Thursday, December 22, 2011

Turtles of Pacific Ocean

Micronesia Post issued the stamp set features Turtles of Pacific Ocean in many type of issuance, one souvenir sheet, 4  postage stamps, and one miniature sheet consist of 4 postage stamps. The species of turtle depicted are Green Sea Turtle, Hawksbill Turtle, Loggerhead Turtle, Australian Flatback Turtle, Kemp’s Ridley Turtle, Olive Ridley turtle, Leatherback Turtle.
Green Sea Turtle – $ 1.56
The Green Sea Turtle or Chelonia mydas is a sea turtle, possessing a dorsoventrally flattened body covered by a large, teardrop-shaped carapace and a pair of large, paddle-like flippers. It is usually lightly colored, although parts of the carapace can be almost black in the eastern Pacific.  Chelonia mydas is mostly herbivorous. The adults commonly inhabit shallow lagoons, feeding mostly on various species of sea grasses.
Chelonia mydas has a dorsoventrally flattened body, a beaked head at the end of a short neck, and paddle-like arms well-adapted for swimming.Adult green turtles grow to 1.5 metres long. While individuals have been caught that reached weights of up to 315 kilograms , the average weight of mature individuals is 110–190 kilograms . The largest known Chelonia mydas weighed 395 kilograms .
Hawksbill Turtle – $ 1.56
The Hawksbill  turtle (Eretmochelys imbricata) is a critically endangered sea turtle belonging to the family Cheloniidae. Eretmochelys imbricata is easily distinguished from other sea turtles by its sharp, curving beak with prominent tomium, and the saw-like appearance of its shell margins.
It has a generally flattened body shape, a protective carapace, and flipper-like arms, adapted for swimming in the open ocean.  Hawksbill shells slightly change colors, depending on water temperature. While this turtle lives part of its life in the open ocean, it spends more time in shallow lagoons and coral reefs.

Loggerhead Turtle – 95 c
The loggerhead turtle is found in the Atlantic, Pacific, and Indian oceans as well as the Mediterranean Sea. It spends most of its life in saltwater and estuarine habitats, with females briefly coming ashore to lay eggs.
The loggerhead  turtle has a low reproductive rate; females lay an average of four egg clutches and then become quiescent, producing no eggs for two to three years. The loggerhead reaches sexual maturity within 17–33 years and has a lifespan of 47–67 years.
The loggerhead sea turtle is omnivorous, feeding mainly on bottom dwelling invertebrates. Young loggerheads are exploited by numerous predators; the eggs are especially vulnerable to terrestrial organisms. Once the turtles reach adulthood, their formidable size limits predation to large marine organisms such as sharks.
Loggerheads are considered an endangered species and are protected by the International Union for the Conservation of Nature. Untended fishing gear is responsible for many loggerhead deaths. Turtles may also suffocate if they are trapped in fishing trawls.
Hawksbill Turtle – 22 c
Adult hawksbill sea turtles have been known to grow up to 1 metre  in length, weighing around 80 kilograms  on average. The heaviest hawksbill ever captured was measured to be 127 kilograms . The turtle's shell, or carapace, has an amber background patterned with an irregular combination of light and dark streaks, with predominantly black and mottled brown colours radiating to the sides.
Human fishing practices threaten Eretmochelys imbricata populations with extinction. The World Conservation Union. classifies the Hawksbill as critically endangered.Hawksbill shells are the primary source of tortoise shell material, used for decorative purposes.
Green Sea Turtle – $ 2.80
Green Sea Turtle or Chelonia mydas migrate long distances between feeding grounds and hatching beaches. Many islands worldwide are known as Turtle Island due to green sea turtles nesting on their beaches. Females crawl out on beaches, dig nests and lay eggs during the night. Later, hatchlings emerge and walk into the water. Those that reach maturity may live to age 80 in the wild. Chelonia mydas is listed as endangered by the IUCN and CITES and is protected from exploitation in most countries
Australian Flatback Turtle – 88 c
The flatback sea turtle (Natator depressus) is a sea turtle that is endemic to the continental shelf of Australia. Flatback turtles belong to the Cheloniidae, or sea turtle, superfamily and are the only species found in the genus Natator.
The carapace of the adult is on average 90 centimeters  long. It is low domed, the edge is upturned and has four pairs of costal scales—fewer than other marine turtles. The upper parts are an olive-grey, while it is more pale ventrally. A single pair of scales are located at the front of the head,
Flatback turtles are usually found in bays, shallow, grassy waters, coral reefs, estuaries and lagoons on the northern coast of Australia and off the coast of Papua New Guinea.
The species may feed off Indonesia and Papua New Guinea, but it nests only in Australia. Nesting occurs across the top half of Australia, from Exmouth in Western Australia to Mon Repos Conservation Park in Queensland.
The most significant breeding site is Crab Island in the western Torres Strait. Breeding may also occur on the islands of the southern Great Barrier Reef, and on mainland beaches and offshore islands north of Gladstone.


Kemp’s Ridley Turtle – 98c (top row)
Kemp's ridley sea turtle (Lepidochelys kempii), or Atlantic ridley sea turtle is the rarest sea turtle and is critically endangered. It is one of two living species in the genus Lepidochelys (the other one being L. olivacea the olive ridley turtle).
Kemp's ridley is a small living sea turtle species, reaching maturity at (61–91 cm) long and averaging only 45 kilograms .Typical of sea turtles, it has a dorsoventrally depressed body with specially adapted flipper-like front limbs.
The Kemp's ridley turtle feeds on molluscs, crustaceans, jellyfish, algae or seaweed, and sea urchins.Kemp's ridley sea turtles generally prefer warm waters but inhabit waters as far north as New Jersey, 
Leatherback Turtle – 98c (second row)
The leatherback sea turtle (Dermochelys coriacea) is the largest of all living sea turtles .its carapace is covered by skin and oily flesh. Dermochelys coriacea is the only extant member of the family Dermochelyidae.
Leatherback turtles have the most hydrodynamic body design of any sea turtle, with a large, teardrop-shaped body. A large pair of front flippers power the turtles through the water.
The leatherback's flattened forelimbs are adapted for swimming in the open ocean. Claws are absent from both pairs of flippers. The leatherback's flippers are the largest in proportion to its body among extant sea turtles. Leatherback's front flippers can grow up to 2.7 metres  in large specimens, the largest flippers (even in comparison to its body) of any sea turtle.
Loggerhead Turtle – 98 c (third row)
Same as described in other issue stamps –95c.
Olive Ridley Turtle – 98c (fourth row)
The olive ridley  turtle (Lepidochelys olivacea), is a species of sea turtle,has a cirumtropical distribution living in tropical and warm waters of the Pacific and India Oceans from India, Arabia, Japan, and Micronesia south to southern Africa, Australia, and New Zealand.
The olive ridley is a small extant sea turtle, with an adult carapace length averaging 60 to 70 cm.The olive ridley is predominantly carnivorous, especially in immature stages of the life cycle. .
Animal prey consists of protochordates or invertebrates, which can be caught in shallow marine waters or estuarine habitats. Common prey items include jellyfish, tunicates, sea urchins, bryozoans, bivalves, snails, shrimp, crabs, rock lobsters, and sipunculid worms. The olive ridley is also known to feed on filamentous algae in areas devoid of other food sour
Known predators of olive ridley nests include raccoons, coyotes, feral dogs and pigs, opossums, coatimundi, caimans, ghost crabs, and the sunbeam snak.The olive ridley sea turtles are considered the most abundant, yet globally they have declined by more than 30% from historic levels. These turtles are considered endangered because of their few remaining nesting sites in the world.

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