Turtles in the Hawaiian Islands
Sea turtles have graced our oceans for more than 75 million years. These ancient reptiles are among the most fascinating of all marine inhabitants. Here in Hawaii, three species of sea turtles are considered native: the green (Honu), the hawksbill (Honu’ea) and the leatherback. Two other species, the loggerhead and the olive ridley, are sometimes observed in Hawaiian waters.
The Hawaiian green sea turtle (Chelonia mydas) is the most common sea turtle in Hawaiian waters. It feeds on marine plants in shallow coastal waters throughout the Islands. Green sea turtles are primarily vegetarian and eat limu (algae) growing underwater on coral reefs and rocks in shallow waters. The upper shell (carapace) of the adult is dark with olive or gold flecks. Green turtles received their name from the color of their body fat. The honu grows to an adult breeding size of 200 pounds or more. Every 2-5 years, the adult Honu migrates hundreds of miles to mate and nest in the Northwestern Hawaiian Islands at isolated French Frigate Shoals.
Small numbers of the rare Hawksbill (Honu’ea) are found around the islands of Oahu, Molokai, Maui and Hawaii, where a few females have nested in recent years. Mature Hawksbills measure about three feet long and weigh up to 200 pounds. Hawksbills use their long, narrow beaks to probe for food. They feed on invertebrates, including sponges that are toxic to most other animals. The meat of the Honue’ea is poisonous to humans.
The Leatherback (Dermochelys Coriacea) is the world’s largest turtle and can grow up to eight feet long and weigh 2000 pounds. Leatherback turtles are seen in Hawaii’s deep offshore waters, where they feed on jellyfish and other invertebrates. Leatherbacks do not normally nest on Hawaii’s beaches, although a rare nesting was documented on Lanai in 1977. The Leatherback is the only sea turtle that lacks a hard shell. Fortunately, the laws in place to protect these marine species are effective and we are seeing an increase in the once dwindling numbers.
Viewing Hawai'i Wildlife
Ocean recreation in Hawai'i can include encounters with marine wildlife. For their protection and your safety, view them responsibly!
Sea turtles, monk seals, dolphins and whales are wild animals and protected under state and federal laws.
- View from a distance. Use binoculars or your camera's zoom for a close up.
- Do not disturb sea turtles or monk seals sleeping on the beach.
- Never touch, chase, or feed. Animals are wild, unpredictable and protected.
- Limit viewing time to a few minutes.
- Never swim with spinner dolphins - they rest and nurture their young during the day.
- View dolphins and whales from a boat or from shore.
- Sea Turtles: View from at least 10 feet (3 meters) - on land and in water.
- Hawaiian monk seals: Stay behind any signs or barriers. Stay back 50 feet (15 meters), if no barriers.
- Dolphins: Stay back at least 50 yeards (45 meters).
- Humpback whales: Do not approach within 100 yards - federal law.
When honu mature between the ages of 25-35 years, they begin to have the urge to breed. They leave their home reefs and swim to their birthplace for mating and nesting.
Between mid-March and mid-May, Laniakea honu begin their nesting migration to the Northwest Hawaiian Islands. Most honu have preferred East Island of the French Frigate Shoals in the past but Hurricane Walaka virtually destroyed the island in October 2018. Honu are very resilient and will adapt to the changed situation but it is yet to be determined where the majority of the individuals now displaced from their normal nesting island will choose to establish their nests in the future.
Not every mature honu will migrate, and the cycle of migration for any particular individual honu that does is irregular and unpredictable. Most wait from two to four years between nesting migrations, but there are exceptions. In fact, one of Laniakea's females, Olivia-Dawn, went 11 years between nesting migrations.
NOAA has tagged all of the adult honu basking at Laniakea with an ID chip so they can be identified both at their Laniakea foraging ground as well as at their nesting ground in the French Frigate Shoals. Over the years some honu have been tagged temporarily with a Time Depth Recorder (TDR), and some have been tagged with a satellite GPS. The TDR has provided data about the turtles’ dive depths, dive durations, ascent and descent rates, bottom time, and behavioral variables. The satellite tag provides data about migration routes.
The chart below tracked the 2010 migration of L-2, Hiwahiwa, when she made her second migration to East Island at the French Frigate Shoals. Hiwahiwa made a third migration in 2017 but had no tracking devices affixed to her carapace.
All maps and data provided by:
NOAA, National Marine Fisheries Service
Pacific Islands Fisheries Science Center
Links to current Sea Turtle Conservation News
NOAA researchers track a female green sea turtle's nesting journey after Hurricane Walaka washes away the primary nesting beach on East Island of the French Frigate Shoals..