The Hawksbill Sea Turtle
The hawksbill sea turtle, Eretmochelys imbricata, is one of the smaller sea turtles of the Gulf of Mexico weighing only 95-165 lbs. (43-75 kg) as an adult and usually reaching a carapace (upper shell) length of 20-48 inches (50-120 cm). Hawksbills have a hawk-like beak, from which their name originates. Hawksbills are found worldwide in tropical and subtropical seas. They inhabit shallow coastal areas, lagoons, and coral reefs. In the western Atlantic they are found from New England to Brazil. Hawksbills are usually brown in color and are famous for their beautiful, ornate shells, which are dark amber with radiating streaks of brown or black. Their shells are also known as bekko or carey. The name "tortoise shell" was also given to their beautiful carapaces, which are made into many types of objects. Tortoise shell jewelry, combs, eyeglass frames, and tabletops are just a few examples. The killing of these turtles for their shells is the main reason for their decline. Shells would bring a price as high as $102 per pound ($225 per kg). In addition, the skin may be used for leather and oil for perfumes and cosmetics. Because of their commercial value, hawksbills are harvested in many places where they are found, despite laws to protect them. The hawksbill has been listed as an endangered species in the U.S. since 1970 and trafficking in hawksbill products in the U.S. is a federal crime. Most tortoise shell objects come from Cuba, Haiti, the Dominican Republic, and other islands in the Caribbean.
An interesting aspect of the hawksbill is its diet. Although omnivorous, hawksbills feed primarily on sponges and are one of the few vertebrates that do. Sponges are toxic to some marine creatures and they are unpalatable to many others because a large portion of the sponge body is composed of tiny, glass-like particles called spicules. Many creatures that feed on sponges have adaptations that protect them from spicules, however hawksbills do not. How they survive consuming the spicules and toxins is not fully understood. Consumption of sponge toxins may be the reason hawksbill flesh is poisonous in some regions. The fatality rate from eating hawksbill flesh is high and there are no known antidotes.
Hawksbills nest primarily at night, throughout the Gulf of Mexico and Caribbean. Their primary nesting areas in the U.S. are in Puerto Rico, the Virgin Islands, the southeast coast of Florida, and the Florida Keys. Unlike Kemp’s ridley sea turtles, which tend to nest in large groups, hawksbills prefer to nest alone or in small groups on isolated beaches. This is probably one reason the species has not already become extinct. Poachers are unable to systematically plunder eggs and shells in great numbers at once, as they can with other species. Hawksbills normally nest every second or third year producing 140-160 eggs per clutch and as many as five nests per season. Incubation takes from 55 to 70 days or longer.
On June 13, 1998 the first hawksbill nest recorded on the Texas coast was found at Padre Island National Seashore (Shaver, 1998). It contained 140 eggs of which 133 hatched and 132 hatchlings were released into the Gulf (one weak hatchling was taken to a rehabilitation facility). This remains the only hawksbill nest documented on the Texas coast.
Did You Know?
The Laguna Madre is one of only six lagoons in the world that is hypersaline (saltier than the ocean). More...