Sea Turtles
By Claudia Lombard
Sea turtles are among the largest living reptiles. They spend almost their entire lives at sea, have scales and a bony shell (except leatherbacks), are cold blooded, breathe air, and lay their eggs on land. The earliest known sea turtle fossil dates back to 150 million years ago! St. Croix is home to four species of sea turtle. The leatherback, hawksbill, green and loggerhead sea turtle are found nesting on the beaches and swimming in the waters of the U.S. Virgin Islands.
Leatherback sea turtles are the largest sea turtle; females nesting on St. Croix average 6-800 lbs and the largest male ever recorded was more than 2000 lbs! After nesting in the tropics, leatherbacks migrate to the North Atlantic; a satellite transmitter was attached to a St. Croix nester and she was documented traveling all the way to Nova Scotia! Scientists have estimated that leatherbacks could be extinct within 10 to 15 years based on current levels of population decline.
Hawksbill sea turtles are named for the birdlike shape of their beak which helps tear off their favorite food item - sea sponges. They are the smallest sea turtle found in the USVI weighing in at about 150 pounds. Hawksbills have been documented nesting on almost all of the 52 beaches in St. Croix. Hawksbills were traditionally harvested for their beautiful shells which have been used to make jewelry and other luxury items. Green sea turtles are herbivores and mostly graze on sea grass. The carapace (shell) of greens is not green but their vegetarian diet causes their internal fat to become greenish in color.
Green turtles have been documented holding their breath for up to five hours - this is at a resting state. Loggerhead sea turtles are named for their relatively massive, block-like head.
Loggerheads are the most common nesting sea turtle in the southeastern U.S. but are very rarely seen in the USVI.
During the peak nesting season, which in the USVI occurs between March and October female turtles crawl ashore to lay their eggs on our sandy beaches. Females use their front flippers to excavate body pits and fling the upper layer of dry sand away. Next, with their bodies in this pit, they use their rear flippers to dig an egg chamber in the moist sand. Depending on the species, the female will deposit approximately 80 to 150 eggs into the chamber, cover the eggs with sand and return to the sea.
The eggs incubate in the sandy nest for approximately 2 months. The sea turtle hatchlings crawl to the surface of the sand and then when the sunsets and the sand cools the hatchlings race to the sea. As adults, hatchlings have very few predators but as hatchlings they are very susceptible to many terrestrial and marine predators. Hatchlings spend several days swimming far offshore to drift lines where they can rest, eat and grow.
All four sea turtle species found nesting on the beaches and swimming in the waters of the U.S. Virgin Islands are designated as threatened or endangered and are protected by the Endangered Species Act. Some of the more serious threats facing sea turtles include loss of nesting habitat to coastal development, poaching of sea turtles and their eggs, artificial lighting on or adjacent to beaches, incidental take of turtles during commercial fishing activities, ingestion of and entanglement in marine debris, and beach erosion and increased sand temperatures caused by climate change.
