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Hawksbill Sea Turtle
 Eretmochelys imbricata, or Honu 'Ea in Hawaiian, gets its common English name from its sharp beaklike mouth. This distinctive mouth helps to differentiate the hawksbill from other species of sea turtles.
DISTRIBUTION:
Hawksbill distribution is centered around tropical reef areas in the Atlantic, Pacific, and Indian Oceans. In the United States, nesting has been documented only in Hawaii and southern Florida. Fewer than 30 nesting hawksbill turtles exist in the Hawaiian Islands today, with primary nesting sites occurring around the island of Hawaii, and other nesting sites on the islands of Maui, Molokai, and Oahu.
COLOR:
Hawksbill turtles are well known for their beautiful carapace (exterior shell) often referred to as "tortoise shell" which was exploited for many years by the fashion industry. Although the color of the carapace varies from one geographical location to another, it is predominantly mottled brown with dark and light spots and streaks. The hawksbill sea turtle's underside is lighter yellow or white. This countershading helps camouflage the turtle from potential predators.
SIZE:
The hawksbill is a medium-sized sea turtle weighing up to around 270 pounds and growing to a carapace length of around 3-feet. Sea turtles start off as hatchlings weighing less than 1/2 ounce and having a carapace length of 1-1/2 inches. A single hatchling can easily fit into the palm of your hand. At sexual maturity a female turtle typically weighs around 130 pounds, with a carapace length averaging 2.5 feet long.
STATUS:
Hawksbill turtles are listed as an endangered species and are protected in Hawaii under state law, the Federal Endangered Species Act, and listed under the Convention on International Trade of Endangered Species, making it illegal to import or export turtle products. It is illegal to kill, capture, or harass sea turtles, or to handle them in any way without State and Federal permits.
FEEDING:
Juvenile, subadult and adult hawksbill turtles are omnivorous scavengers, feeding primarily on sponges found on the solid substrate of coral reefs. Analysis of stomach contents has also turned up sea anemones and assorted invertebrates. Unfortunately styrofoam and plastics have also been mistaken for food. The hawksbill's narrow, sharp beak is an excellent tool for foraging among coral crevices. The ledges and caves of reefs can also provide resting areas for the turtles throughout the day and night. Unlike the green sea turtles that often migrate several hundred miles between feeding and nesting grounds, hawksbills are often seen year-round on reefs near nesting sites. Little is known about the migration patterns of this rare species.
REPRODUCTION:
Males can be distinguished from females by their longer, thicker tail that extends well beyond the posterior part of the carapace. Mating often occurs at the surface in shallow waters near nesting beaches. Males will use their long heavy claws and tail to hold onto the females carapace. Copulation may last for several hours.
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LIFESPAN:
There are no documented longevity estimates for hawksbill turtles, although one hawksbill was known to be at least 32 years of age.
HATCHLINGS:
After an incubation period that ranges from 50-70 days, hatchlings will begin to emerge (from July to September in Hawaii), ususally at night when the sand temperature is cool, and predators (such as crabs, mongoose, rats, and fish) pose less of a threat. Emerging in small groups during the night, and sometimes over multiple evenings, hatchlings will immediately head toward the sea, attracted to the light of the moon and stars reflected off the ocean. Hawksbill hatchling mortality is high, resulting from physical challenges, disorientation from artificial lights, unregulated vehicle traffic on beaches, and predation. After safely reaching the water, hatchlings disappear to the open ocean and are seldom seen by humans until they reappear in coastal waters as juveniles.
NESTING:
At night, mostly between the months of May and October, nesting females will come ashore on small, isolated beaches to select a site for laying their eggs. Choosing a site beyond the high tideline and often underneath vegetation, solitary females will dig a body pit using their fore and hind flippers to excavate an egg chamber. After the last egg has been extruded, the female will refill the egg cavity with sand and immediately return to sea. Females only nest every two to three years, but can lay up to six clutches of eggs within one breeding season, at an average 15-21 day interval. Re-nesting females will often return to the same beach, sometimes within meters of previous nests. Each clutch contains from a few up to 230 small eggs (the average being about 130).
PREDATORS:
Historically humans have been the greatest predator of this sea turtle, killing it primarily for its highly prized "tortoise shell"- driving it almost to extinction. Today, most nesting populations are declining due to the exploitation and destruction of their nesting habitats. Beach development, shoreline and dune erosion, unregulated vehicle traffic onshore, and unregulated fishing and reef damaging activities can pose a significant threat to nesting turtles and their hatchlings. As adults, the greatest natural predator to turtles other than humans are sharks.
OTHER THREATS:
Marine debris is a threat to sea turtles. Sea turtles can become entangled in discarded netting. Dead sea turtles that have washed ashore have been found with plastics and other debris in their digestive system.
HOW YOU CAN HELP:
You can help protect these endangered sea turtles by not driving vehicles on the beach and by being careful where you walk during the nesting seasons! Walking through sand dunes near the vegetation line not only contributes to dune erosion, but can also disturb or trample nests.Reporting of turtle tracks, nesting activities, turtles basking on land, or injured or dead sea turtles is critical to the protection and management of this species. Please contact the Department of Land and Natural Resources, Division of Aquatic Resources at (808) 243-5294 or the U.S. Fish & Wildlife Service at (808) 875-1582. Mistreatment, harassment, or killing of sea turtles should be reported to the Enforcement Division of the National Marine Fisheries Service at (808) 541-2727 or on Maui, the State Division of Conservation and Resources Enforcement at (808) 984-8110. For more information on sea turtles call the Pacific Whale Foundation at (808) 879-8860.
You can also help by doing the following on a day-to-day basis:
- Participate in the nation-wide beach clean-up held every October.
- Don't litter.
- Help clean up our beaches.
- Dispose of your garbage properly.
- Don't take your groceries home in plastic bags.
- Purchase items in bulk instead of small, convenience sizes.
- Recycle (reuse) boxes, envelopes, news papers and packing materials.
- Purchase items packaged in cardboard or paper instead of plastic or styrofoam.
- Take cans, bottles, used motor oil, batteries and newspapers to recycling centers.
- Recycle stationery and paper by using the backs for lists and scratch paper.
- Buy recycled products.
- Hold onto your balloons!
FURTHER READING:
Balazs, G.H. 1976. Hawaiian Seabirds, Turtles, and Seals. World Wide Distributors: Honolulu, Hawaii.
Bjorndal, K.A. 1995. Biology and Conservation of Sea Turtles. Smithsonian Institution: Washington.
Jacobs, F. & A. Okimoto. 1995. Sea Turtles: Na Honu Kai. Hawaiian Islands National Marine Sanctuary with permission from the Center for Marine Conservation.
Witzell, W.N. 1983. Synopsis of Biological Data on the Hawksbill Turtle, Eretmochelys imbricata. Food and Agriculture Organization of the United Nations.
Compiled and presented as a Public Service by:
Pacific Whale Foundation, 300 Maalaea Rd., Ste. 211, Wailuku, Hawaii 96793
Toll-free: 1-800-942-5311
From Maui: 808-249-8811
May be duplicated in its entirety only for classroom use.
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