Sea turtle nesting season underway
Biologists are urging beachgoers to be conscientious as sea turtle nesting season carries on throughout the state, as there may be more turtles nesting on the main Hawaiian Islands than there have been for years.
Nesting season for both green and hawksbill sea turtles lasts roughly from April to October and involves the amphibians crawling up beaches to deposit eggs in the sand. When the eggs hatch, the hatchlings attempt to make their way to the sea, which is where human impact most often disrupts the process.
Sheldon Plentovich, coastal program coordinator for the U.S. Fish and Wildlife Service in the Pacific Islands, said any light sources on the beach — or even visible from the beach — will confuse and disorient any nesting female turtles, but will have disastrous effects on hatchlings, which will attempt to follow the light source away from the water and will, most likely, die of exhaustion, dehydration or predation.
In one example, Plentovich said that a white light visible from miles away led to hundreds of turtle hatchlings dying at James Campbell Wildlife Refuge on Oahu when they attempted to follow the light inland.
“Ideally, you’re not using any lights at all,” Plentovich said. “But if you have to use a light, use one with longer wavelengths in the red, orange or amber spectrums.”
Irene Kelly, sea turtle recovery coordinator for the National Oceanic and Atmospheric Administration, said the critically endangered hawksbill sea turtle’s primary Hawaiian nesting sites are on the Big Island or Molokai. Last year, she said, there were 53 confirmed hawksbill nesting sites on the Big Island, although she added that most of them are in extremely isolated areas — Kamehame Beach in Ka‘u is probably the closest nesting site to human habitation.
“But sometimes fishermen will set up camp around beaches like that, and the lights will still affect the hatchlings,” Kelly said.
Kelly urged anyone who sees a hawksbill turtle — identifiable by the serrated edges on its shell, narrow head, pointed beak and four scales between its eyes — to report the sighting to NOAA.
“There are so few hawksbills that they’re very hard to monitor, so we rely on public reports,” Kelly said, adding that volunteer programs to monitor for hawksbills were suspended during the COVID-19 pandemic.
On the other hand, while green sea turtles rarely nest on the Big Island, Plentovich said that turtle species has been nesting more and more in the state over the last several years. In 2018, there were zero recorded green sea turtle nesting sites on Oahu. In 2021, there were 67.
“Everyone was assuming that it was because of COVID, because there were fewer people on the beach,” Plentovich said. “But there were 10 nests in 2019, so it seems unlikely that it’s just because of people on the beach.”
Plentovich said one theory for the change in nesting behavior is related to the 2018 Hurricane Walaka, which developed south in September of that year and struck the French Frigate Shoals to the northeast of the main Hawaiian Islands.
Unfortunately, Plentovich said, East Island in the shoals was one of the last safe nesting sites for green sea turtles and was mostly washed away by the storm surge. Without East Island, turtles have been returning to more dangerous nesting grounds, which unfortunately includes the main Hawaiian Islands.
“Turtles try to go back to where they were born to nest,” Plentovich said. “If they can’t do that, that’s a big shift in turtle behavior.”
Plentovich added that East Island was, on average, only 1.3 meters above sea level, and that climate change and rising sea levels will likely continue to force turtles to nest in more dangerous areas.
To report a hawksbill sighting, email respectwildlife@noaa.gov or call (888) 256-9840.
Email Michael Brestovansky at mbrestovansky@hawaiitribune-herald.com.
