sand over the egg chamber. Surprisingly, often when a female turtle comes on the beach at night to nest, she often digs two to three false pits in the sand near beach vegetation alongside the actual nest concealing 100 -120 leathery eggs, making it difficult to detect the location of the eggs. The eggs will hatch in about 60 days. Hatchlings emerge at night to run a gamut of deadly dangers of vegetation entrapment, crabs, birds and sea predators. Few survive to adulthood, with estimates ranging from one in 1,000 to one in 10,000.

Females are disturbed by human activity on the beach. Street and building lights can interfere with nesting and distract hatchlings that normally are attracted to natural light reflected off the ocean. Artificial light sources on the beach waylay hatchlings where they can be run over by vehicles on the beach or trapped inland. Off road vehicles can crush nests, and tire tracks trap the hatchlings. Climate change is causing many threats as well, with increasing temperatures altering sex ratios (higher temperatures select for females) and sea level rise drowning nests or king tides eroding away beaches.

Basking

Green sea turtle basking in a sand beach. Photo by Mimi Olry

Turtles come up on the beach not only to nest, but to bask, and also rest if they are injured or sick. Green sea turtle populations are distributed through warm temperate waters worldwide, but in Hawaiʻi, Galapagos and Australia, they bask to thermoregulate and rest without expending energy to breathe at the surface of the ocean or avoid their natural predators, tiger sharks. Now that turtle populations are recovering, they may come onto shore more frequently in large numbers or individually, day or night. Often turtles throw sand onto themselves, or stay wet near the wave wash to adjust their core temperatures, as reptiles do in the sun.

People can help by giving sea turtles at least 10 feet of distancing while viewing them on land or swimming when they are around. Turtles should not be pursued or touched, as this will disrupt their normal behavior and, as with all wild animals, cause a cumulative level of stress. People should only use camera flash covered by a red filter.

They Have Been Around since Dinosaurs Roamed the Earth

Sea turtles are long-lived, roughly 80-100 years. These gentle reptiles have been around since dinosaurs roamed the Earth, about a 100 million years. They are all now endangered and face many human-related threats, including entanglement in fishing gear, ocean plastic, coastal habitat destruction, poaching of adults and eggs, and climate change.

Threats

A potentially lethal entanglement in fishing line. Photo by Mimi Olry

The greatest threats to sea turtles in Hawaiʻi include:

• Boat strikes by the bow or propeller to turtles resting or breathing at the surface of the ocean cause deadly fractures to the shell carapace.

You can help: When boating in shallow, near shore and in harbor waters, go less than 10 knots and post a person to watch out for turtles.

• Marine debris, pollution, plastic and derelict fishing gear cause entanglements. Monofilament line often entangle and drown turtles. Tourniquet wraps around the flippers or neck slowly amputate and kill turtles.

You can help: Prevent things from entering the ocean. Participate in reef clean ups.

• When fishing, accidental turtle interactions can occur.

Fatal damage to the shell from a propeller strike. Photo by Mimi Olry

You can help: Call NOAA Marine Wildlife Emergency Response Hotline to report the interaction (1-888-265-9840). Fishermen are encouraged to help the turtle directly by reeling in the turtle; hold it by the shell and cut the fishing line close to the hook: release with no line attached.

• The disease fibropapillomatosis can cause debilitating tumors to the eyelids and mouth due to a herpes virus and degraded habitat.

You can help: Report injured or dead turtles, nesting activities or baby hatchlings to the NOAA Marine Wildlife Emergency Response Hotline at 1-888-265-9840.

To report illegal or suspicious activity that may result in turtle injury or death, contact DLNR Division of Conservation and Resources Enforcement during working hours at 808-643-DLNR(3567) or NOAA Marine Wildlife Emergency Response Hotline anytime at 1-888-265-9840.

To report rare hawksbill sightings to www.HIhawksbills.org or RespectWildlife@noaa.gov. To identify a hawksbill from a honu, honu have rounded heads and shell carapace with smooth edges whereas hawksbill turtles have narrow head and pointed beak with serrated edges to the shell.