St John USVI Marine Life: Sea Turtles
Sea turtles are almost invariably a source of joy and excitement to the swimmers, snorkelers and divers fortunate enough to happen upon these gentle and magnificent creatures. Two species, the green turtle and the hawksbill turtle are commonly found around the Virgin Islands.
Hawksbills have a distinctive hawk-like beak and are usually found around reefs where they hunt crabs, fish, and snails or use their sharp bill to scrape sponges, tube worms and encrusting organisms off rocks and coral.
The giant leatherback turtle also inhabits our waters, but is almost extinct and rarely seen. The leatherback can grow to as much as eight feet in length and weigh over 1000 pounds. Leatherbacks are so-named because, instead of having a hard shell like other sea turtles, their backs are protected by layers of leather-like plates. Leatherbacks live in deep water and subsist on a diet of jellyfish. A major threat to the leatherback comes in the form of improperly disposed plastic bags, which the leatherback may easily mistake for a jellyfish. If consumed, the plastic bag will kill the turtle by clogging up its intestines.
Sea turtles have been in existence for about 150 million years, inhabiting the tropical and subtropical seas of the world.
Even though these large reptiles spend almost all their life in the sea, they are air breathers. They hold their breath just like we do when we dive without tanks. Fortunately for the sea turtles, they can hold their breath much longer than we can. They are excellent swimmers, possessing large flippers that can propel their streamlined bodies through the water quickly and gracefully.
Instead of teeth, sea turtles have a beak like a bird, (like a hawk in the case of the hawksbill turtle.) Sea turtles have no ears, which is probably just as well for creatures that spend their whole life diving. They can still hear, though, accomplishing this through the use of eardrums that are conveniently covered with skin. Sea turtles have a keen sense of sight while they are under the water, but are quite nearsighted when they stick their heads out of the water for their breath of air. The turtles also have an excellent sense of smell, which also functions best while they are submerged.
The female sea turtle comes ashore on secluded beaches at night to lay her eggs. She then covers the eggs up with sand and does her best to cover up any traces of her nocturnal activities. The mother turtle returns to the sea while the eggs incubate, a process that takes about eight weeks. When the eggs hatch, the baby turtles dig their way out of the sand and crawl slowly towards the sea. They are very vulnerable at this time. The tiny turtles are easy prey. Moreover they must avoid pitfalls such as getting trapped in holes in the sand, tangled up in seaweed, or having their way blocked by trash or other debris. They must reach the sea before the light of day exposes them to keen-eyed sea birds, mongooses, dogs and the baking hot tropical sun.
No one knows for certain what the hatchlings do next, but many scientists believe that the hatchlings then head out for the calm waters of the Sargasso Sea, which lies between the West Indies and the Azores in the middle of the Atlantic. Here they drift about hidden amidst the plentiful sargassum seaweed until they grow large enough to avoid most predators. The turtles then begin their long journey back to the beach where they were born. When the female reaches sexual maturity, sometime between 15 and 50 years depending on the species, she will lay her eggs on that beach.
The hawksbill, green and leatherback turtles are all listed as federally endangered species. Over-fishing and the commercial exploitation of hawksbills for tortoise shell products such as combs, hair barrettes, eyeglasses, picture frames and boxes have taken their toll on a once thriving population.
Sea turtles also face other serious problems. More and more beaches are being developed rendering them unsuitable for turtle nesting. Development also leads to an increase in the dog population. This is a problem because dogs are adept in finding and digging up turtle eggs. Furthermore it has been shown that mongooses do not instinctively hunt turtle eggs, but begin to do so after observing dogs engaged in this activity.
The awe and fascination that we experience upon an encounter with the sea turtle was shared by the cultures that inhabited these islands before us. To the spiritually evolved Taino people of the Caribbean, the turtle symbolized the ancestral mother and was a prominent feature in their religious art. This majestic and peaceful being cannot be allowed to become extinct. We must remember that we share our environment with all of God's creatures, and it is our responsibility to preserve and protect our unique heritage.