Hawksbill Sea Turtle
Severely persecuted for "tortoiseshell" jewelry, this turtle derives its name from the hooked beak formed by its yellowish jaws. It is the only sea turtle with overlapping carapace scales (lacking when very young or very old). Hawksbill sea turtles have two pairs of prefrontal plates between the eyes. This distinctive mouth helps to differentiate the hawksbill from other species of sea turtles.
Hawksbill Sea Turtle - 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.
Hawksbill Sea Turtle - 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.
Hawksbill Sea Turtle - 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.
Hawksbill Sea Turtle - Status:
Hawksbill sea 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.
Hawksbill Sea Turtle - Feeding:
Juvenile, subadult and adult hawksbill sea 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.
Hawksbill Sea Turtle - 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.
Hawksbill Sea Turtle - Lifespan:
There are no documented longevity estimates for hawksbill sea turtles, although one hawksbill was known to be at least 32 years of age.
Hawksbill Sea Turtle - 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.
Hawksbill Sea Turtle - 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).
Hawksbill Sea Turtle - 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.
Hawksbill Sea Turtle - Status:
Hawksbill sea turtles are protected in the U. S. under the Endangered Species Act. They are still exploited overseas. Problems facing hawksbill sea turtles include over-exploitation for meat, eggs and whole young animals. Various parts of the body are also used for leather, oil, perfume and cosmetics. However, the greatest threat is the continuing demand for "tortoiseshell." The shell is used for medicinal purposes, as well as for modern day articles of jewelry. The high prices obtained for the shell thwart attempts to protect this sea turtle. A shell can sell for $50 to $60 per pound. In Japan, where the market is incredibly high, a shell might sell for up to $100 per pound! Immature stuffed specimens of this species are also popular. In Singapore and the Philippines, 32,000-105,000 stuffed hawksbills are sold annually.
Management and Research Needs
During summer migrations, sea turtles are known to migrate into more temperate waters, sometimes extending as far north as Labrador. Although nesting does not occur on Long Island, they will occasionally become stranded on or near the shore. In order to aid those animals that may still be alive and to facilitate the timely and efficient handling of carcasses, a Stranding Network was established in 1980 through the cooperation of the New York State Department of Environmental Conservation and the National Marine Fisheries Service. Through this system, strandings can be reported via a hotline; the number is (516) 369-9829. Marine biologists from the Riverhead Foundation for Marine Research and Preservation handle stranded and dead specimens.
In response to sea turtle mortality in trawl nets, the National Marine Fisheries Service has issued regulations requiring shrimp trawlers on the southeastern and Gulf coasts to have a turtle excluder device (TED) on their nets. This device allows turtles and other large marine life to escape should they enter a net.
Hawksbill Sea Turtle - Economical and Biological uses:
Hawksbill Sea Turtles have served a wide range of important functions to Pacific Islanders. The shell of this species has been described as the "world's first plastic" and has served a wide variety of ornamental and practical uses. The bones were fashioned to make tools. Various body parts were used to make medicine. The flesh and eggs provided food.