Humans pushed sea turtles to the endangered-species brink—but we can also bring them back
Worldwide, green sea turtle populations are endangered. Their numbers have dropped by 90 percent from historical levels. In the Hawaiian islands, the Endangered Species Act put our sea turtles (honu) on a path to recovery, and the green sea turtle population that lives here is considered of least concern, rather than endangered or threatened.
While the story of honu in Hawai‘i is one on a trajectory to success based on the numbers, this does not mean that our turtles have it easy. For a turtle to reach adulthood, which takes anywhere from 20-30 years, it must avoid predators, disease, and other natural hazards, just for a start. The odds of a turtle surviving to that age are about 1,000 to one.
Let’s consider some of the challenges sea turtles face on their path to becoming a grown-up.
Green sea turtles in Hawaiʻi are more at risk from climate change. Courtesy flickr/quintanomedia
Nests and hatchlings are vulnerable to a range of dangers. Storms can flood nests or simply wash them away. People driving on beaches can crush nests or harden the sand to the point where the hatchlings can’t dig out. Predators above and below the water consider the flippered little morsels a tasty treat. Pigs, mongooses, rats, dogs, and cats are all known to disrupt sea turtle nests and eat eggs and hatchlings.
While storms have always posed some danger to sea turtles, climate change is increasing the frequency and magnitude of threats. Sea level rise and stronger storms will increase the reach of waves during average and stormy conditions. Some of this erosion will be temporary, but over time some beaches are certain to permanently disappear. This means fewer places for honu to nest and rest.
Hawai‘i’s honu are more at risk from climate change than other populations worldwide. Ninety-six percent of our green sea turtles travel north to nest on the sandy islets of Kānemiloha‘i (French Frigate Shoals) in the Papahānaumokuākea Marine National Monument. These islets have been disappearing in recent years. Whale-Skate Island went from the second-most important nesting site in the 1960s to being fully submerged in 30 years. All 11 acres of East Island, the most important nesting site at the time, were washed away by a hurricane in 2018 and the islet has yet to reform to the point of being a viable nesting site.
While natural hazards and predation make life challenging for all species of sea turtles, humans are ultimately responsible for the endangered state of all of the world’s sea turtles and remain a primary threat. Legal hunting in Hawai‘i stopped being a major contributor to sea turtles’ deaths in 1978 when they were listed under the Endangered Species Act. Protection from hunting and disturbance are the primary drivers for the recovery of this species.
Still, people negatively affect honu through their actions. Hatchlings typically emerge from nests in the dark, and light pollution from coastal buildings and street lights can disorient the hatchlings and pull them away from the relative safety of the sea. Entanglement with fishing gear—active and discarded—is a primary reported cause of sea turtle injuries and death. Nutrient pollution from sewage and polluted runoff has been shown to drive the tumor-forming disease fibropapillomatosis, which is often fatal. Discarded plastics can kill turtles when they are mistaken for possible food or cause entanglement.
All of this has probably been a bit depressing. But there is an upside. Do you want to help our honu? You can. Ensure that fishing gear makes it back to shore and properly dispose of waste gear, especially used fishing lines. Make sure that trash ends up where it belongs. Recycle plastic whenever possible. Don’t disturb honu that come on shore to nest or rest (the rule is to stay at least 10 feet away). If you are more motivated, join a beach cleanup or volunteer to monitor beaches during nesting season to protect mama turtles and their nests.
If you want to go big, advocate for our honu and encourage legislation that supports actions to protect them. For a start, you can support coastal restoration and climate change mitigation. Voice your support for the control of feral animals along our coasts, from pigs to rats to cats, and help not just turtles, but also our endangered sea birds.
Ask legislators to expand recycling programs and keep plastics out of the ocean. Although there is much standing in the way of sea turtles making a full recovery, the fact that so many of the causes of sea turtle decline are human-based also means that we all have the opportunity to make a difference both on our own and as a community.
