There are two turtle families (Cheloniidae and Demochelydae), five genera and eight known living species of sea turtles. They are differentiated by their flattened forelimbs, each with a single claw. Freshwater turtles have five easily distinguishable claws on each forelimb. Of the eight remaining species of marine turtles in the world, six are found in the Philippines. The UNESCO World Heritage considers the Turtle Islands in the Philippines as the only major nesting ground, hosting more than 1,000 annual nesters of the giant Green Turtles (Chelonia mydas) in the whole ASEAN region.
The Turtle Islands (Kalayaan Group of Islands) atolls in the South China Sea and is being claimed by several countries including the Philippines. The marine turtles found in the different islands in the Philippines and the Indo-pacific region are the green sea turtle, the loggerhead, hawksbill, the leatherback, the olive Ridley, and the flatback. Most of these species are migratory, crossing vast distances of tropical and subtropical oceans to and from their nesting and feeding grounds. Once, a loggerhead turtle from Yakushima Island, Japan, was captured off Pilas Island in Basilan, about 3,000 kilometers away.
Well-adapted to life in the sea, marine turtles can dive for long periods of time and swim powerfully. The leatherback turtle, the largest of the sea turtles, is capable of diving at depths exceeding 1,200 meters. The leatherback, called kantuhan in Palawan, Philippines and manahanga in Sulu and Tawi-Tawi, got its name from its leathery covering which distinguishes it from its hard-shelled relatives.
Marine turtles have no teeth and use a sharp, bony beak and jaws to tear and bite their food. They feed mostly on jellyfishes, crabs, shrimps, fishes, algae, and sea grasses. Their senses of sight, taste and touch are well developed. Due to the absence of vocal cords, the only sounds they can make are hissing and grunting noises while exhaling during courtship and mating.
Nestling turtles lay eggs of different number and size per nest according to species. Hawksbill turtles lay 50 to 250; loggerheads and olive Ridleys lay an average of 120; leatherbacks lay 85 to 120; and green sea turtles lay 40 to 190 eggs per nest. The eggs are leathery and resemble white ping pong balls. It takes 52 to 62 days before they hatch. Throughout the incubation period, the eggs are preyed upon by monitor lizards, crabs, birds, rodents, stray cats and dogs. But the most ravenous predator is human.
The hatchlings’ first year of life is planktonic or “free swimming.” Offshore, they are preyed upon by fish and other marine creature. Those who survive migrate to some unknown habitat. Marine herpetologists call this stage the “lost years.” Upon reaching sexual maturity, they will return to their birth place, guided by a mysterious instinct, to start reproducing. Less than 1% of the hatchlings that emerge from the nest will survive to reach adulthood. And because of man-made intrusions in the life cycle, less than 1% live up to the reproductive stage. Sea turtles are classified by the International Union for Conservation of Nature (IUCN) as “endangered.” Conservationist groups have been established to protect these species from becoming extinct. In the Philippines, an administrative order was issued prohibiting the capture and trade of marine turtles or any of its by-products.
Although the green sea turtle is the most abundant among the six species found in the Philippines, its number continues to decrease. Conservationists have seen alarming percentages of decline in the population of marine turtles—the main cause of decline is man-made. Turtles are hunted in the sea or slaughtered on the beach while they lay their eggs. Their meat and eggs are taken as food, while their skin and shells are processed into various by-products such as jewelry.
The hawksbill’s carapace is highly priced as tourist souvenirs whether stuffed or made into novelty items such as bangles, combs, and jewelry boxes. Thousands of these species are slaughtered yearly. Its population decline has been recorded at 80% as of 2009. Today the population of sea turtles remains in dangerously low levels. It is saddening that these beautiful creatures are being slaughtered just for money.