Hawaii’s Sea Turtles
Five of the world’s 7 species of sea turtles make their home in Hawaii’s waters, including the Green Sea Turtle (honu), hawksbill (honu‘ea), leatherback, loggerhead, and olive ridley. The green sea turtle is by far the most commonly encountered sea turtle on Hawaiian reefs, followed by the hawksbill. Olive ridley, leatherback, and loggerheads are typically found in deeper, offshore waters and are rarely seen by the average ocean-goer. On Maui, sea turtles are a favorite of snorkelers and divers on the island’s South and West coastlines.
Recently, Hawaiian Paddle Sports guides caught this RARE footage of an endangered hawksbill sea turtle feasting on a frog fish off the Maui coastline.
Snorkeling with Maui Sea Turtles
While marine species are often unpredictable, turtle sightings are guaranteed for tours at our South Maui Turtle Town location. While snorkeling in Maui, you can often spot green sea turtles lying on the ocean floor, eating algae, visiting their local ‘turtle cleaning station’. Sea turtles usually come up to the surface to breath, and can also be found on Hawaii beaches basking and resting. When swimming with sea turtles in Maui, remember to keep your arms at your side and remain at least 15 feet from turtles. Harassing sea turtles in any way is illegal in the state of Hawaii. Violators can be fined up to $100,000 per violation and receive jail time for interference with the turtle population.
The Life of Sea Turtles
Sea turtles have been around for more than 150 million years, long enough to watch dinosaurs evolve and go extinct. As marine reptiles, sea turtles spend the majority of their lives traveling the open ocean, with females coming ashore only to lay their eggs. They are expert navigators and often migrate thousands of miles between feeding grounds and nesting beaches.
Every sea turtle starts out as a small egg, about the size of a ping pong ball. Once eggs are laid, they will incubate in the sand for about 60 days before hatching. Baby sea turtles, known as “hatchlings”, typically emerge from the nest at night to make their way to the ocean. Before even reaching the water’s edge, hatchlings are easy prey for sea birds, crabs, rats, cats, dogs, and mongoose. Once in the ocean, they face a whole new host of challenges, including fish, sharks, and humans. In fact, scientists estimate that only 1 out of every 5,000 hatchlings will reach adulthood.
The first few years of a sea turtle’s life (from ages 3-7) is spent in the open ocean. Scientists have dubbed this period the “Lost Years”, as they are unsure of where the juvenile turtles actually go or what they do. For Hawaii-born turtles, these juveniles will eventually return to the protected shoreline areas of the Hawaiian archipelago to live out the rest of their lives. Sea turtles are long-lived species, and do not reach sexual maturity until about 25 years of age. It is not known how long a sea turtle can live, but scientists estimate that green sea turtles can live at least 80 years.
Hawaiian Green Sea Turtles
The most common sea turtle species in Hawaii is by far the Hawaiian green sea turtles (honu). They are regularly found resting in underwater ledges, basking on beaches, and nibbling on algae in shallow waters. The average adult Hawaiian green sea turtle is 4-5 feet long and weighs 250 pounds, although they can grow as large as 500 pounds.
Despite their name, green sea turtles do not actually appear “green” – at least from the outside. Instead, the name “green” comes from the color of their internal fat tissue, which is green due to a diet that primarily consists of algae. Green sea turtles are commonly seen calmly cruising Maui’s reefs, but when spooked can reach speeds of up to 20 miles per hour.
In addition to feeding and resting, honu in Hawaii also be observed basking on select beaches on both Maui and Hawaii Island. This behavior, thought to be a way to conserve energy or boost body temperature, has only been witnessed in Australia, the Galapagos Islands and Hawaii.
More than 90% of Hawaiian green sea turtles migrate more than 1,000 miles northwest to the French Frigate Shoals in the Northwestern Hawaiian Islands to mate and nest every 2 to 5 years. Females lay 3 to 6 clutches per nesting season, each of which contains approximately 100 eggs.
Male and female honu can both be found in the Main Hawaiian Islands, and are distinguished by the length of their tails. Males have a longer, thicker tail that extends past their back flipper, in addition to a more evident claw on each of flipper, which is typically used for holding their position during mating.
Hawksbills in Hawaii
Hawksbills are named for their sharp, “hawk-like” beak that is used to extract food, particularly sponges, from the crevices of coral reefs. In addition to sponges, hawksbill also dine on marine algae, squid, sea urchins, shrimp, fish, and jellyfish. They are considered one of the smaller species of sea turtles, reaching up to 3 feet in length and and 150 pounds.
In Hawaii, hawksbills nest exclusively in the Main Hawaiian Islands, with estimates placing the number nesting females at fewer than 100 individuals. Nesting takes place on Maui, Molokai, and Hawaii Island, but over 90% of hawksbill nesting activity has been recorded on the Ka`u coastline of Hawaii Island. Over the past 20 years, Oneloa Beach Park (aka “Big Beach”) has been a top site for hawksbill nesting on Maui. However only a handful of females are known to nest specifically on Maui’s beaches.
As with the honu, hawksbill nest every 2-3 years and lay between 3-6 clutches per nesting season, averaging 180 eggs per clutch. Nesting can begin as early as May and lasts until October, although hatchlings can emerge as late as December.
Unfortunately, hawksbills are considered a critically endangered species throughout most of their habitat. They are still harvested in many parts of the world for their prized shells, which are used to make decorative items and jewelry. Nests are also often poached for eggs. In Hawaii, hawksbills are much less commonly seen than honu, and despite similar protections, have no experienced the same population rebound.
Honu or Hawksbill?
To an untrained eye, hawksbill and green sea turtles can look very similar. There are, however, a few insider ways to tell the difference between the two.
- The first clue is the turtle’s jaw and head. Hawksbills have a smaller head than green sea turtles, and their jaws are more pointed and beaklike.
- Still looking at a sea turtle’s head, count the number of “scutes” (or scales) that are between the sea turtle’s eyes. Hawksbills have 2 pairs of pre-frontal scutes (for a total of 4 scutes), while green sea turtles only have 1 pair.
- The carapace (or shell) of greens and hawksbills also differ. The scutes overlap on hawksbills, and the edges of their carapace are serrated. Green sea turtles do not have overlapping scutes, and carapace edges are smooth.
- Hawksbill have 2 claws on each front flipper, whereas green sea turtles only have 1 claw on each flipper.
Keep in mind, though, that 99.99% of the sea turtles that you’ll see while snorkeling or diving on Maui will be green sea turtles.
Hawaii Sea Turtle History
Sea turtles have played an important role in Hawaiian culture for hundreds of years. Both honu and honu`ea are mentioned in the Kumulipo, the Hawaiian creation chant. Sea turtles were utilized in traditional ceremonies and some families considered them aumakua (family spirits). Turtles were also used for many everyday purposes – tools, jewelry, utensils, containers, medicine, and food, among others. The harvesting of sea turtles and turtle eggs was carefully controlled by local chiefs and the kapu system.
Sea Turtle Threats
Once considered in real danger of extinction, Hawaiian green sea turtles have seen a dramatic increase in population under the protection of the U.S. Endangered Species Act. Over the last 25 years, Hawaii’s honu population has increased as much as 53%. Hawaii’s hawksbill population has not fared as well, and continues to remain a critically endangered species.
Still, Hawaii’s sea turtles, like many sea turtle populations around the world, continue to face a number of threats. Not only do sea turtle hatchlings face a number of threats both on land in the water, but juvenile and adult turtles must contend a number of challenges including:
- Coastal development along Hawaii’s coastline threatens to reduce the amount of suitable beach area for turtle nesting and basking.
- Entanglement in debris like fishing line or ingestion of plastic pieces can severely injure or kill turtles. One of the biggest ways that you can help sea turtles is by reducing your consumption of single-use plastics like straws, cutlery, and takeout containers.
- Polluted runoff and high inputs of nutrients from fertilizers results in poor water quality. Fibropapilloma virus has been potentially linked to polluted water.
For more information about sea turtles in Hawaii, check out Hawaii Wildlife Fund or Hawaii Hawksbills. During hawksbill nesting season, Hawaii Wildlife Fund keeps round-the-clock watch on hawksbill nests to ensure that the greatest number of hatchlings are able to reach the ocean for a shot at survival. Hawaii Hawksbills also promotes sea turtle science, education, and conservation in the Hawaiian Islands.