The Ocean King
Saturday 21 August 2010
Saturday 27 February 2010
Sunday 25 January 2009
Saturday 10 January 2009
The Sea Turtle -it's beautiful life of wave and sun
Sea Turtles (superfamily Chelonioidea) are turtles found in all the world's oceans except the Arctic Ocean. There are seven living species of sea turtles: flatback ,green sea turtle, hawksbill , Kemp's Ridley , leatherback , loggerhead and olive ridley. The East Pacific subpopulation of the green turtle was previously classified as a separate species, the black turtle, but DNA evidence indicates that it is not evolutionarily distinct from the green turtle. All species except the leatherback are in the family Cheloniidae; the leatherback belongs to the family dermochelyidae and is its only member.
Although they have been around for tens of millions of years since the Mesozoic, the body plan of sea turtles has remained relatively constant. Sea turtles possess dorsoventrally-flattened bodies with two hind legs and highly-evolved paddle-like front arms.
Different species are distinguished by varying anatomical aspects: for instance, the prefrontal scales on the head, the number of and shape of scutes on the carapace, and the type of inframarginal scutes on the plastron. The leatherback is the only sea turtle that does not have a hard shell, instead carrying a mosaic of bony plates beneath its leathery skin. It is the largest of the sea turtles, measuring six or seven feet (2 m) in length at maturity, and three to five feet (1 to 1.5 m) in width, weighing up to 1300 pounds (650 kg). Other species are smaller, being mostly two to four feet in length (0.5 to 1 m) and proportionally narrower.
Sea turtles spend almost all their lives submerged but must breathe air for the oxygen needed to meet the demands of vigorous activity. With a single explosive exhalation and rapid inhalation, sea turtles can quickly replace the air in their lungs. The lungs are adapted to permit a rapid exchange of oxygen and to prevent gasses from being trapped during deep dives. The blood of sea turtles can deliver oxygen efficiently to body tissues even at the pressures encountered during diving. During routine activity green and loggerhead turtles dive for about 4 to 5 minutes and surface to breathe for 1 to 3 seconds.
Sea turtles possess a salt excretory gland at the corner of the eye, in the nostrils, or in the tongue, depending upon the species; chelonian salt glands are oriented in the corner of the eyes in leatherback turtles. Due to the iso-osmotic makeup of jellyfish and other gelatinous prey upon which sea turtles subsist, sea turtle diets are high in salt concentrations and chelonian salt gland excretions are almost entirely composed of sodium chloride1500-1800 mosmoll-1 (Marshall and Cooper, 1988; Nicolson and Lutz, 1989; Reina and Cooper, 2000). Turtles can rest or sleep underwater for several hours at a time but submergence time is much shorter while diving for food or to escape predators. Breath-holding ability is affected by activity and stress, which is why turtles drown in shrimp trawls and other fishing gear within a relatively short time.
The superfamily Chelonioidea has a worldwide distribution; sea turtles can be found in all oceans except for in the polar regions. Some species travel between oceans. The Flatback turtle is found solely on the northern coast of Australia.
Sea turtles are highly sensitive to the Earth's magnetic field and use it to navigate. The longevity of sea turtles has been speculated at 80 years. The fact that most species return to nest at the locations where they were born seems to indicate an imprint of that location's magnetic features.
The Ridley turtles are especially peculiar because instead of nesting individually like the other species, they come ashore in one mass arrival known as an "arribada" (arrival). With the Kemp's Ridley this occurs during the day. Their numbers used to range in the thousands but due to the effects of extensive egg poaching and hunting in previous years the numbers are now in the hundreds.
After about 30 years of maturing, adult female sea turtles return to the land to nest at night, usually on the same beach from which they hatched. This can take place every two to four years in maturity. They make from four to seven nests per nesting season.
All sea turtles generally employ the same methods when making a nest. A mature nesting female hauls herself onto the beach until she finds suitable sand on which to create a nest. Using her hind flippers, the female proceeds to dig a circular hole 40 to 50 centimeters deep. After the hole is dug, the female then starts filling the nest with a clutch of soft-shelled eggs one by one until she has deposited around 150 to 200 eggs, depending on the turtle's species. The nest is then re-filled with loose sand by the female, re-sculpting and smoothing the sand over the nest until it is relatively undetectable visually. The whole process takes around thirty minutes to a little over an hour. After the nest is laid, the female then returns to the ocean.
Some of the eggs are unfertilized and the rest contain young turtles.Incubation takes about two months. The length of incubation and the gender of the hatchling depends on the temperature of the sand. Darker sands maintain higher temperatures, decreasing incubation time and increasing the frequency of female hatchlings. When the time comes, these hatchlings tear their way out of their shells with their snout and once they have reached the surface of the sand, they will instinctively head towards the sea. Only a very small proportion of them (usually .01%) will be successful, as many predators wait to eat the steady stream of new hatched turtles (since many sea turtles lay eggs en masse, the eggs also hatch en masse).
The hatchlings then proceed into the open ocean, borne on oceanic currents that they often have no control over. While in the open ocean, it used to be the case that what happened to sea turtle young during this stage in their lives was unknown. However in 1987, it was discovered that the young of Chelonia mydas and Caretta caretta spent a great deal of their pelagic lives in floating sargassum beds - thick mats of unanchored seaweed floating in the middle of the ocean. Within these beds, they found ample shelter and food. In the absence of sargassum beds, turtle young feed in the vicinity of upwelling "fronts". In 2007, it was verified that green turtle hatchlings spend the first three to five years of their lives in pelagic waters. Out in the open ocean, pre-juveniles of this particular species were found to feed on zooplankton and smaller nekton before they are recruited into inshore seagrass meadows as obligate herbivores.
Like many other animals in the world, sea turtles have predators. An example of natural protection is their shell. Other protections include the ability of some species' massive jaws to suddenly snap shut, and to stay underwater for hours on end; these are both instinctual and natural. Turtles have many senses to aid them in the sea. Sea turtle ears have a single bone in the middle ear that conducts vibrations to the inner ear. Researchers have found that sea turtles respond to low frequency sounds and vibrations. Sea turtles have an extremely good eyesight in water but are shortsighted on land. Under experimental conditions, the loggerhead and green sea turtle hatchlings showed a preference for ultraviolet, blue-green and violet light. Sea turtles are touch-sensitive on the soft parts of their flippers and on their shell. Most researchers' theories portray that sea turtles have an acute sense of smell in the water. Their experiments showed that the hatchlings reacted to the scent of shrimp. This sense allows sea turtles to locate food in deep and murky water. Sea turtles open their mouths a bit and draw in water through the nose, then immediately empty it out again through the mouth. Pulsating movements of the throat are thought to be associated with smelling. Sea turtles have very hard shells. Sea turtles are many different colors like blue green and light violet. Sea turtles flippers are very soft and sensitive.
Marine turtles are caught worldwide, despite it being illegal to hunt most of the species in many countries. A great deal of intentional marine turtle harvests worldwide are for the food industry. In many parts of the world, the flesh of sea turtles are considered fine dining. Texts dating back to the fifth century B.C. describes sea turtles as exotic delicacies in ancient China. Historically, many coastal communities around the world have depended on sea turtles as a source of protein. Several turtles could be harvested at once and kept alive on their backs for months until needed. The skin of the flippers are also prized for use as shoes and assorted leather-goods.
To a much lesser extent, specific species of marine turtles are targeted not for their flesh, but for their shells. Tortoisehell, a traditional decorative ornamental material used in Japan and China, is derived from the carapace scutes of the hawksbill turtle. The use of marine turtle shells for decorative purposes is by no means limited to the orient. Since ancient times, the shells of sea turtles (primarily the hawksbill) have been used by the ancient Greeks and ancient Romans. Various articles and ornaments used by the elite of these societies, such as combs and brushes, were from processed turtle scutes. The Moche people of ancient Peru worshipped the sea and its animals. They often depicted sea turtles in their art.
All species of sea turtles are listed as threatened or endangered. The leatherback, Kemp's ridley, and hawksbill turtles are listed as critically endangered. The olive ridley and green turtles are considered endangered, and the loggerhead is a threatened species. The flatback's conservation status is unclear due to a lack of research data.
Sea turtles used to be hunted on a large scale in the whaling days for their meat, fat and shells. Coastal peoples have also been known to gather turtle eggs for consumption. One of their most significant threats now comes from bycatch due to various fishing methods,long-line fishing has been blamed as one of the causes of accidental sea turtle deaths, and the black market demand for tortoiseshell for both decoration and supposed health benefits.
Nets used in shrimp trawling and fishing have been known to cause the accidental deaths of sea turtles. The turtles, as air-breathing reptiles, must surface to breathe. Caught in a fisherman's net, they are unable to go to the surface to breathe and suffocate to death in the net. In early 2007, almost a thousand sea turtles were killed inadvertently in the Bay of Bengal over the course of a few months as a result of becoming trapped in fishing nets.
However some relatively inexpensive changes to fishing techniques, such as slightly larger hooks and traps from which sea turtles can escape, can dramatically cut the mortality rate.Turtle Excluder Devices (TEDS) have reduced sea turtle bycatch in shrimp nets by 97 percent. Another danger comes from marine debris, especially from abandoned fishing nets in which they can become entangled.
Beach development is another area which poses threats to sea turtles. Since sea turtles return to the same beach locations to nest, if these areas are developed they may be left with nowhere to nest, or their nesting locations may be threatened by human activity. Therefore, there has been a movement to protect these areas, in some cases by special police. In some areas, such as the east coast of Florida, after the adult turtles lay their eggs, they are dug up and relocated to special fenced nurseries where they can be protected from beach traffic. This is not the best thing to do, as many turtle species return to the beach on which they were born. Hatchlings find their way to the ocean by crawling towards the brightest horizon, but often become disoriented on developed stretches of coastline. Special lighting ordinances may also be enforced to prevent lights from shining on the beach and confusing young hatchlings, causing them to crawl towards the light and away from the water, usually crossing a road. A turtle-safe lighting system uses red light in place of white light as sea turtles can't see red light.
Another major threat to sea turtles is the black market trade in eggs and meat. This is a pervasive problem throughout the world, but especially a concern in the Philippines, India, Indonesia and throughout the coastal nations of Latin America. Estimates are as high as 35,000 turtles killed a year in Mexico and the same number in Nicaragua. Conservationists in Mexico and the United States have launched "Don't Eat Sea Turtle" campaigns in order to reduce the urban black market trade in sea turtle products. These campaigns have involved figures such as Pope John Paul II,Dorismar,Los Tigres del Norte and Mana. Sea turtles are often consumed during the Catholic holiday, Lent, even though they are reptiles, not fish. Conservation organizations have written letters to the Pope asking that he declare turtles meat.
Moreover, global warming may also cause a threat to sea turtles. Since temperatures in the sands define the sex of the turtle while developing in the egg, many feared rising temperatures would only produce one sex, but more research remains to be done in order to understand how climate change might affect sea turtle gender distribution.
Sea turtles can also be affected by Fibropapillomatosis, a disease that has been found amongst sea turtle populations and causes tumors.
Injured sea turtles are sometimes able to be rescued and rehabilitated by professional organizations such as the Mote Marine Laboratory in Sarasota, Florida, the Marine Mammal Center in Northern California, and the ClearWater Marine Aquarium in Clearwater Florida. and the Sea Turtle Inc. organization in South Padre Island ,TX. One such turtle, named Nickel for the coin that was found lodged in her throat, lives at the Shedd Aquarium in Chicago.
In the Caribbean, reserchers are having some success in assisting a comeback. On September 2007,Corpus Christi.Texas wildlife officials found a record of 128 Kemp's ridley sea turtle nests on Texas beaches, including 81 on North Padre Island (Padre Island National Seashore) and 4 on Mustang Island.. Wildlife officials released 10,594 Kemp's ridleys hatchlings along the Texas coast this year. The turtles are endangered due to shrimpers' nets and they are popular in Mexico as boot material and food.
In 2007, the U.S. Fish and Wildlife Service and the National Marine Fisheries Service finished a joint study assessing the worldwide populations of all sea turtle species. It was determined that the leatherback, the hawksbill and the Kemp's Ridley populations were endangered while that of green turtles and olive ridleys were threatened.
In Southeast Asia, the Philippines has had several initiatives dealing with the issue of turtle conservation. In 2007, the province of Batangas in the Philippines declared the catching and eating of Pawikans illegal. However, the law seems to have little effect as Pawikan eggs are still in demand in Batangan markets. Today, one can easily purchase three Pawikan eggs for a mere PhP20. On January 23,2008, the Coastal Resource Management Coordinator arrested and detained fisherman Israel Jimenez, 40, from Poblacion,Bacuag, Surigao del Norte who slaughtered an endangered sea turtle, pending the filing of case by the Bureau of Fisheries and Aquatic Resources.
In September 2007, several Chinese poachers were apprehended off the Turtle Islands in the country's southernmost province of Tawi-Tawi. The poachers were discovered to have collected more than a hundred sea turtles, along with 10,000 turtle eggs.
Sea turtles play key roles in two ecosystems that are critical to them as well as to humans—the oceans and beaches/dunes. If sea turtles were to become extinct, the negative impact on beaches and the oceans would potentially be significant.
In the oceans, for example, sea turtles, especially green sea turtles, are one of the very few creatures (manatees are another) that eat a type of vegetation called sea grass that grows on the sea floor. Sea grass must be kept short to remain healthy, and beds of healthy sea grass are essential breeding and development areas for many species of fish and other marine life. A decline or loss of sea grass beds would mean a loss of the marine species that directly depend on the beds, which would trigger a chain reaction and negatively impact marine and human life. When one part of an ecosystem is destroyed, the other parts will follow.
Beaches and dunes are a fragile ecosystem that does not get many nutrients to support its vegetation, which is needed to help prevent erosion. Sea turtles contribute nutrients to dune vegetation from their eggs. Every year, sea turtles lay countless numbers of eggs in beaches during nesting season. Along one twenty-mile (32 km) stretch of beach in Florida alone, for example, more than 150,000 pounds of eggs are laid each year. Nutrients from hatched eggs as well as from eggs that never hatch and from hatchlings that fail to make it into the ocean are all sources of nutrients for dune vegetation. A decline in the number of sea turtles means fewer eggs laid, less nutrients for the sand dunes and its vegetation, and a higher risk for beach erosion.
Sea turtles, along with other turtles and tortoises, are part of the Order Testudines. Seven distinct species of sea turtles grace our oceans today; they constitute a single radiation that was distinct from all other turtles at least 110 million years ago. During that radiation, sea turtles split into two main subgroups, which still exist today: the unique family Dermochelyidae, which consists of a single species, the leatherback; and the six species of hard-shelled sea turtle, in the family Cheloniidae.
After about 30 years of maturing, adult female sea turtles return to the land to nest at night, usually on the same beach from which they hatched. This can take place every two to four years in maturity. They make from four to seven nests per nesting season.
All sea turtles generally employ the same methods when making a nest. A mature nesting female hauls herself onto the beach until she finds suitable sand on which to create a nest. Using her hind flippers, the female proceeds to dig a circular hole 40 to 50 centimeters deep. After the hole is dug, the female then starts filling the nest with a clutch of soft-shelled eggs one by one until she has deposited around 150 to 200 eggs, depending on the turtle's species. The nest is then re-filled with loose sand by the female, re-sculpting and smoothing the sand over the nest until it is relatively undetectable visually. The whole process takes around thirty minutes to a little over an hour. After the nest is laid, the female then returns to the ocean.
Some of the eggs are unfertilized and the rest contain young turtles.Incubation takes about two months. The length of incubation and the gender of the hatchling depends on the temperature of the sand. Darker sands maintain higher temperatures, decreasing incubation time and increasing the frequency of female hatchlings. When the time comes, these hatchlings tear their way out of their shells with their snout and once they have reached the surface of the sand, they will instinctively head towards the sea. Only a very small proportion of them (usually .01%) will be successful, as many predators wait to eat the steady stream of new hatched turtles (since many sea turtles lay eggs en masse, the eggs also hatch en masse).
The hatchlings then proceed into the open ocean, borne on oceanic currents that they often have no control over. While in the open ocean, it used to be the case that what happened to sea turtle young during this stage in their lives was unknown. However in 1987, it was discovered that the young of Chelonia mydas and Caretta caretta spent a great deal of their pelagic lives in floating sargassum beds - thick mats of unanchored seaweed floating in the middle of the ocean. Within these beds, they found ample shelter and food. In the absence of sargassum beds, turtle young feed in the vicinity of upwelling "fronts". In 2007, it was verified that green turtle hatchlings spend the first three to five years of their lives in pelagic waters. Out in the open ocean, pre-juveniles of this particular species were found to feed on zooplankton and smaller nekton before they are recruited into inshore seagrass meadows as obligate herbivores.
Like many other animals in the world, sea turtles have predators. An example of natural protection is their shell. Other protections include the ability of some species' massive jaws to suddenly snap shut, and to stay underwater for hours on end; these are both instinctual and natural. Turtles have many senses to aid them in the sea. Sea turtle ears have a single bone in the middle ear that conducts vibrations to the inner ear. Researchers have found that sea turtles respond to low frequency sounds and vibrations. Sea turtles have an extremely good eyesight in water but are shortsighted on land. Under experimental conditions, the loggerhead and green sea turtle hatchlings showed a preference for ultraviolet, blue-green and violet light. Sea turtles are touch-sensitive on the soft parts of their flippers and on their shell. Most researchers' theories portray that sea turtles have an acute sense of smell in the water. Their experiments showed that the hatchlings reacted to the scent of shrimp. This sense allows sea turtles to locate food in deep and murky water. Sea turtles open their mouths a bit and draw in water through the nose, then immediately empty it out again through the mouth. Pulsating movements of the throat are thought to be associated with smelling. Sea turtles have very hard shells. Sea turtles are many different colors like blue green and light violet. Sea turtles flippers are very soft and sensitive.
Marine turtles are caught worldwide, despite it being illegal to hunt most of the species in many countries. A great deal of intentional marine turtle harvests worldwide are for the food industry. In many parts of the world, the flesh of sea turtles are considered fine dining. Texts dating back to the fifth century B.C. describes sea turtles as exotic delicacies in ancient China. Historically, many coastal communities around the world have depended on sea turtles as a source of protein. Several turtles could be harvested at once and kept alive on their backs for months until needed. The skin of the flippers are also prized for use as shoes and assorted leather-goods.
To a much lesser extent, specific species of marine turtles are targeted not for their flesh, but for their shells. Tortoisehell, a traditional decorative ornamental material used in Japan and China, is derived from the carapace scutes of the hawksbill turtle. The use of marine turtle shells for decorative purposes is by no means limited to the orient. Since ancient times, the shells of sea turtles (primarily the hawksbill) have been used by the ancient Greeks and ancient Romans. Various articles and ornaments used by the elite of these societies, such as combs and brushes, were from processed turtle scutes. The Moche people of ancient Peru worshipped the sea and its animals. They often depicted sea turtles in their art.
All species of sea turtles are listed as threatened or endangered. The leatherback, Kemp's ridley, and hawksbill turtles are listed as critically endangered. The olive ridley and green turtles are considered endangered, and the loggerhead is a threatened species. The flatback's conservation status is unclear due to a lack of research data.
Sea turtles used to be hunted on a large scale in the whaling days for their meat, fat and shells. Coastal peoples have also been known to gather turtle eggs for consumption. One of their most significant threats now comes from bycatch due to various fishing methods,long-line fishing has been blamed as one of the causes of accidental sea turtle deaths, and the black market demand for tortoiseshell for both decoration and supposed health benefits.
Nets used in shrimp trawling and fishing have been known to cause the accidental deaths of sea turtles. The turtles, as air-breathing reptiles, must surface to breathe. Caught in a fisherman's net, they are unable to go to the surface to breathe and suffocate to death in the net. In early 2007, almost a thousand sea turtles were killed inadvertently in the Bay of Bengal over the course of a few months as a result of becoming trapped in fishing nets.
However some relatively inexpensive changes to fishing techniques, such as slightly larger hooks and traps from which sea turtles can escape, can dramatically cut the mortality rate.Turtle Excluder Devices (TEDS) have reduced sea turtle bycatch in shrimp nets by 97 percent. Another danger comes from marine debris, especially from abandoned fishing nets in which they can become entangled.
Beach development is another area which poses threats to sea turtles. Since sea turtles return to the same beach locations to nest, if these areas are developed they may be left with nowhere to nest, or their nesting locations may be threatened by human activity. Therefore, there has been a movement to protect these areas, in some cases by special police. In some areas, such as the east coast of Florida, after the adult turtles lay their eggs, they are dug up and relocated to special fenced nurseries where they can be protected from beach traffic. This is not the best thing to do, as many turtle species return to the beach on which they were born. Hatchlings find their way to the ocean by crawling towards the brightest horizon, but often become disoriented on developed stretches of coastline. Special lighting ordinances may also be enforced to prevent lights from shining on the beach and confusing young hatchlings, causing them to crawl towards the light and away from the water, usually crossing a road. A turtle-safe lighting system uses red light in place of white light as sea turtles can't see red light.
Another major threat to sea turtles is the black market trade in eggs and meat. This is a pervasive problem throughout the world, but especially a concern in the Philippines, India, Indonesia and throughout the coastal nations of Latin America. Estimates are as high as 35,000 turtles killed a year in Mexico and the same number in Nicaragua. Conservationists in Mexico and the United States have launched "Don't Eat Sea Turtle" campaigns in order to reduce the urban black market trade in sea turtle products. These campaigns have involved figures such as Pope John Paul II,Dorismar,Los Tigres del Norte and Mana. Sea turtles are often consumed during the Catholic holiday, Lent, even though they are reptiles, not fish. Conservation organizations have written letters to the Pope asking that he declare turtles meat.
Moreover, global warming may also cause a threat to sea turtles. Since temperatures in the sands define the sex of the turtle while developing in the egg, many feared rising temperatures would only produce one sex, but more research remains to be done in order to understand how climate change might affect sea turtle gender distribution.
Sea turtles can also be affected by Fibropapillomatosis, a disease that has been found amongst sea turtle populations and causes tumors.
Injured sea turtles are sometimes able to be rescued and rehabilitated by professional organizations such as the Mote Marine Laboratory in Sarasota, Florida, the Marine Mammal Center in Northern California, and the ClearWater Marine Aquarium in Clearwater Florida. and the Sea Turtle Inc. organization in South Padre Island ,TX. One such turtle, named Nickel for the coin that was found lodged in her throat, lives at the Shedd Aquarium in Chicago.
In the Caribbean, reserchers are having some success in assisting a comeback. On September 2007,Corpus Christi.Texas wildlife officials found a record of 128 Kemp's ridley sea turtle nests on Texas beaches, including 81 on North Padre Island (Padre Island National Seashore) and 4 on Mustang Island.. Wildlife officials released 10,594 Kemp's ridleys hatchlings along the Texas coast this year. The turtles are endangered due to shrimpers' nets and they are popular in Mexico as boot material and food.
In 2007, the U.S. Fish and Wildlife Service and the National Marine Fisheries Service finished a joint study assessing the worldwide populations of all sea turtle species. It was determined that the leatherback, the hawksbill and the Kemp's Ridley populations were endangered while that of green turtles and olive ridleys were threatened.
In Southeast Asia, the Philippines has had several initiatives dealing with the issue of turtle conservation. In 2007, the province of Batangas in the Philippines declared the catching and eating of Pawikans illegal. However, the law seems to have little effect as Pawikan eggs are still in demand in Batangan markets. Today, one can easily purchase three Pawikan eggs for a mere PhP20. On January 23,2008, the Coastal Resource Management Coordinator arrested and detained fisherman Israel Jimenez, 40, from Poblacion,Bacuag, Surigao del Norte who slaughtered an endangered sea turtle, pending the filing of case by the Bureau of Fisheries and Aquatic Resources.
In September 2007, several Chinese poachers were apprehended off the Turtle Islands in the country's southernmost province of Tawi-Tawi. The poachers were discovered to have collected more than a hundred sea turtles, along with 10,000 turtle eggs.
Sea turtles play key roles in two ecosystems that are critical to them as well as to humans—the oceans and beaches/dunes. If sea turtles were to become extinct, the negative impact on beaches and the oceans would potentially be significant.
In the oceans, for example, sea turtles, especially green sea turtles, are one of the very few creatures (manatees are another) that eat a type of vegetation called sea grass that grows on the sea floor. Sea grass must be kept short to remain healthy, and beds of healthy sea grass are essential breeding and development areas for many species of fish and other marine life. A decline or loss of sea grass beds would mean a loss of the marine species that directly depend on the beds, which would trigger a chain reaction and negatively impact marine and human life. When one part of an ecosystem is destroyed, the other parts will follow.
Beaches and dunes are a fragile ecosystem that does not get many nutrients to support its vegetation, which is needed to help prevent erosion. Sea turtles contribute nutrients to dune vegetation from their eggs. Every year, sea turtles lay countless numbers of eggs in beaches during nesting season. Along one twenty-mile (32 km) stretch of beach in Florida alone, for example, more than 150,000 pounds of eggs are laid each year. Nutrients from hatched eggs as well as from eggs that never hatch and from hatchlings that fail to make it into the ocean are all sources of nutrients for dune vegetation. A decline in the number of sea turtles means fewer eggs laid, less nutrients for the sand dunes and its vegetation, and a higher risk for beach erosion.
Sea turtles, along with other turtles and tortoises, are part of the Order Testudines. Seven distinct species of sea turtles grace our oceans today; they constitute a single radiation that was distinct from all other turtles at least 110 million years ago. During that radiation, sea turtles split into two main subgroups, which still exist today: the unique family Dermochelyidae, which consists of a single species, the leatherback; and the six species of hard-shelled sea turtle, in the family Cheloniidae.
Family Cheloniidae
Chelonia mydas
1 Eretmochelys imbricata
1 Eretmochelys imbricata
2 Natator depressus
3 Caretta caretta
4 Lepidochelys kempii
5 Lepidochelys olivacea
Family Dermochelyidae
Family Dermochelyidae
Dermochelys coriacea
Chelonia mydas, commonly known as the green turtle is a large redish sea turtle belonging to the family Cheloniidae. It is the only species in the genus Chelonia. The range of the species extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic and Pacific Oceans. Their common name derives from the green fat underneath their shell which can vary from 10 pounds to 100 pounds because of how much they eat.
The green turtle is the quintessential sea turtle, possessing a dorsoventrally-flattened body covered by a large, teardrop-shaped carapace and a pair of large, paddle-like flippers. Despite the turtle's common name, it is lightly-colored all around while its carapace's hues range from olive-brown to black in Eastern Pacific green turtles. The turtle is actually named for the greenish coloration of its fat and flesh. Unlike other members of its family such as the hawksbill and loggerhead turtles, Chelonia mydas is mostly herbivorous. The adults are commonly found in shallow lagoons, feeding mostly on various species of seagrass.
Like other sea turtles, green turtles are known to migrate long distances between their feeding grounds and the beaches they hatched from. Many islands worldwide have been called Turtle Islands primarily for the large amounts of green turtles that nest on their beaches each year. Female turtles dredge themselves onto beaches and lay eggs in nests that they dig during the night. After a period of time, hatchlings emerge from the nests and head for the water. Those that survive grow to maturity and live to a maximum of eighty years.
As a species recognized as endangered by the IUCN and CITES, Chelonia mydas is protected from exploitation in most countries worldwide. It is illegal to collect, harm or kill individual turtles. In addition, many countries have implemented various laws and ordinances to protect individual turtles and turtle nesting areas within their jurisdiction. However, the turtles' populations are still in danger because of several human practices. In some countries, the turtles are still hunted for their flesh and their eggs are collected from nests and eaten as a delicacy. Pollution indirectly harms the turtle populations both on the population and the individual scale.
The green turtle is the quintessential sea turtle, possessing a dorsoventrally-flattened body covered by a large, teardrop-shaped carapace and a pair of large, paddle-like flippers. Despite the turtle's common name, it is lightly-colored all around while its carapace's hues range from olive-brown to black in Eastern Pacific green turtles. The turtle is actually named for the greenish coloration of its fat and flesh. Unlike other members of its family such as the hawksbill and loggerhead turtles, Chelonia mydas is mostly herbivorous. The adults are commonly found in shallow lagoons, feeding mostly on various species of seagrass.
Like other sea turtles, green turtles are known to migrate long distances between their feeding grounds and the beaches they hatched from. Many islands worldwide have been called Turtle Islands primarily for the large amounts of green turtles that nest on their beaches each year. Female turtles dredge themselves onto beaches and lay eggs in nests that they dig during the night. After a period of time, hatchlings emerge from the nests and head for the water. Those that survive grow to maturity and live to a maximum of eighty years.
As a species recognized as endangered by the IUCN and CITES, Chelonia mydas is protected from exploitation in most countries worldwide. It is illegal to collect, harm or kill individual turtles. In addition, many countries have implemented various laws and ordinances to protect individual turtles and turtle nesting areas within their jurisdiction. However, the turtles' populations are still in danger because of several human practices. In some countries, the turtles are still hunted for their flesh and their eggs are collected from nests and eaten as a delicacy. Pollution indirectly harms the turtle populations both on the population and the individual scale.
Many turtles die as a result of being caught in fishermen's nets and drowning. Finally, habitat loss due to human development is a major reason for the loss of green turtle nesting beaches.
The appearance of the green turtle is that of a typical sea turtle. 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 are known to grow to 5 feet (1.5 m) long. While individuals have been caught that reached weights of up to 315 kilograms (695 lb), the average weight of mature individuals is around 200 kilograms (440 lb). The largest Chelonia mydas ever recorded weighed 395 kilograms (871 pounds).
Anatomically, there are a few characteristics that distinguish the green turtle from the other members of its family. Unlike the closely-related hawksbill turtle, the green turtle's snout is very short and its beak is unhooked. The horny sheath of the turtle's upper jaw possesses a slightly-denticulated edge while its lower jaw has stronger, serrated, more defined denticulation. The dorsal surface of the turtle's head has a single pair of prefrontal scales. Its carapace is composed of five central scutes flanked by four pairs of lateral scutes. Underneath, the green turtle has four pairs of infra-marginal scutes covering the area between the turtle's plastron and its shell. Mature C. mydas front appendages have only a single claw (as opposed to the hawksbill's two), although a second claw is sometimes prominent in young specimens.
The carapace of the turtle is known to have various color patterns that change over time. Hatchlings of C. mydas, like those of other marine turtles, have mostly black carapaces and light-colored plastrons. Carapaces of juveniles are dark brown to olive, while those of mature adults are either entirely brown, spotted or marbled with variegated rays. Underneath, the turtle's plastron is hued yellow. C. mydas limbs are dark-colored and lined with yellow, and are usually marked with a large dark brown spot in the center of each appendage.
Sea turtles spend almost all their lives submerged but must breathe air for the oxygen needed to meet the demands of vigorous activity. With a single explosive exhalation and rapid inhalation, sea turtles can quickly replace the air in their lungs. The lungs are adapted to permit a rapid exchange of oxygen and to prevent gasses from being trapped during deep dives. The blood of sea turtles can deliver oxygen efficiently to body tissues even at the pressures encountered during diving. During routine activity green and loggerhead turtles dive for about 4 to 5 minutes and surface to breathe for 1 to 3 seconds.Turtles can rest or sleep underwater for several hours at a time but submergence time is much shorter while diving for food or to escape predators. Breath-holding ability is affected by activity and stress, which is why turtles drown in shrimp trawls and other fishing gear within a relatively short time.
The range of Chelonia mydas extends throughout tropical and subtropical oceans worldwide. There are two major subpopulations of C. mydas, the Atlantic and the Eastern Pacific subpopulations. Each population is genetically-distinct, with has its own set of nesting and feeding grounds within the population's known range.
Chelonia mydas can generally be found throughout the entire Atlantic Ocean. Individuals have been spotted as far north as Canada in the Western Atlantic and the British Isles in the east. The subpopulation's southern range is known until past the southern tip of Africa in the east and Argentina in the Western Atlantic. The major nesting sites in the region can be found on various islands in the Caribbean, along the eastern shores of the continental United States, the eastern coast of the South American continent and most notably, on isolated islands in the North Atlantic.
In the Caribbean, major nesting sites have been identified on Aves Island, the U.S. Virgin Islands, Puerto Rico and Costa Rica. One of the most important nesting grounds for the region's green turtle population can be located in Tortuguero in Costa Rica. In fact, a great majority of the Caribbean region's C. mydas population hails from a few beaches in Tortuguero. Within United States waters, minor nesting sites have been noted in the states of Georgia , North and South Carolina and all along the east coast of Florida.Hutchinson Island in particular is a major nesting area in Florida waters. Notable nesting locations in South America include secluded beaches in Surinam and French Guiana. In the Southern Atlantic Ocean, the most notable nesting grounds for Chelonia mydas are found on the island of Ascension. On that particular island, annual nesting occurs in the volume of around 6,000 to 13,000 individual turtle nests.
In contrast with the sporadic distribution of their nesting sites, Chelonia mydas feeding grounds are much more widely distributed throughout the region. Important feeding grounds for the green sea turtle in Florida include Indian River Lagoon, the Florida Keys, Florida Bay, Homosassa, Crystal River and Cedar Key.
In the Pacific, the range of the green turtle reaches as far north as the southern coast of Alaska and as far south as Chile in the east. The turtle's distribution in the Western Pacific is known as far north as Japan and even southern parts of Russia's Pacific coast and as far south as the northern tip of New Zealand and a few islands further south of Tasmania. The turtles can be found throughout the entire range of the Indian Ocean.
Significant nesting grounds are scattered throughout the entire region. Pacific green turtle nesting grounds are found in Mexico, the Hawaiian Islands, the South Pacific, the northern coast of Australia and Southeast Asia. In the Indian Ocean, major nesting colonies have been recorded in India, Pakistan and other coastal countries in the region. A few nesting grounds have been reported along the east coast of the African continent including some islands in the waters around Madagascar.
East Pacific green turtles nesting grounds are well-studied all along the Mexican coast. These turtles have been found to feed in seagrass pastures in the Gulf of California. Green turtles belonging to the distinct Hawaiian subpopulation are known to nest at the protected French Frigate Shoals some 800 kilometers to the west of the Hawaiian Islands. In the Philippines, green turtles are known to nest in the Turtle Islands along with closely-related hawksbill turtles. There are also a few nesting beaches in Indonesia, one of them in the Meru Betiri National Reserve in East Java. The green sea turtles on the Great Barrier Reef have two genetically distinct populations; one in the Northern Great Barrier Reef, and the other in the Southern half of the reef. Within the reef, twenty separate locations consisting of small islands and cays were identified as nesting sites for either population of C. mydas. Of these, the most important green turtle nesting ground was identified to be on Raine Island.
Major nesting sites of green turtle are common on either side of the Arabian Sea, both in Ash Sharqiyah, Oman, and along the coast of Karachi, Pakistan. Some specific beaches along the area, such as Hawke's Bay and Sandspit, are the common nesting grounds for the region's C. mydas and L.olivacea subpopulation. Sandy beaches along Sindh and Balochistan are also known green turtle nest sites. Some 25 kilometers off the Pakistani coast, Astola island is another known nesting beach.
On December 30,2007, fishermen, using a "hulbot-hulbot" or a fishnet accidentally caught an 80-kilogram, 93 centimeters in length and 82 cm wide, green sea turtle off Barangay Bolong, Zamboanga City, Philippines. December is breeding season of the green sea turtles near the Bolong beach.
As one of the oldest sea turtle species studied, much of what is known of sea turtle ecology was gleaned from studies of green turtles. The ecology of Chelonia mydas changes drastically with each succeeding stage of its life history. For instance, newly-emerged hatchlings are carnivorous ,pelagic organisms part of the open ocean mini-nekton. In contrast, immature juveniles and adult turtles are commonly found in seagrass meadows closer inshore as herbivorous grazers.
Green turtles alternate between three habitat type depending on their current life history stage. Nesting beaches are where the turtles return to lay eggs. Mature turtles spend most of their time in coastal, shallow waters with lush seagrass beds. Seagrass meadows within inshore bays, lagoons and shoals are common locations where adult Chelonia mydas can often be found. This particular species is known to be very selective about their feeding and mating sites and entire generations will often alternately migrate between the same feeding and nesting areas.
After hatching, turtles in their first five years are known to spend a majority of their early life stages in convergence zones within the open ocean.These young turtles are rarely seen as they swim in deep, pelagic waters where they spend the first few years of their lives.
As large and well-protected animals, adult green turtles have few enemies and even fewer predators. Only human beings and the larger sharks are known to feed on C. mydas adults. Specifically,tiger sharks (Galeocerdo cuvier) are known predators of adult green turtles in Hawaiian waters. Juvenile turtles and recently-emerged hatchlings have significantly more predators, including crabs, small mammals and shorebirds.
Adult Chelonia mydas are obligately herbivorous. They almost-exclusively feed on various species of seagrasses and seaweed. They have been observed grazing on various species of macroalgae, specifically Caulerpa, Turbinaria, Spyridia,Codium, and Ulva. While mature green turtles are entirely herbivorous, juveniles are known to subsist on a plethora of marine invertebrates. Select preferred prey items include smaller cnidarians and crustaceans. Their digestive intake of plant matter grows larger as they age, until as mature adults they become obligate herbivores. While it has been previously stated that green turtles do not feed while at their respective nesting areas, it has been shown that gravid turtles do in fact feed while in the waters surrounding their nesting grounds.
Unlike most sea turtles, which spend most of their adult lives in the ocean, Pacific green turtles are known to willingly crawl onto secluded beaches during the day to bask in the sun.
Green turtles migrate long distances between their chosen feeding sites and the beaches from where they hatched. Some C. mydas are known to swim distances of greater than 2,600 kilometers (1,400 nmi) to reach their spawning grounds. Mature turtles will often return to the same exact beach from which they hatched. Individual female green turtles usually mate every two to four years. Males on the other hand, are known to make the trip to their breeding areas every year. As with many species that are found across a wide range of latitudes, mating seasons vary between populations. For most Chelonia mydas in the Caribbean, mating season is from June to September. The French Guiana nesting subpopulation nests from March to June. In the tropics, green turtles are known to nest throughout the year, with some subpopulations preferring particular times of the year. In Pakistan,Indian Ocean . mydas nest all year-round but prefer to nest during the months of July to December.
Green turtles reproduce in the typical way that marine turtles do so. Female turtles control mating; males cannot force females to mate. While it does not seem to offer increased survival among the hatchlings, a few green turtle populations are known to undergo polyandry when mating. After mating in the water, the females haul themselves onto the beach above the high tide line. Upon reaching a suitable nesting site, the gravid female then digs a hole with her hind flippers and deposits a number of eggs in the nest. The number of eggs laid per litter depends on the age of the female and differs from species to species, but C. mydas clutches range between 100 to 200 eggs. After laying eggs, the female then covers the nest with sand and returns to the sea.
After around 45 to 75 days, the eggs hatch. As with other marine turtles, C. mydas eggs hatch during the night and the newly-emerged turtles instinctively head directly towards the water's edge. This undoubtedly is the most dangerous time in a turtle's life, as the hatchlings make their way to the water, various predators such as gulls and crabs pick off many turtles. A significant percentage of turtle hatchlings never make it to the ocean. Just like other sea turtles, little is known of the early life history of newly-hatched green turtles. After this trek to the ocean juvenile green turtles spend from three to five years in the opean ocean as carnivores before they settle as immature juveniles into a more herbivorous, shallow-water lifestyle. It is speculated that they take twenty to fifty years to reach mature size. Individuals of the species are known to live up to eighty years in the wild.
One of the most significant mass-nesting sites for this species is located on Ascension Island in the South Atlantic. Each year on the island, thousands of C. mydas create between 6,000 and 15,000 nests. These particular turtles are among the largest green turtles in the world, many more than a meter in length and weighing up to 300 kilograms.
The green turtle is a member of the tribe Chelonini. In a study conducted in 1993, the status of the genus Chelonia with respect to the other marine turtles was clarified. The carnivorous Eretmochelys (hawksbill),Caretta (loggerhead) and Lepidochelys (Ridley) were confirmed in the tribe Carettini. Herbivorous Chelonia were found distinct enough to warrant their status while establishing that Natator (flatback) was further-removed than previously believed.
The species was originally described by Linnaeus in 1758 as Testudo mydas. In 1868, Bocourt described a particular species of sea turtle as Chelonia agassizii (Chelonia agassizi is a commonly-cited misspelling of this taxon). This "species" was referred to as the black sea turtle. However, research determined that the "black sea turtle" was not genetically distinct from C. mydas and thus taxonomically not a separate species. These two separate species were then united in the same species, Chelonia mydas and were given subspecies status. C. mydas mydas referred to the originally described population while C. mydas agassizi referred to the Pacific population. This subdivision was later determined to be invalid and all members of the species were then designated Chelonia mydas. The oft-mentioned name C. agassizi remains an invalid junior synonym of C. mydas.
The species' common name is derived not from any particular green external coloration of the turtle. The green turtle is so-called because of the greenish color of the turtle's fat, which is only found in a layer between their inner organs and their shell. As a species found worldwide, the green turtle is called differently in some languages and dialects. In Hawaii, the native Hawaiian word honu is used to refer to this species.
While in most countries, it is now illegal to hunt Chelonia mydas along with the other members of its family, sea turtles continue to be caught worldwide. Along with other sea turtles, Chelonia mydas are caught both intentionally and unintentionally in select regions of the world. Prior to the implementation of various protection measures, the turtles' skin was tanned and used as leather for handbags, especially in Hawaii. In ancient China, the flesh of sea turtles including and especially C. mydas was considered a culinary delicacy. Particularly for this species, the turtle's calipee, fat and cartilage are sought as ingredients for making turtle soup.
In some countries like India and China it is considered as a sacred animal according to vastu, astrology and feng shui. Putting turtles into aquariums or in one's house is considered to ensure the family's life to be long and it eliminates all negative energies of the house.
In Indonesia, sea turtle eggs are a popular delicacy in Java. However, the turtle's flesh is regarded as haram or "unclean" under Islamic law (Islam is the primary religion in the region). In Bali, the demand for turtle meat to satisfy traditional consumption at ceremonial and religious feasts has encouraged the harvesting of turtles in the furthest and remotest parts of the Indonesian archipelago. Bali has been importing sea turtles since the 1950s as its own turtle supplies were said to be severely depleted. The ethnic Balinese do not eat the eggs, which are instead sold to local Muslims. The former traditional uses of turtle on Bali were once deemed sustainable, but have been questioned considering a vastly larger human population and thus greater demand. The harvest was until recently described to be the most intensive in the world.
Before the inclusion of the turtles in the Endangered Species Act and the Convention on International Trade in Endangered Species, commercial farms such as the Cayman Turtle Farm in the West Indies bred the turtles for commercial sale. The farms held as many as 100,000 turtles at any one time. When the markets were closed due to protection measures, some farms went bankrupt and most drastically reduced their stock. The farms have since been converted into tourist attractions with around 11,000 turtles at any one time.
There are various threats to the species' survival. Direct and directed threats to individual turtles include hunting of turtles for their flesh and shells and the harvesting of their eggs. More prevalent indirect threats include casualties due to turtles being injured by boat propellers, being caught as bycatch by fishermen's nets without TEDs, pollution and habitat destruction. Pollution effects would include direct-impact disturbances such as effluent from harbors near nesting sites. Habitat loss usually occurs due to human development of their nesting areas. Urban development of beaches, reclamation and an increased level of tourism are examples of such development. An infectious tumor-causing disease known as fibropapillomatosis is also a problem in some green turtle populations. The disease kills a sizeable fraction of the turtles that it infects, though some turtles seem to be resistant to the disease.
Because of these, the many populations of Chelonia mydas worldwide are in various states of vulnerability. The Mediterranean green turtle population is particularly listed as critically endangered. In the East Pacific, green turtle subpopulations in Hawaii and Southern California have been designated threatened. Specific Mexican subpopulations are listed as endangered. In the Caribbean, the Florida nesting population is also listed as endangered. In the Indian Ocean, the World Wide Fund for Nature has labeled nesting populations in Pakistan as "rare and declining."
Since 2004, Chelonia mydas has been classified by the IUCN Red List of Threatened Species as endangered. It is listed as classified under the EN A2bd criteria, which essentially states that the species' wild populations are facing a high risk of extinction because of several factors. These factors include a probably reduction of more than 50% in the size of the worldwide C. mydas population over the past decade. This was determined by using abundance indices and by projecting a potential level of exploitation of the species' numbers.
The species has been officially classified as an endangered species since 1982, when the International Union for the Conservation of Nature listed Chelonia mydas as endangered. Throughout various reassessments and subsequent publications, the conservation status of the turtle has not changed over time. The 1986,1988, 1990 and 1994 editions of the IUCN Red List retained the species' endangered status. In the landmark 1996 edition of the Red List, C. mydas remained listed as an endangered species. In 2001, a petition was filed to delist the species as an endangered species. At the time, the species was listed as endangered under the strict EN A1abd criteria. The petitioner claimed that at the time, there was ample evidence to suggest that some green turtle populations were large, stable and in some cases, increasing. The IUCN Standards and Petitions Subcommittee determined in a ruling that visual counts of nesting females could not be considered as "direct observation" and thus downgraded the species' status as EN A1bd - retaining the turtle's endangered status.
As a member of the family Cheloniidae, Chelonia mydas is listed on Appendix I of the Convention on International Trade in Endangered Species as of May 3,2007. The species was originally listed on Appendix II in 1975. The entire family was put onto Appendix I in 1977, with the exception of the Australian population of C. mydas. In 1981, all populations of the species were brought into Appendix I, including the Australian population. As covered by Appendix I of CITES, it is illegal to import or export, kill, capture or harass green turtles.
In addition to management by global entities such as the IUCN and CITES, specific countries around the world whose jurisdiction turtle nesting and feeding grounds fall under have taken specific conservation efforts in order to protect the species.
Eco-tourism has been one specific thrust in Sabah,Borneo. The island of Pulau Selingan is home to a turtle hatchery. Staff on the island collect some of the eggs laid each night and place them in a hatchery to protect them from predators. Incubation of the eggs apparently takes around sixty days. Once hatched, tourists are permitted to assist in the release of the baby turtles into the sea. In the United States, the U.S. Fish and Wildlife Services classified Chelonia mydas as a threatened species, rendering it a federal offense to capture or otherwise kill an individual turtle. In part due to this, the Hawaiian green turtle subpopulation has made a remarkable comeback and is now also the subject of eco-tourism and has become something of a state mascot. Students of Hawaii Prepatory Academy on the Big Island have tagged thousands of specimens since the early 1990s. In the United Kingdom the species is protected by a Biodiversity Action Plan, due to harvesting in excess from human overpopulation and marine pollution. The Pakistani-branch of the World Wide Fund for Nature has been initiating various projects for secure turtle hatching since the 1980s. However, the population has continued to decline due to various factors.
In the Atlantic, conservation initiatives have centered around nesting sites in the Caribbean. The Tortuguero nesting beaches in Costa Rica have been the subject of egg-collection limits since the 1950s. Two decades after, the Tortugero National Park formally established in 1976 ensuring the protection of that region's nesting grounds. On Ascension Island where some of the species' most important nesting beaches are, an active conservation program has been implemented.Karumbe has been monitoring foraging and developmental areas of juvenile green turtles (Chelonia mydas)in Uruguay from 1999.
The appearance of the green turtle is that of a typical sea turtle. 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 are known to grow to 5 feet (1.5 m) long. While individuals have been caught that reached weights of up to 315 kilograms (695 lb), the average weight of mature individuals is around 200 kilograms (440 lb). The largest Chelonia mydas ever recorded weighed 395 kilograms (871 pounds).
Anatomically, there are a few characteristics that distinguish the green turtle from the other members of its family. Unlike the closely-related hawksbill turtle, the green turtle's snout is very short and its beak is unhooked. The horny sheath of the turtle's upper jaw possesses a slightly-denticulated edge while its lower jaw has stronger, serrated, more defined denticulation. The dorsal surface of the turtle's head has a single pair of prefrontal scales. Its carapace is composed of five central scutes flanked by four pairs of lateral scutes. Underneath, the green turtle has four pairs of infra-marginal scutes covering the area between the turtle's plastron and its shell. Mature C. mydas front appendages have only a single claw (as opposed to the hawksbill's two), although a second claw is sometimes prominent in young specimens.
The carapace of the turtle is known to have various color patterns that change over time. Hatchlings of C. mydas, like those of other marine turtles, have mostly black carapaces and light-colored plastrons. Carapaces of juveniles are dark brown to olive, while those of mature adults are either entirely brown, spotted or marbled with variegated rays. Underneath, the turtle's plastron is hued yellow. C. mydas limbs are dark-colored and lined with yellow, and are usually marked with a large dark brown spot in the center of each appendage.
Sea turtles spend almost all their lives submerged but must breathe air for the oxygen needed to meet the demands of vigorous activity. With a single explosive exhalation and rapid inhalation, sea turtles can quickly replace the air in their lungs. The lungs are adapted to permit a rapid exchange of oxygen and to prevent gasses from being trapped during deep dives. The blood of sea turtles can deliver oxygen efficiently to body tissues even at the pressures encountered during diving. During routine activity green and loggerhead turtles dive for about 4 to 5 minutes and surface to breathe for 1 to 3 seconds.Turtles can rest or sleep underwater for several hours at a time but submergence time is much shorter while diving for food or to escape predators. Breath-holding ability is affected by activity and stress, which is why turtles drown in shrimp trawls and other fishing gear within a relatively short time.
The range of Chelonia mydas extends throughout tropical and subtropical oceans worldwide. There are two major subpopulations of C. mydas, the Atlantic and the Eastern Pacific subpopulations. Each population is genetically-distinct, with has its own set of nesting and feeding grounds within the population's known range.
Chelonia mydas can generally be found throughout the entire Atlantic Ocean. Individuals have been spotted as far north as Canada in the Western Atlantic and the British Isles in the east. The subpopulation's southern range is known until past the southern tip of Africa in the east and Argentina in the Western Atlantic. The major nesting sites in the region can be found on various islands in the Caribbean, along the eastern shores of the continental United States, the eastern coast of the South American continent and most notably, on isolated islands in the North Atlantic.
In the Caribbean, major nesting sites have been identified on Aves Island, the U.S. Virgin Islands, Puerto Rico and Costa Rica. One of the most important nesting grounds for the region's green turtle population can be located in Tortuguero in Costa Rica. In fact, a great majority of the Caribbean region's C. mydas population hails from a few beaches in Tortuguero. Within United States waters, minor nesting sites have been noted in the states of Georgia , North and South Carolina and all along the east coast of Florida.Hutchinson Island in particular is a major nesting area in Florida waters. Notable nesting locations in South America include secluded beaches in Surinam and French Guiana. In the Southern Atlantic Ocean, the most notable nesting grounds for Chelonia mydas are found on the island of Ascension. On that particular island, annual nesting occurs in the volume of around 6,000 to 13,000 individual turtle nests.
In contrast with the sporadic distribution of their nesting sites, Chelonia mydas feeding grounds are much more widely distributed throughout the region. Important feeding grounds for the green sea turtle in Florida include Indian River Lagoon, the Florida Keys, Florida Bay, Homosassa, Crystal River and Cedar Key.
In the Pacific, the range of the green turtle reaches as far north as the southern coast of Alaska and as far south as Chile in the east. The turtle's distribution in the Western Pacific is known as far north as Japan and even southern parts of Russia's Pacific coast and as far south as the northern tip of New Zealand and a few islands further south of Tasmania. The turtles can be found throughout the entire range of the Indian Ocean.
Significant nesting grounds are scattered throughout the entire region. Pacific green turtle nesting grounds are found in Mexico, the Hawaiian Islands, the South Pacific, the northern coast of Australia and Southeast Asia. In the Indian Ocean, major nesting colonies have been recorded in India, Pakistan and other coastal countries in the region. A few nesting grounds have been reported along the east coast of the African continent including some islands in the waters around Madagascar.
East Pacific green turtles nesting grounds are well-studied all along the Mexican coast. These turtles have been found to feed in seagrass pastures in the Gulf of California. Green turtles belonging to the distinct Hawaiian subpopulation are known to nest at the protected French Frigate Shoals some 800 kilometers to the west of the Hawaiian Islands. In the Philippines, green turtles are known to nest in the Turtle Islands along with closely-related hawksbill turtles. There are also a few nesting beaches in Indonesia, one of them in the Meru Betiri National Reserve in East Java. The green sea turtles on the Great Barrier Reef have two genetically distinct populations; one in the Northern Great Barrier Reef, and the other in the Southern half of the reef. Within the reef, twenty separate locations consisting of small islands and cays were identified as nesting sites for either population of C. mydas. Of these, the most important green turtle nesting ground was identified to be on Raine Island.
Major nesting sites of green turtle are common on either side of the Arabian Sea, both in Ash Sharqiyah, Oman, and along the coast of Karachi, Pakistan. Some specific beaches along the area, such as Hawke's Bay and Sandspit, are the common nesting grounds for the region's C. mydas and L.olivacea subpopulation. Sandy beaches along Sindh and Balochistan are also known green turtle nest sites. Some 25 kilometers off the Pakistani coast, Astola island is another known nesting beach.
On December 30,2007, fishermen, using a "hulbot-hulbot" or a fishnet accidentally caught an 80-kilogram, 93 centimeters in length and 82 cm wide, green sea turtle off Barangay Bolong, Zamboanga City, Philippines. December is breeding season of the green sea turtles near the Bolong beach.
As one of the oldest sea turtle species studied, much of what is known of sea turtle ecology was gleaned from studies of green turtles. The ecology of Chelonia mydas changes drastically with each succeeding stage of its life history. For instance, newly-emerged hatchlings are carnivorous ,pelagic organisms part of the open ocean mini-nekton. In contrast, immature juveniles and adult turtles are commonly found in seagrass meadows closer inshore as herbivorous grazers.
Green turtles alternate between three habitat type depending on their current life history stage. Nesting beaches are where the turtles return to lay eggs. Mature turtles spend most of their time in coastal, shallow waters with lush seagrass beds. Seagrass meadows within inshore bays, lagoons and shoals are common locations where adult Chelonia mydas can often be found. This particular species is known to be very selective about their feeding and mating sites and entire generations will often alternately migrate between the same feeding and nesting areas.
After hatching, turtles in their first five years are known to spend a majority of their early life stages in convergence zones within the open ocean.These young turtles are rarely seen as they swim in deep, pelagic waters where they spend the first few years of their lives.
As large and well-protected animals, adult green turtles have few enemies and even fewer predators. Only human beings and the larger sharks are known to feed on C. mydas adults. Specifically,tiger sharks (Galeocerdo cuvier) are known predators of adult green turtles in Hawaiian waters. Juvenile turtles and recently-emerged hatchlings have significantly more predators, including crabs, small mammals and shorebirds.
Adult Chelonia mydas are obligately herbivorous. They almost-exclusively feed on various species of seagrasses and seaweed. They have been observed grazing on various species of macroalgae, specifically Caulerpa, Turbinaria, Spyridia,Codium, and Ulva. While mature green turtles are entirely herbivorous, juveniles are known to subsist on a plethora of marine invertebrates. Select preferred prey items include smaller cnidarians and crustaceans. Their digestive intake of plant matter grows larger as they age, until as mature adults they become obligate herbivores. While it has been previously stated that green turtles do not feed while at their respective nesting areas, it has been shown that gravid turtles do in fact feed while in the waters surrounding their nesting grounds.
Unlike most sea turtles, which spend most of their adult lives in the ocean, Pacific green turtles are known to willingly crawl onto secluded beaches during the day to bask in the sun.
Green turtles migrate long distances between their chosen feeding sites and the beaches from where they hatched. Some C. mydas are known to swim distances of greater than 2,600 kilometers (1,400 nmi) to reach their spawning grounds. Mature turtles will often return to the same exact beach from which they hatched. Individual female green turtles usually mate every two to four years. Males on the other hand, are known to make the trip to their breeding areas every year. As with many species that are found across a wide range of latitudes, mating seasons vary between populations. For most Chelonia mydas in the Caribbean, mating season is from June to September. The French Guiana nesting subpopulation nests from March to June. In the tropics, green turtles are known to nest throughout the year, with some subpopulations preferring particular times of the year. In Pakistan,Indian Ocean . mydas nest all year-round but prefer to nest during the months of July to December.
Green turtles reproduce in the typical way that marine turtles do so. Female turtles control mating; males cannot force females to mate. While it does not seem to offer increased survival among the hatchlings, a few green turtle populations are known to undergo polyandry when mating. After mating in the water, the females haul themselves onto the beach above the high tide line. Upon reaching a suitable nesting site, the gravid female then digs a hole with her hind flippers and deposits a number of eggs in the nest. The number of eggs laid per litter depends on the age of the female and differs from species to species, but C. mydas clutches range between 100 to 200 eggs. After laying eggs, the female then covers the nest with sand and returns to the sea.
After around 45 to 75 days, the eggs hatch. As with other marine turtles, C. mydas eggs hatch during the night and the newly-emerged turtles instinctively head directly towards the water's edge. This undoubtedly is the most dangerous time in a turtle's life, as the hatchlings make their way to the water, various predators such as gulls and crabs pick off many turtles. A significant percentage of turtle hatchlings never make it to the ocean. Just like other sea turtles, little is known of the early life history of newly-hatched green turtles. After this trek to the ocean juvenile green turtles spend from three to five years in the opean ocean as carnivores before they settle as immature juveniles into a more herbivorous, shallow-water lifestyle. It is speculated that they take twenty to fifty years to reach mature size. Individuals of the species are known to live up to eighty years in the wild.
One of the most significant mass-nesting sites for this species is located on Ascension Island in the South Atlantic. Each year on the island, thousands of C. mydas create between 6,000 and 15,000 nests. These particular turtles are among the largest green turtles in the world, many more than a meter in length and weighing up to 300 kilograms.
The green turtle is a member of the tribe Chelonini. In a study conducted in 1993, the status of the genus Chelonia with respect to the other marine turtles was clarified. The carnivorous Eretmochelys (hawksbill),Caretta (loggerhead) and Lepidochelys (Ridley) were confirmed in the tribe Carettini. Herbivorous Chelonia were found distinct enough to warrant their status while establishing that Natator (flatback) was further-removed than previously believed.
The species was originally described by Linnaeus in 1758 as Testudo mydas. In 1868, Bocourt described a particular species of sea turtle as Chelonia agassizii (Chelonia agassizi is a commonly-cited misspelling of this taxon). This "species" was referred to as the black sea turtle. However, research determined that the "black sea turtle" was not genetically distinct from C. mydas and thus taxonomically not a separate species. These two separate species were then united in the same species, Chelonia mydas and were given subspecies status. C. mydas mydas referred to the originally described population while C. mydas agassizi referred to the Pacific population. This subdivision was later determined to be invalid and all members of the species were then designated Chelonia mydas. The oft-mentioned name C. agassizi remains an invalid junior synonym of C. mydas.
The species' common name is derived not from any particular green external coloration of the turtle. The green turtle is so-called because of the greenish color of the turtle's fat, which is only found in a layer between their inner organs and their shell. As a species found worldwide, the green turtle is called differently in some languages and dialects. In Hawaii, the native Hawaiian word honu is used to refer to this species.
While in most countries, it is now illegal to hunt Chelonia mydas along with the other members of its family, sea turtles continue to be caught worldwide. Along with other sea turtles, Chelonia mydas are caught both intentionally and unintentionally in select regions of the world. Prior to the implementation of various protection measures, the turtles' skin was tanned and used as leather for handbags, especially in Hawaii. In ancient China, the flesh of sea turtles including and especially C. mydas was considered a culinary delicacy. Particularly for this species, the turtle's calipee, fat and cartilage are sought as ingredients for making turtle soup.
In some countries like India and China it is considered as a sacred animal according to vastu, astrology and feng shui. Putting turtles into aquariums or in one's house is considered to ensure the family's life to be long and it eliminates all negative energies of the house.
In Indonesia, sea turtle eggs are a popular delicacy in Java. However, the turtle's flesh is regarded as haram or "unclean" under Islamic law (Islam is the primary religion in the region). In Bali, the demand for turtle meat to satisfy traditional consumption at ceremonial and religious feasts has encouraged the harvesting of turtles in the furthest and remotest parts of the Indonesian archipelago. Bali has been importing sea turtles since the 1950s as its own turtle supplies were said to be severely depleted. The ethnic Balinese do not eat the eggs, which are instead sold to local Muslims. The former traditional uses of turtle on Bali were once deemed sustainable, but have been questioned considering a vastly larger human population and thus greater demand. The harvest was until recently described to be the most intensive in the world.
Before the inclusion of the turtles in the Endangered Species Act and the Convention on International Trade in Endangered Species, commercial farms such as the Cayman Turtle Farm in the West Indies bred the turtles for commercial sale. The farms held as many as 100,000 turtles at any one time. When the markets were closed due to protection measures, some farms went bankrupt and most drastically reduced their stock. The farms have since been converted into tourist attractions with around 11,000 turtles at any one time.
There are various threats to the species' survival. Direct and directed threats to individual turtles include hunting of turtles for their flesh and shells and the harvesting of their eggs. More prevalent indirect threats include casualties due to turtles being injured by boat propellers, being caught as bycatch by fishermen's nets without TEDs, pollution and habitat destruction. Pollution effects would include direct-impact disturbances such as effluent from harbors near nesting sites. Habitat loss usually occurs due to human development of their nesting areas. Urban development of beaches, reclamation and an increased level of tourism are examples of such development. An infectious tumor-causing disease known as fibropapillomatosis is also a problem in some green turtle populations. The disease kills a sizeable fraction of the turtles that it infects, though some turtles seem to be resistant to the disease.
Because of these, the many populations of Chelonia mydas worldwide are in various states of vulnerability. The Mediterranean green turtle population is particularly listed as critically endangered. In the East Pacific, green turtle subpopulations in Hawaii and Southern California have been designated threatened. Specific Mexican subpopulations are listed as endangered. In the Caribbean, the Florida nesting population is also listed as endangered. In the Indian Ocean, the World Wide Fund for Nature has labeled nesting populations in Pakistan as "rare and declining."
Since 2004, Chelonia mydas has been classified by the IUCN Red List of Threatened Species as endangered. It is listed as classified under the EN A2bd criteria, which essentially states that the species' wild populations are facing a high risk of extinction because of several factors. These factors include a probably reduction of more than 50% in the size of the worldwide C. mydas population over the past decade. This was determined by using abundance indices and by projecting a potential level of exploitation of the species' numbers.
The species has been officially classified as an endangered species since 1982, when the International Union for the Conservation of Nature listed Chelonia mydas as endangered. Throughout various reassessments and subsequent publications, the conservation status of the turtle has not changed over time. The 1986,1988, 1990 and 1994 editions of the IUCN Red List retained the species' endangered status. In the landmark 1996 edition of the Red List, C. mydas remained listed as an endangered species. In 2001, a petition was filed to delist the species as an endangered species. At the time, the species was listed as endangered under the strict EN A1abd criteria. The petitioner claimed that at the time, there was ample evidence to suggest that some green turtle populations were large, stable and in some cases, increasing. The IUCN Standards and Petitions Subcommittee determined in a ruling that visual counts of nesting females could not be considered as "direct observation" and thus downgraded the species' status as EN A1bd - retaining the turtle's endangered status.
As a member of the family Cheloniidae, Chelonia mydas is listed on Appendix I of the Convention on International Trade in Endangered Species as of May 3,2007. The species was originally listed on Appendix II in 1975. The entire family was put onto Appendix I in 1977, with the exception of the Australian population of C. mydas. In 1981, all populations of the species were brought into Appendix I, including the Australian population. As covered by Appendix I of CITES, it is illegal to import or export, kill, capture or harass green turtles.
In addition to management by global entities such as the IUCN and CITES, specific countries around the world whose jurisdiction turtle nesting and feeding grounds fall under have taken specific conservation efforts in order to protect the species.
Eco-tourism has been one specific thrust in Sabah,Borneo. The island of Pulau Selingan is home to a turtle hatchery. Staff on the island collect some of the eggs laid each night and place them in a hatchery to protect them from predators. Incubation of the eggs apparently takes around sixty days. Once hatched, tourists are permitted to assist in the release of the baby turtles into the sea. In the United States, the U.S. Fish and Wildlife Services classified Chelonia mydas as a threatened species, rendering it a federal offense to capture or otherwise kill an individual turtle. In part due to this, the Hawaiian green turtle subpopulation has made a remarkable comeback and is now also the subject of eco-tourism and has become something of a state mascot. Students of Hawaii Prepatory Academy on the Big Island have tagged thousands of specimens since the early 1990s. In the United Kingdom the species is protected by a Biodiversity Action Plan, due to harvesting in excess from human overpopulation and marine pollution. The Pakistani-branch of the World Wide Fund for Nature has been initiating various projects for secure turtle hatching since the 1980s. However, the population has continued to decline due to various factors.
In the Atlantic, conservation initiatives have centered around nesting sites in the Caribbean. The Tortuguero nesting beaches in Costa Rica have been the subject of egg-collection limits since the 1950s. Two decades after, the Tortugero National Park formally established in 1976 ensuring the protection of that region's nesting grounds. On Ascension Island where some of the species' most important nesting beaches are, an active conservation program has been implemented.Karumbe has been monitoring foraging and developmental areas of juvenile green turtles (Chelonia mydas)in Uruguay from 1999.
The hawksbill turtle (Eretmochelys imbricata) is a critically endangered sea turtle belonging to the family Cheloniidae. It is the only species in its genus. The species has a worldwide distribution, with Atlantic and Pacific subspecies. Eretmochelys imbricata imbricata is the Atlantic subspecies, while Eretmochelys imbricata bissa is found in the Indo-Pacific region.
The hawksbill's appearance is similar to that of other marine turtles. It has a generally flattened body shape, a protective carapace, and its flipper-like arms are adapted for swimming in the open ocean. E. 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. While the turtle lives a part of its life in the open ocean, it is most often encountered in shallow lagoons and coral reefs where it feeds on its chosen prey, sea sponges. Some of the sponges eaten by E. imbricata are known to be highly toxic and lethal when eaten by other organisms. In addition, the sponges that hawksbills eat are usually those with high silica content, making the turtles one of few animals capable of eating siliceous organisms. They also feed on other invertebrates, such as comb jellies and jellyfish.
Because of human fishing practices, Eretmochelys imbricata populations around the world are threatened with extinction and the turtle has been classified as critically endangered by the World Conservation Union. Several countries, such as China and japan, have valued hunting hawksbill turtles for their flesh, which is considered good eating. Hawksbill turtle shells are the primary source of tortoise shell material, used for decorative purposes. By the Convention on International Trade in Endangered Species, it is illegal to capture and to trade in hawksbill turtles and products derived from them in many nations.
Eretmochelys imbricata has the typical appearance of a marine turtle. Like the other members of its family, it has a depressed body form and flipper-like limbs adapted for swimming. Adult hawksbill turtles have been known to grow up to a metre (3.3 feet) in length, weighing around 80 kilograms (176 lbs) 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 colors radiating to the sides.
The hawksbill turtle has several characteristics that distinguish it from other, closely-related species. Its elongated, tapered head ends in a beak-like mouth (from which its common name is derived), its beak more sharply pronounced and hooked than other sea turtles. The hawksbill's arms have two visible claws on each flipper.
One of the hawksbill's more-easily distinguished characteristics is the pattern of the thick scutes that make up its carapace. While its carapace has five central scutes and four pairs of lateral scutes like several members of the same family, E. imbricata's posterior scutes overlap in such a way as to give the rear margin of its carapace a serrated look, similar to the edge of a saw or a steak knife. The turtle's carapace itself has been known to reach almost a meter in length.
The sand tracks of hawksbill turtles are asymmetrical, as they crawl on land with an alternating gait. This is opposed to the green sea turtle and the leatherback turtle, which crawl rather symmetrically.
Due to its consumption of venomous cnidarians hawksbill turtle flesh can reach certain levels of toxicity. Hawksbill turtles have a wide range, found predominantly in tropical reefs of the Indian,Pacific and Atlantic oceans. Of all the sea turtle species, E. imbricata is the one most associated with tropical waters. Two major subpopulations are acknowledged to exist, the Atlantic and Indo-Pacific subpopulations.
In the Atlantic, E. imbricata populations can be seen as far west as the Gulf of Mexico and the species' eastern range reaches up to the southern tip of the African continent. The northern limits of the species' range can go as far north as Long Island Sound along the northern border of the United States. On the other side of the Atlantic, hawksbills have been sighted in the frigid waters of the English Channel, the species' northernmost occurrence to date. Their southern reach is known all the way to the Cape of Good Hope in Africa.
In the Caribbean, they are known from the Brazilian coast (specifically Bahia), southern Florida and Hawaii. They have also been seen on the beaches of Antigua and Barbuda. Costa Rica has its share of E. imbricata nesting sites, specifically in the vicinity of tortuguero. The island of Cuba is a known feeding ground for the Caribbean hawksbill turtle population. In Puerto Rico, the waters around Mona Island serve as feeding grounds for Caribbean E. imbricata. While a tropical species, E. imbricata has been found in areas in the United States within higher latitudes, such as Massachusetts and Long Island Sound. They have also been seen in the waters off Virginia.
The species' Indo-Pacific population is widespread throughout the entire region. In the Indian Ocean, hawksbills are a common sight all along the east coast of the African continent, including the seas surrounding Madagascar and nearby island groups. The species' Indian Ocean range stretches all the way along the coast of Asia, including the Persian Gulf and the Red Sea, along the entire coast of the Indian subcontinent, across the entire Indonesian archipelago and the northwestern coast of Australia. The Pacific range of E. imbricata is somewhat limited to the ocean's tropical and subtropical regions. Its northernmost reach in the region are the waters off the southwestern tip of the Korean peninsula and the Japanese archipelago. The range continues, enveloping the entire region of Southeast Asia, the entire northern coast of Australia all the way south to the northern part of New Zealand. Across the Pacific, hawksbills are known as far north as the Baja peninsula in Mexico, along the waters off the Central American and South American coast to the northern tip of Chile.
In the Phillipines, there are several known nesting sites for the species. Hawksbill turtle hatchlings have been found on the island of Boracay. A small group of islands in the southwest of the archipelago have been named the "Turtle Islands" precisely because they are known nesting grounds for two species of sea turtle, including Eretmochelys imbricata. (The other being the green sea turtle, Chelonia mydas) In Australia, E. imbricata are known to nest on Milman Island,in the Great Barrier Reef. In the Indian Ocean, hawksbill turtles have been found to nest as far west as Cousine Island in the Seychelles, where the species has been legally protected since 1994. The Seychelles' inner islands and islets, such as Aldabra Island, are ripe feeding grounds for immature hawksbills
Adult hawksbill turtles are primarily found in tropical coral reefs. They are usually seen resting in caves and ledges in and around these reefs, throughout the day. As a highly migratory species, they have also been encountered in a wide range of habitats, from the open ocean to lagoons and even mangrove swamps in estuaries. While much is not known about the habitat preferences of early-life stage E. imbricata, like other sea turtles' young, they are assumed to be completely pelagic and thus make the open sea their home until they mature.
While they are known to be omnivorous, the principal food of hawkbill turtles are sponges. Sponges constitute 70 – 95% of the diets of E. imbricata populations in the Caribbean. However like many spongivores, E. imbricata feed only on a few select species, and will ignore many others. The Caribbean hawksbill populations were found to feed primarily on sponges from the class Demospongiae, specifically ones belonging to the orders Astrophorida,Spirophorida and Hadromerida. Select sponge species known to be fed on by these turtles include Geodia gibberosa. Aside from sponges, hawksbills also feed on algae and cnidarians like jellyfish and sea anemones. The hawksbill is also known to feed on the dangerous jellyfish-like hydrozoan, the Portuguese Man o' War ( Physalia physalis). Hawksbills close their unprotected eyes when they feed on these cnidarians, for Man o' War's stinging cells cannot penetrate the turtles' armoured heads.
Eretmochelys imbricata have shown themselves to be highly resilient and resistant to their prey. Some of the sponges known to be eaten by hawksbills, such as Aaptos aaptos,chondrilla nucula,Tethya actinia,Spheciospongia vesparium and Suberites domuncula, are highly (often lethally) toxic to other organisms. In addition, hawksbills are known to choose sponge species that have a significant amount of silceous spicules, such as Ancorina ,Geodia ,Ecionemia and Placospongia.
Much is not known about the life history of Eretmochelys imbricata. Hawksbills are known to mate biyearly in secluded lagoons in remote islands throughout their range. Mating season for Atlantic hawksbills usually takes place from April to November. For Indian Ocean populations such as the Seychelles hawksbill population, the mating season is from September to February. As with other sea turtles, hawksbills mate in shallow lagoons off the shores of their prospective nesting beaches. After mating, the females drag their heavy bodies high onto the beach during the night. They will then clear out an area and dig a nesting hole using their rear flippers. The female then lays a clutch of eggs in the nest and then covers them with sand. Caribbean and florida nests of E. imbricata normally contain around 140 eggs. After the several-hour-long process, the female then returns to the sea. This is the only time when hawksbill turtles are known to leave the ocean.
The baby turtles, usually weighing less than two dozen grams, hatch during the night after around two months. These newly-emergent hatchlings are darkly-colored, with heart-shaped carapaces measuring around 2.5 centimetres (1 in) long. They instinctually head for the sea, attracted by the reflection of the moon on the water (a mechanism which can be disrupted by anthropogenic light sources such as street lamps and lights). While they emerge under the cover of darkness, baby turtles that do not reach the water by daybreak are preyed upon by predators such as shorebirds and shore crabs.
The early life history of juvenile hawksbill turtles is unknown. Upon reaching the sea, the hatchlings are assumed to enter a pelagic life stage (like other marine turtles) for an undetermined amount of time. While hawksbill turtle growth rates are not known, when E. imbricata juveniles reach around 35 cm, they switch from a pelagic life style to a coral reef-associated one. Hawksbill turtles are hypothesized to reach maturity after thirty years.
While there is no clear consensus because of a lack of data, hawksbill turtles are believed to live from thirty to fifty years in the wild.Like other sea turtles, hawksbill turtles are solitary for most of their lives, venturing far out into crimeajewel seas they only group together to mate. They were once thought to be habitual, but they are now known to be highly migratory. Because of their tough carapaces, hawksbill turtles have no major predators as there are few creatures that are capable of biting through their protective shell.Sharks and esturine crocodiles are a few of their natural predators. Octopuses and some species of pelagic fish have also been known to prey on the adult turtles.
Within the sea turtles, Eretmochelys imbricata has several unique anatomical and ecological traits, including being the only primarily spongivorous reptile known. Because of this, its evolutionary position has been somewhat unclear. Molecular analyses supports the probability that the Eretmochelydae evolved from carnivorous ancestors rather than herbivorous ones. As the taxonomic tribe Carettini is composed of carnivorous species (such as the loggerhead turtle), the hawksbill most probably evolved from them instead of the herbivorous Chelonini, which includes the green turtle.
The hawksbill turtle was originally described by Carolus Linnaeus as Testudo imbricata in 1766. It was moved into the genus Eretmochelys by the Austrian zoologist Leopold Fitzinger in 1843. In 1857, the species was redescribed as Eretmochelys imbricata squamata, a designation that is now invalid.
There are two accepted subspecies in the E. imbricata taxon. Eretmochelys imbricata bissa (Ruppell, 1835) refers to all known populations of the Eretmochelys imbricata that reside in the Pacific Ocean. The Atlantic population has been found to be a separate subspecies, Eretmochelys imbricata imbricata (Linnaeus, 1766). The subspecies name of imbricata was retained because the type specimen that Linnaeus used to initially describe the species was from the Atlantic.
Fitzinger derived the genus' name, Eretmochelys from the Greek roots eretmo and chelys, corresponding to "oar" and "turtle" respectively. The name refers to the turtles' oar-like front flippers. The species' name imbricata is Latin, corresponding to the English term imbricate. This appropriately describes the turtles' overlapping posterior scutes. The Pacific hawksbill's subspecies name, bissa is Latin for "double". The subspecies was originally described as Caretta bissa and the term referred to the then-species' being the second species in the genus.Caretta is the genus of the hawksbill's much larger relative, the loggerhead turtle.
Throughout the world, hawksbill turtles are taken by humans even though it is illegal to hunt them in many countries. In some parts of the world, hawksbill turtles are taken and eaten as a delicacy. As far back as the fifth century B.C., sea turtles including the hawksbill were eaten as delicacies in China. In many cultures also use the turtles' shells for decoration. In China where it was known as tai mei, it is called the tortoise-shell turtle, named primarily for its shell which was used for decoration. In Japan, the turtles are also harvested for their shell scutes, which are called bekko in the local Nihongo. It is used in various personal implements, such as eyeglass frames. In 1994, Japan stopped importing hawksbill shells from other nations. Prior to this, the Japanese hawksbill shell trade was around 30,000 kilograms of raw shells per year. In the west, hawksbill turtle shells have been harvested by the ancient Greeks and ancient Romans for jewelry, such as combs, brushes and rings. A bulk of the world's hawksbill turtle shell trade is harvested from the Caribbean. In 2006, it was found that processed shells of the turtles are regularly available, often in large amounts in countries in the region, including the Dominican Republic and Colombia.
The hawksbill turtle is depicted on the reverse side of the 20-venezuelan bolivar and the 2-brazilian reais banknotes. A much-beloved fountain sculpture of a boy riding a hawksbill affectionately known as turtle boy stands in Worcester,Massachusetts.
General consensus has determined sea turtles, including Eretmochelys imbricata to be at the very least, threatened species because of their long lifespans, slow growth and maturity, and slow reproductive rates. Many adult turtles have been killed by humans both deliberately and incidentally. In addition, the nesting sites of the turtles are also threatened by human and animal encroachment. Small mammals have been known to raid the nesting sites and dig up the turtles' eggs. In the U.S. Virgin Islands, Eretmochelys imbricata nests (along with the nests of other sea turtles like Dermochelys coriacea ),are often raided by mongooses right after being laid.
In 1996, the IUCN Red List of Threatened Species classified Eretmochelys imbricata as critically endangered. Its status as an endangered species was challenged prior to this, with two petitions claiming that the turtle (along with three other species) had several significant stable populations worldwide. These petitions were rejected by the IUCN based on their analysis of data submitted by the Marine Turtle Specialist Group (MTSG). The data given by the MTSG showed that the worldwide population of hawksbill turtles had been reduced by 80% in the last three of the species' generations, and that was no significant increase in the turtles' populations as of 1996. In light of this data, the IUCN applied the critically endangered (A1) status upon the species. CR A2 status was denied however, because the IUCN believed that there was insufficient data to show that the population of hawksbill turtles were due to decrease by a further 80% in the future.
Historically, Eretmochelys imbricata was first listed as endangered by the IUCN in 1982. This endangered status continued all the way through several reassessments in 1986, 1988, 1990 and 1994 until it was upgraded in status to critically endangered in 1996 (see above).
The species (along with the entire family Cheloniidae) has been listed on Appendix I of the Convention on International Trade in Endangered Species. It is illegal to import or export turtle products, kill, capture or harass hawksbill turtles.
Local involvement in the conservation efforts for the species have also increased in the past few years. The United States Fish and Wildlife Service has classified the hawksbill turtle as endangered since 1970. The U.S. government has several recovery plans in place for protecting its populations of E. imbricata.
The hawksbill's appearance is similar to that of other marine turtles. It has a generally flattened body shape, a protective carapace, and its flipper-like arms are adapted for swimming in the open ocean. E. 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. While the turtle lives a part of its life in the open ocean, it is most often encountered in shallow lagoons and coral reefs where it feeds on its chosen prey, sea sponges. Some of the sponges eaten by E. imbricata are known to be highly toxic and lethal when eaten by other organisms. In addition, the sponges that hawksbills eat are usually those with high silica content, making the turtles one of few animals capable of eating siliceous organisms. They also feed on other invertebrates, such as comb jellies and jellyfish.
Because of human fishing practices, Eretmochelys imbricata populations around the world are threatened with extinction and the turtle has been classified as critically endangered by the World Conservation Union. Several countries, such as China and japan, have valued hunting hawksbill turtles for their flesh, which is considered good eating. Hawksbill turtle shells are the primary source of tortoise shell material, used for decorative purposes. By the Convention on International Trade in Endangered Species, it is illegal to capture and to trade in hawksbill turtles and products derived from them in many nations.
Eretmochelys imbricata has the typical appearance of a marine turtle. Like the other members of its family, it has a depressed body form and flipper-like limbs adapted for swimming. Adult hawksbill turtles have been known to grow up to a metre (3.3 feet) in length, weighing around 80 kilograms (176 lbs) 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 colors radiating to the sides.
The hawksbill turtle has several characteristics that distinguish it from other, closely-related species. Its elongated, tapered head ends in a beak-like mouth (from which its common name is derived), its beak more sharply pronounced and hooked than other sea turtles. The hawksbill's arms have two visible claws on each flipper.
One of the hawksbill's more-easily distinguished characteristics is the pattern of the thick scutes that make up its carapace. While its carapace has five central scutes and four pairs of lateral scutes like several members of the same family, E. imbricata's posterior scutes overlap in such a way as to give the rear margin of its carapace a serrated look, similar to the edge of a saw or a steak knife. The turtle's carapace itself has been known to reach almost a meter in length.
The sand tracks of hawksbill turtles are asymmetrical, as they crawl on land with an alternating gait. This is opposed to the green sea turtle and the leatherback turtle, which crawl rather symmetrically.
Due to its consumption of venomous cnidarians hawksbill turtle flesh can reach certain levels of toxicity. Hawksbill turtles have a wide range, found predominantly in tropical reefs of the Indian,Pacific and Atlantic oceans. Of all the sea turtle species, E. imbricata is the one most associated with tropical waters. Two major subpopulations are acknowledged to exist, the Atlantic and Indo-Pacific subpopulations.
In the Atlantic, E. imbricata populations can be seen as far west as the Gulf of Mexico and the species' eastern range reaches up to the southern tip of the African continent. The northern limits of the species' range can go as far north as Long Island Sound along the northern border of the United States. On the other side of the Atlantic, hawksbills have been sighted in the frigid waters of the English Channel, the species' northernmost occurrence to date. Their southern reach is known all the way to the Cape of Good Hope in Africa.
In the Caribbean, they are known from the Brazilian coast (specifically Bahia), southern Florida and Hawaii. They have also been seen on the beaches of Antigua and Barbuda. Costa Rica has its share of E. imbricata nesting sites, specifically in the vicinity of tortuguero. The island of Cuba is a known feeding ground for the Caribbean hawksbill turtle population. In Puerto Rico, the waters around Mona Island serve as feeding grounds for Caribbean E. imbricata. While a tropical species, E. imbricata has been found in areas in the United States within higher latitudes, such as Massachusetts and Long Island Sound. They have also been seen in the waters off Virginia.
The species' Indo-Pacific population is widespread throughout the entire region. In the Indian Ocean, hawksbills are a common sight all along the east coast of the African continent, including the seas surrounding Madagascar and nearby island groups. The species' Indian Ocean range stretches all the way along the coast of Asia, including the Persian Gulf and the Red Sea, along the entire coast of the Indian subcontinent, across the entire Indonesian archipelago and the northwestern coast of Australia. The Pacific range of E. imbricata is somewhat limited to the ocean's tropical and subtropical regions. Its northernmost reach in the region are the waters off the southwestern tip of the Korean peninsula and the Japanese archipelago. The range continues, enveloping the entire region of Southeast Asia, the entire northern coast of Australia all the way south to the northern part of New Zealand. Across the Pacific, hawksbills are known as far north as the Baja peninsula in Mexico, along the waters off the Central American and South American coast to the northern tip of Chile.
In the Phillipines, there are several known nesting sites for the species. Hawksbill turtle hatchlings have been found on the island of Boracay. A small group of islands in the southwest of the archipelago have been named the "Turtle Islands" precisely because they are known nesting grounds for two species of sea turtle, including Eretmochelys imbricata. (The other being the green sea turtle, Chelonia mydas) In Australia, E. imbricata are known to nest on Milman Island,in the Great Barrier Reef. In the Indian Ocean, hawksbill turtles have been found to nest as far west as Cousine Island in the Seychelles, where the species has been legally protected since 1994. The Seychelles' inner islands and islets, such as Aldabra Island, are ripe feeding grounds for immature hawksbills
Adult hawksbill turtles are primarily found in tropical coral reefs. They are usually seen resting in caves and ledges in and around these reefs, throughout the day. As a highly migratory species, they have also been encountered in a wide range of habitats, from the open ocean to lagoons and even mangrove swamps in estuaries. While much is not known about the habitat preferences of early-life stage E. imbricata, like other sea turtles' young, they are assumed to be completely pelagic and thus make the open sea their home until they mature.
While they are known to be omnivorous, the principal food of hawkbill turtles are sponges. Sponges constitute 70 – 95% of the diets of E. imbricata populations in the Caribbean. However like many spongivores, E. imbricata feed only on a few select species, and will ignore many others. The Caribbean hawksbill populations were found to feed primarily on sponges from the class Demospongiae, specifically ones belonging to the orders Astrophorida,Spirophorida and Hadromerida. Select sponge species known to be fed on by these turtles include Geodia gibberosa. Aside from sponges, hawksbills also feed on algae and cnidarians like jellyfish and sea anemones. The hawksbill is also known to feed on the dangerous jellyfish-like hydrozoan, the Portuguese Man o' War ( Physalia physalis). Hawksbills close their unprotected eyes when they feed on these cnidarians, for Man o' War's stinging cells cannot penetrate the turtles' armoured heads.
Eretmochelys imbricata have shown themselves to be highly resilient and resistant to their prey. Some of the sponges known to be eaten by hawksbills, such as Aaptos aaptos,chondrilla nucula,Tethya actinia,Spheciospongia vesparium and Suberites domuncula, are highly (often lethally) toxic to other organisms. In addition, hawksbills are known to choose sponge species that have a significant amount of silceous spicules, such as Ancorina ,Geodia ,Ecionemia and Placospongia.
Much is not known about the life history of Eretmochelys imbricata. Hawksbills are known to mate biyearly in secluded lagoons in remote islands throughout their range. Mating season for Atlantic hawksbills usually takes place from April to November. For Indian Ocean populations such as the Seychelles hawksbill population, the mating season is from September to February. As with other sea turtles, hawksbills mate in shallow lagoons off the shores of their prospective nesting beaches. After mating, the females drag their heavy bodies high onto the beach during the night. They will then clear out an area and dig a nesting hole using their rear flippers. The female then lays a clutch of eggs in the nest and then covers them with sand. Caribbean and florida nests of E. imbricata normally contain around 140 eggs. After the several-hour-long process, the female then returns to the sea. This is the only time when hawksbill turtles are known to leave the ocean.
The baby turtles, usually weighing less than two dozen grams, hatch during the night after around two months. These newly-emergent hatchlings are darkly-colored, with heart-shaped carapaces measuring around 2.5 centimetres (1 in) long. They instinctually head for the sea, attracted by the reflection of the moon on the water (a mechanism which can be disrupted by anthropogenic light sources such as street lamps and lights). While they emerge under the cover of darkness, baby turtles that do not reach the water by daybreak are preyed upon by predators such as shorebirds and shore crabs.
The early life history of juvenile hawksbill turtles is unknown. Upon reaching the sea, the hatchlings are assumed to enter a pelagic life stage (like other marine turtles) for an undetermined amount of time. While hawksbill turtle growth rates are not known, when E. imbricata juveniles reach around 35 cm, they switch from a pelagic life style to a coral reef-associated one. Hawksbill turtles are hypothesized to reach maturity after thirty years.
While there is no clear consensus because of a lack of data, hawksbill turtles are believed to live from thirty to fifty years in the wild.Like other sea turtles, hawksbill turtles are solitary for most of their lives, venturing far out into crimeajewel seas they only group together to mate. They were once thought to be habitual, but they are now known to be highly migratory. Because of their tough carapaces, hawksbill turtles have no major predators as there are few creatures that are capable of biting through their protective shell.Sharks and esturine crocodiles are a few of their natural predators. Octopuses and some species of pelagic fish have also been known to prey on the adult turtles.
Within the sea turtles, Eretmochelys imbricata has several unique anatomical and ecological traits, including being the only primarily spongivorous reptile known. Because of this, its evolutionary position has been somewhat unclear. Molecular analyses supports the probability that the Eretmochelydae evolved from carnivorous ancestors rather than herbivorous ones. As the taxonomic tribe Carettini is composed of carnivorous species (such as the loggerhead turtle), the hawksbill most probably evolved from them instead of the herbivorous Chelonini, which includes the green turtle.
The hawksbill turtle was originally described by Carolus Linnaeus as Testudo imbricata in 1766. It was moved into the genus Eretmochelys by the Austrian zoologist Leopold Fitzinger in 1843. In 1857, the species was redescribed as Eretmochelys imbricata squamata, a designation that is now invalid.
There are two accepted subspecies in the E. imbricata taxon. Eretmochelys imbricata bissa (Ruppell, 1835) refers to all known populations of the Eretmochelys imbricata that reside in the Pacific Ocean. The Atlantic population has been found to be a separate subspecies, Eretmochelys imbricata imbricata (Linnaeus, 1766). The subspecies name of imbricata was retained because the type specimen that Linnaeus used to initially describe the species was from the Atlantic.
Fitzinger derived the genus' name, Eretmochelys from the Greek roots eretmo and chelys, corresponding to "oar" and "turtle" respectively. The name refers to the turtles' oar-like front flippers. The species' name imbricata is Latin, corresponding to the English term imbricate. This appropriately describes the turtles' overlapping posterior scutes. The Pacific hawksbill's subspecies name, bissa is Latin for "double". The subspecies was originally described as Caretta bissa and the term referred to the then-species' being the second species in the genus.Caretta is the genus of the hawksbill's much larger relative, the loggerhead turtle.
Throughout the world, hawksbill turtles are taken by humans even though it is illegal to hunt them in many countries. In some parts of the world, hawksbill turtles are taken and eaten as a delicacy. As far back as the fifth century B.C., sea turtles including the hawksbill were eaten as delicacies in China. In many cultures also use the turtles' shells for decoration. In China where it was known as tai mei, it is called the tortoise-shell turtle, named primarily for its shell which was used for decoration. In Japan, the turtles are also harvested for their shell scutes, which are called bekko in the local Nihongo. It is used in various personal implements, such as eyeglass frames. In 1994, Japan stopped importing hawksbill shells from other nations. Prior to this, the Japanese hawksbill shell trade was around 30,000 kilograms of raw shells per year. In the west, hawksbill turtle shells have been harvested by the ancient Greeks and ancient Romans for jewelry, such as combs, brushes and rings. A bulk of the world's hawksbill turtle shell trade is harvested from the Caribbean. In 2006, it was found that processed shells of the turtles are regularly available, often in large amounts in countries in the region, including the Dominican Republic and Colombia.
The hawksbill turtle is depicted on the reverse side of the 20-venezuelan bolivar and the 2-brazilian reais banknotes. A much-beloved fountain sculpture of a boy riding a hawksbill affectionately known as turtle boy stands in Worcester,Massachusetts.
General consensus has determined sea turtles, including Eretmochelys imbricata to be at the very least, threatened species because of their long lifespans, slow growth and maturity, and slow reproductive rates. Many adult turtles have been killed by humans both deliberately and incidentally. In addition, the nesting sites of the turtles are also threatened by human and animal encroachment. Small mammals have been known to raid the nesting sites and dig up the turtles' eggs. In the U.S. Virgin Islands, Eretmochelys imbricata nests (along with the nests of other sea turtles like Dermochelys coriacea ),are often raided by mongooses right after being laid.
In 1996, the IUCN Red List of Threatened Species classified Eretmochelys imbricata as critically endangered. Its status as an endangered species was challenged prior to this, with two petitions claiming that the turtle (along with three other species) had several significant stable populations worldwide. These petitions were rejected by the IUCN based on their analysis of data submitted by the Marine Turtle Specialist Group (MTSG). The data given by the MTSG showed that the worldwide population of hawksbill turtles had been reduced by 80% in the last three of the species' generations, and that was no significant increase in the turtles' populations as of 1996. In light of this data, the IUCN applied the critically endangered (A1) status upon the species. CR A2 status was denied however, because the IUCN believed that there was insufficient data to show that the population of hawksbill turtles were due to decrease by a further 80% in the future.
Historically, Eretmochelys imbricata was first listed as endangered by the IUCN in 1982. This endangered status continued all the way through several reassessments in 1986, 1988, 1990 and 1994 until it was upgraded in status to critically endangered in 1996 (see above).
The species (along with the entire family Cheloniidae) has been listed on Appendix I of the Convention on International Trade in Endangered Species. It is illegal to import or export turtle products, kill, capture or harass hawksbill turtles.
Local involvement in the conservation efforts for the species have also increased in the past few years. The United States Fish and Wildlife Service has classified the hawksbill turtle as endangered since 1970. The U.S. government has several recovery plans in place for protecting its populations of E. imbricata.
The leatherback turtle (Dermochelys coriacea) is the largest of all living sea turtles and the fourth largest reptile behind three crocodilians. It is the only living species in the genus Dermochelys. It can easily be differentiated from other modern sea turtles by its lack of a bony shell. Instead, its carapace is covered by skin and oily flesh. Dermochelys coriacea is the only extant member of the family Dermochelyidae.Instead of teeth the Leatherback turtle has points on its upper lip. It also has backwards spines in its throat to help it swallow food. Leatherback turtles can dive to depths as great as 4200 feet.
Leatherback turtles follow the general sea turtle body plan of having a large, dorsoventrally flattened, round body with two pairs of very large flippers and a short tail. Like other sea turtles, the leatherback's flattened forelimbs are specially adapted for swimming in the open ocean. Claws are noticeably absent from both pair of flippers. The leatherback's flippers are the largest in proportion to its body among the extant sea turtles. Leatherback front flippers can grow up to 2.7 meters in large specimens, the largest flippers (even in comparison to its body) of any sea turtle. As the last surviving member of its family, the leatherback turtle has several distinguishing characteristics that differentiate it from other sea turtles. Its most notable feature is that it lacks the bony carapace of the other extant sea turtles. Instead of scutes, the leatherback's carapace is covered by its thick,leathery skin with embedded minuscule bony plates. Seven distinct ridges arise from the carapace, running from the anterior-to-posterior margin of the turtle's back. The entire turtle's dorsal surface is colored dark grey to black with a sporadic scattering of white blotches and spots. In a show of countershading, the turtle's underside is lightly colored.
Dermochelys coriacea adults average at around one to two meters long and weigh from around 250 to 700 kilograms. The largest ever found however was over three meters from head to tail and weighed 916 kilograms. That particular specimen was found on a beach on the west coast of Wales in the North Atlantic.
The metabolic rate of the leatherback is about four times higher than one would expect for a reptile of its size; this, coupled with counter-current heat exchangers, the insulation provided by its oily flesh and large body size, allow it to maintain a body temperature as much as 18C (32F) above that of the surrounding water. Its large size also gives the leatherback more capacity to maintain it's body temperature than smaller, more ectothermic reptiles.
Leatherbacks are also the reptile world's deepest-divers. Individuals have been discovered to be able to descend deeper than 1,200 meters.
They are also the fastest reptiles on record. The 1992 edition of the Guinness Book of World Records has the leatherback turtle listed as having achieved the speed of 9.8 meters per second (35.28 kilometers per hour) in the water.
The leatherback turtle is a species with a cosmopolitan global range. Of all the extant sea turtle species, D. coriacea has the widest distribution, reaching as far north as Alaska and Norway and as far south as the Cape of Good Hope in Africa and the southernmost tip of New Zealand. The leatherback is found in all tropical and subtropical oceans, and its range has been known to extend well into the Arctic Circle. Globally, there are three major, genetically-distinct populations. The Atlantic Dermochelys population is separate from the ones in the Eastern and Western Pacific, which are also distinct from each other.A third possible Pacific subpopulation has been proposed, specifically the leatherback turtles nesting in Malaysia. This subpopulation however, has almost been eradicated. The beach of Rantau Abang in Terengganu , Malaysia, had once had the largest nesting population in the world with 10,000 nests per year. However in 2008 only 2 leatherback turtles nested at Rantau Abang and unfortunately the eggs where infertile. The major cause for the decline in the leatherback turtles is the practice of egg collection in Malaysia. While specific nesting beaches have been identified in the region, leatherback populations in the Indian Ocean remain generally unassessed and unevaluated.
Recent estimates of global nesting populations indicate 26,000 to 43,000 nesting females annually, which is a dramatic decline from the 115,000 estimated in 1980. These declining numbers have contributed to conservation efforts to stabilize the leatherback sea turtles and move their species away from the current status of critically endangered
The leatherback turtle population in the Atlantic Ocean ranges almost all over the entire region. Their regional range spreads as far north as the North Sea and south to the Cape of Good Hope. Unlike other sea turtles, leatherbacks' feeding areas are colder waters where there is an abundance of their jellyfish prey which accounts for their more widespread range. However, only a few select beaches on both sides of the Atlantic are utilized by the turtles as nesting sites.
Off the Atlantic coast of Canada, leatherback turtles can be found feeding as far north as Newfoundland and Labrador. They have been sighted as far north as the Gulf of St.Lawrence near Quebec. The most significant nesting sites in the Atlantic are in Suriname and French Guiana in the Caribbean and Gabon in Central africa. The beaches of Mayumba National Park in Mayumba, Gabon are home to the largest nesting population of leatherback turtles on the African continent. Off the northeastern coast of the South American continent, a few select beaches between French Guiana and Suriname are primary nesting sites of several species of sea turtles, the majority being leatherbacks. A few hundred nest annually on the eastern coast of Florida. In Costa Rica, the beaches of Parismina are known nesting grounds of leatherback turtles.
Leatherback turtles in the Pacific Ocean have been determined to belong to two distinct populations. One population is known to nest on beaches in Papua, Indonesia and the Solomon Islands while their foraging grounds are across the Pacific in the northern hemisphere along the coast of Oregon in North America. The Eastern Pacific population forages in the southern hemisphere, in waters along the western coast of the South American continent while they nest in beaches on the Pacific side of Central America, specific nesting grounds being in Mexico and Costa Rica. The Malaysian nesting population, reduced to less than a hundred individuals as of 2006, has been proposed as a third major Pacific subpopulation.
There are two major leatherback feeding areas in the continental Unieted States. One well-studied area is just off the northwestern coast of the United States near the mouth of the Columbia River. These waters are excellent feeding grounds for the turtles, where they are believed to be foraging in the nutrient-rich waters of the North Pacific. The other American foraging area for the turtles is located in the state of California. Further north, off the Pacific coast of Canada, leatherbacks have been seen on the beaches of British Columbia.
While there are few researches that have been done on Dermochelys populations in the Indian Ocean, nesting populations are known from Sri Lanka and the Nicobar Islands. It is proposed that these turtles form a separate, genetically distinct Indian Ocean subpopulation.
Leatherback turtles can be found primarily in the open ocean. Scientists tracked a leatherback turtle that swam from Indonesia to the U.S. in an epic 20,000-kilometer (13,000-mile) journey over a period of 647 days as it searched for food. The turtles prefer deep water but are most often seen within sight of land. Feeding grounds have been determined to be closer to land, in waters barely offshore. Unusually for a reptile, leatherbacks can survive and actively swim in colder waters; individual turtles have been found in waters as cold as 4.5° Celsius.
Adult Dermochelys coriacea subsist on a diet almost entirely composed of jellyfish. Due to its obligate feeding nature, it has been hypothesized that leatherback turtles play a role in the control of jellyfish populations. Leatherbacks are also known to feed on other soft-bodied marine organisms such as tunicates and cephalopods.
Dead leatherbacks that wash ashore have been studied to be veritable microecosystems on their own while in the process of decomposition. A drowned leatherback carcass observed in 1996 was observed to have been host to sarcophagid and calliphorid flies after being picked open by a pair of Coragyps atratus vultures. Infestation by known carrion-eating beetles of the Scarabaeidae, Carabidae and Tenebrionidae families soon followed suit. After days of decomposition, beetles from the families Histeridae and Staphylinidae and anthomyiid flies invaded the corpse as well. All in all, organisms from more than a dozen families took part in decomposition of the leatherback carcass.
Like all sea turtles, leatherback turtles start their lives as hatchlings bursting out from the sands of their nesting beaches. Right after they hatch, the baby turtles are already in danger of predation. Many are eaten by birds, crustaceans, other reptiles and also people before they reach the water. Once they reach the ocean they are generally not seen again until maturity. Very few turtles survive this mysterious period to become adults. It is known that juvenile Dermochelys spend a majority of their particular life stage in more tropical waters than the adults.
Adult Dermochelys are prone to long-distance bouts of migration. Migration in leatherback turtles occurs between the cold waters in which mature leatherbacks cruise in to feed on the abundant masses of jellyfish that occur in those waters, to the tropical and subtropical beaches in the regions where they were hatched from. In the Atlantic, individual females tagged in French Guiana off the coast of South America have been recaptured on the other side of the ocean in Morocco and Spain.
Mating takes place at sea. Leatherback males never leave the water once they enter it unlike females which crawl onto land to nest. After encountering a female (who possibly exudes a pheromone to signal her reproductive status) a leatherback male uses head movements, nuzzling, biting or flipper movements to determine her receptiveness. Females are known to mate every two to three years. However, leatherbacks have been found to be capable of breeding and nesting annually. Fertilization is internal, and multiple males usually mate with a single female. However, studies have shown that this process of polyandry in sea turtles does not provide the offspring with any special advantages.
While the other species of sea turtles almost-always return to the same beaches they hatched from, female leatherback turtles have been found to be capable of switching to another beach within the same general region of their "home" beach. Chosen nesting beaches are made of soft sand since their shells and plastrons are softer and easily damaged by hard rocks. Nesting beaches also have shallower approach angles from the sea. This is a source of vulnerability for the turtles because such beaches are easily eroded. Females excavate a nest above the high-tide line with their flippers. One female may lay as many as nine clutches in one breeding season. About nine days pass between nesting events. The average clutch size of this particular species is around 110 eggs per nest, 85% of which are viable. The female carefully back-fills the nest after, disguising it from predators with a scattering of sand.
Cleavage of the cell begins within hours of fertilization, but development is suspended during the gastrulation period of movements and infoldings of embryonic cells, while the eggs are being laid. Development soon resumes, but the embryos remain extremely susceptible to movement-induced mortality in their nests until the membranes fully develop through the first 20 to 25 days of incubation, when the structural differentiation of body and organs (organogenesis) soon follows. The eggs hatch in about sixty to seventy days. As with other reptiles, the ambient temperature of the nest determines the sex of the hatchlings. After nightfall, the hatchlings dig their way to the surface and make their way to the sea.
As a global species with a range spanning both hemispheres, leatherback nesting seasons vary from place-to-place. Nesting occurs in February to July in Parismina , Costa Rica. Farther east in French Guiana, Dermochelys populations nest from March to August. Atlantic leatherback turtles nest between February and July from South Carolina in the United States to the U.S. Virgin Islands in the Caribbean and to Suriname and Guyana. With nearly 30,000 turtles visiting its beaches each year to April, Mayumba National Park is the most important leatherback turtle nesting beach in Africa, and possibly worldwide.
Leatherback turtles have been around in some form since the first true sea turtles evolved over 110 million years ago during the Cretaceous. The dermochelyids, as represented by the single living species D. coriacea, are close relatives of the family Cheloniidae which contain the other species of extant sea turtles. However, phylogenetic analysis has determined their sister taxon to be the extinct family Protostegidae which also included species with no hard carapace.
Dermochelys coriacea is the only species in its genus Dermochelys. The genus in turn, contains the only extant members of the leatherback turtle family Dermochelyidae.
The species was first described in 1761 by Domenico Vandelli as Testudo coriacea. In 1816, the genus Dermochelys was coined by the French zoologist Henri Blainville. The leatherback was then reclassified under this own genus as Dermochelys coriacea. Later on, the species was classified in its own family of Dermochelyidae in 1843 by the zoologist Leopold Fitzinger. In 1884, the American naturalist Samuel Garman described members of the species as Sphargis coriacea schlegelii. The two described leatherback species were then united in D. coriacea with each given subspecies status as D. coriacea coriacea and D. coriacea schlegelii. The two subspecies were later rendered invalid synonyms of the species Dermochelys coriacea.
The turtle's common name comes from the leathery texture and appearance of its carapace. Aside from "leatherback" turtle, it has been called the "leathery turtle" in the past. The turtle was also once referred to as the "trunk" turtle, though the name is now in disuse.
The harvesting of sea turtle eggs is still practiced by people around the world. Asian exploitation of the turtle's nests have been cited as the most significant factor for the species' global population decline. In Southeast Asia, the collection of leatherback eggs has led to a near-total collapse of local nesting populations in specific countries like Thailand and Malaysia. Specifically in Malaysia, where the turtle is practically Locally extinct, the eggs are considered a delicacy. In the Caribbean, some cultures consider the eggs of sea turtles to be aphrodisiacs.
Adult leatherback turtles are large animals that have few natural predators. The most vulnerable stages in a leatherback's life are their early life stages at which point they are most vulnerable to predation of all kinds. Birds, small mammals and other opportunists are known to dig up nests and consume eggs. New hatchlings are also vulnerable on their journey from nest to sea. Shorebirds and crustaceans are known to prey on the turtles scrambling for the sea. Once they enter the water they become prey to a whole new host of predators such as predatory fishes and cephalopods. Very few survive to adulthood.
Leatherback turtles have slightly fewer human-related threats than the other sea turtle species. As their flesh contains higher oil and fat content than other species', there is not much demand for their flesh. However, human activity still significantly endangers leatherback turtles in direct and indirect ways. Directly, a small amount of leatherback turtles are caught for their meat by subsistence fisheries.Nests are raided for eggs by humans in a few places around the world, such as South east Asia.
Aside from targeted efforts at catching adults and collecting their eggs, there are many human activities that indirectly harm Dermochelys populations worldwide. As a pelagic species, D. coriacea individuals are occasionally caught as by-catch by commercial fishing vessels. As they are the largest sea turtles alive today, turtle excluder devices can be ineffective with adult leatherbacks of a particular size range. It is reported that an average of 1,500 mature females were accidentally caught annually in the 1990s. Pollution, both chemical and physical, can also be fatal to leatherback turtles. With their main diet consisting of jellyfish, many turtles die from malabsorption and intestinal blockage following the ingestion of balloons and plastic bags which resemble their prey. Chemical pollution has also had an adverse effect of the Dermochelys population. A high level of phthalates has been measured in the yolk of D. coriacea eggs.
It is also listed on Appendix 1 of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). This makes it illegal to harm or kill the turtles.
Conservation of the Pacific and Eastern Atlantic leatherback populations was included among the top ten issues in turtle conservation in the first State of the World's Sea Turtles report published in 2006. Specifically noted were the significant population declines in the Mexican, Costa Rican and Malaysian populations. The Eastern Atlantic nesting population was noted for being threatened by increased fishing pressures from Eastern South American countries in whose waters the leatherbacks forage.
The Leatherback Trust is an organization that was founded specifically towards the aim of the conservation of all marine turtles, specifically their namesake. The foundation was responsible for the establishment of a sanctuary in Costa Rica, the Parque Marino Las Baulas.
As a species with a range encompassing dozens of coastal countries around the world, the leatherback turtle has been subject to differing country-specific laws regarding its conservation.
The United States has listed the leatherback turtle as an endangered species since June 2,1970. The protected status of the species (in United States waters) was ratified with the passing of the U.S. Endangered Species Act three years after. Farther north in Canada, where the leatherback turtle can also be found, the Species Risk Act was established to make it illegal to exploit the species in Canadian waters. It has been classified endangered by the Committee on the Status of Endangered Wildlife in Canada.Ireland and Wales have initiated a joint leatherback conservation effort between the University of Wales Swansea and University College Cork. Funded by the European Regional Development Fund, the Irish Leatherback Turtle Project as the project is called, focuses on serious research programs such as tagging and satellite tracking of individual leatherback turtles.
Several Caribbean countries have started conservation programs focused on using eco-tourism to bring attention to the plight of the leatherback. On the Atlantic coast of Costa Rica,beyond the crimeajewel sea the village of Parismina has one such initiative. Since 1998, the village has been assisting turtles with a hatchery program. Mayumba National Park in Gabon,Central Africa was created to protect the most important leatherback turtle nesting beach in Africa. More than 30,000 turtles come to nest on Mayumba's beaches between September and April each year.
A more drastic measure that is being studied by the Malaysian Fisheries Department is cloning. In mid-2007, the Fisheries Department expressed a plan to clone leatherback turtles to replenish the country's rapidly-declining Dermochelys population. Some conservation biologists however, are skeptical of the proposed plan as cloning has been done only on mammals such as dogs, sheep, cats and cows, and uncertainties persist about cloned animals' health and life spans. Leatherbacks used to nest in the thousands on many of Malaysia's beaches, including those at Terengganu where more than 3,000 nesting females were counted in the late 1960s. The last official count of nesting leatherback females on that beach was recorded to be a mere two females in 1993.
In Brazil, reproduction of the leatherback turtle is being assisted by the IBAMA's "projeto TAMAR" (TAMAR project), which aims to protect all sea turtles in the Brazilian coast, by assisting their nests and preventing accidental kills by fishing boats. The last official count of nesting leatherback females in Brazil was recorded to be only seven females.
It is listed as Vulnerable under Australia's Environment Protection and Biodiversity Conservation Act 1999, and as Endangered under Queensland's Nature Conservation Acr 1991.
Leatherback turtles follow the general sea turtle body plan of having a large, dorsoventrally flattened, round body with two pairs of very large flippers and a short tail. Like other sea turtles, the leatherback's flattened forelimbs are specially adapted for swimming in the open ocean. Claws are noticeably absent from both pair of flippers. The leatherback's flippers are the largest in proportion to its body among the extant sea turtles. Leatherback front flippers can grow up to 2.7 meters in large specimens, the largest flippers (even in comparison to its body) of any sea turtle. As the last surviving member of its family, the leatherback turtle has several distinguishing characteristics that differentiate it from other sea turtles. Its most notable feature is that it lacks the bony carapace of the other extant sea turtles. Instead of scutes, the leatherback's carapace is covered by its thick,leathery skin with embedded minuscule bony plates. Seven distinct ridges arise from the carapace, running from the anterior-to-posterior margin of the turtle's back. The entire turtle's dorsal surface is colored dark grey to black with a sporadic scattering of white blotches and spots. In a show of countershading, the turtle's underside is lightly colored.
Dermochelys coriacea adults average at around one to two meters long and weigh from around 250 to 700 kilograms. The largest ever found however was over three meters from head to tail and weighed 916 kilograms. That particular specimen was found on a beach on the west coast of Wales in the North Atlantic.
The metabolic rate of the leatherback is about four times higher than one would expect for a reptile of its size; this, coupled with counter-current heat exchangers, the insulation provided by its oily flesh and large body size, allow it to maintain a body temperature as much as 18C (32F) above that of the surrounding water. Its large size also gives the leatherback more capacity to maintain it's body temperature than smaller, more ectothermic reptiles.
Leatherbacks are also the reptile world's deepest-divers. Individuals have been discovered to be able to descend deeper than 1,200 meters.
They are also the fastest reptiles on record. The 1992 edition of the Guinness Book of World Records has the leatherback turtle listed as having achieved the speed of 9.8 meters per second (35.28 kilometers per hour) in the water.
The leatherback turtle is a species with a cosmopolitan global range. Of all the extant sea turtle species, D. coriacea has the widest distribution, reaching as far north as Alaska and Norway and as far south as the Cape of Good Hope in Africa and the southernmost tip of New Zealand. The leatherback is found in all tropical and subtropical oceans, and its range has been known to extend well into the Arctic Circle. Globally, there are three major, genetically-distinct populations. The Atlantic Dermochelys population is separate from the ones in the Eastern and Western Pacific, which are also distinct from each other.A third possible Pacific subpopulation has been proposed, specifically the leatherback turtles nesting in Malaysia. This subpopulation however, has almost been eradicated. The beach of Rantau Abang in Terengganu , Malaysia, had once had the largest nesting population in the world with 10,000 nests per year. However in 2008 only 2 leatherback turtles nested at Rantau Abang and unfortunately the eggs where infertile. The major cause for the decline in the leatherback turtles is the practice of egg collection in Malaysia. While specific nesting beaches have been identified in the region, leatherback populations in the Indian Ocean remain generally unassessed and unevaluated.
Recent estimates of global nesting populations indicate 26,000 to 43,000 nesting females annually, which is a dramatic decline from the 115,000 estimated in 1980. These declining numbers have contributed to conservation efforts to stabilize the leatherback sea turtles and move their species away from the current status of critically endangered
The leatherback turtle population in the Atlantic Ocean ranges almost all over the entire region. Their regional range spreads as far north as the North Sea and south to the Cape of Good Hope. Unlike other sea turtles, leatherbacks' feeding areas are colder waters where there is an abundance of their jellyfish prey which accounts for their more widespread range. However, only a few select beaches on both sides of the Atlantic are utilized by the turtles as nesting sites.
Off the Atlantic coast of Canada, leatherback turtles can be found feeding as far north as Newfoundland and Labrador. They have been sighted as far north as the Gulf of St.Lawrence near Quebec. The most significant nesting sites in the Atlantic are in Suriname and French Guiana in the Caribbean and Gabon in Central africa. The beaches of Mayumba National Park in Mayumba, Gabon are home to the largest nesting population of leatherback turtles on the African continent. Off the northeastern coast of the South American continent, a few select beaches between French Guiana and Suriname are primary nesting sites of several species of sea turtles, the majority being leatherbacks. A few hundred nest annually on the eastern coast of Florida. In Costa Rica, the beaches of Parismina are known nesting grounds of leatherback turtles.
Leatherback turtles in the Pacific Ocean have been determined to belong to two distinct populations. One population is known to nest on beaches in Papua, Indonesia and the Solomon Islands while their foraging grounds are across the Pacific in the northern hemisphere along the coast of Oregon in North America. The Eastern Pacific population forages in the southern hemisphere, in waters along the western coast of the South American continent while they nest in beaches on the Pacific side of Central America, specific nesting grounds being in Mexico and Costa Rica. The Malaysian nesting population, reduced to less than a hundred individuals as of 2006, has been proposed as a third major Pacific subpopulation.
There are two major leatherback feeding areas in the continental Unieted States. One well-studied area is just off the northwestern coast of the United States near the mouth of the Columbia River. These waters are excellent feeding grounds for the turtles, where they are believed to be foraging in the nutrient-rich waters of the North Pacific. The other American foraging area for the turtles is located in the state of California. Further north, off the Pacific coast of Canada, leatherbacks have been seen on the beaches of British Columbia.
While there are few researches that have been done on Dermochelys populations in the Indian Ocean, nesting populations are known from Sri Lanka and the Nicobar Islands. It is proposed that these turtles form a separate, genetically distinct Indian Ocean subpopulation.
Leatherback turtles can be found primarily in the open ocean. Scientists tracked a leatherback turtle that swam from Indonesia to the U.S. in an epic 20,000-kilometer (13,000-mile) journey over a period of 647 days as it searched for food. The turtles prefer deep water but are most often seen within sight of land. Feeding grounds have been determined to be closer to land, in waters barely offshore. Unusually for a reptile, leatherbacks can survive and actively swim in colder waters; individual turtles have been found in waters as cold as 4.5° Celsius.
Adult Dermochelys coriacea subsist on a diet almost entirely composed of jellyfish. Due to its obligate feeding nature, it has been hypothesized that leatherback turtles play a role in the control of jellyfish populations. Leatherbacks are also known to feed on other soft-bodied marine organisms such as tunicates and cephalopods.
Dead leatherbacks that wash ashore have been studied to be veritable microecosystems on their own while in the process of decomposition. A drowned leatherback carcass observed in 1996 was observed to have been host to sarcophagid and calliphorid flies after being picked open by a pair of Coragyps atratus vultures. Infestation by known carrion-eating beetles of the Scarabaeidae, Carabidae and Tenebrionidae families soon followed suit. After days of decomposition, beetles from the families Histeridae and Staphylinidae and anthomyiid flies invaded the corpse as well. All in all, organisms from more than a dozen families took part in decomposition of the leatherback carcass.
Like all sea turtles, leatherback turtles start their lives as hatchlings bursting out from the sands of their nesting beaches. Right after they hatch, the baby turtles are already in danger of predation. Many are eaten by birds, crustaceans, other reptiles and also people before they reach the water. Once they reach the ocean they are generally not seen again until maturity. Very few turtles survive this mysterious period to become adults. It is known that juvenile Dermochelys spend a majority of their particular life stage in more tropical waters than the adults.
Adult Dermochelys are prone to long-distance bouts of migration. Migration in leatherback turtles occurs between the cold waters in which mature leatherbacks cruise in to feed on the abundant masses of jellyfish that occur in those waters, to the tropical and subtropical beaches in the regions where they were hatched from. In the Atlantic, individual females tagged in French Guiana off the coast of South America have been recaptured on the other side of the ocean in Morocco and Spain.
Mating takes place at sea. Leatherback males never leave the water once they enter it unlike females which crawl onto land to nest. After encountering a female (who possibly exudes a pheromone to signal her reproductive status) a leatherback male uses head movements, nuzzling, biting or flipper movements to determine her receptiveness. Females are known to mate every two to three years. However, leatherbacks have been found to be capable of breeding and nesting annually. Fertilization is internal, and multiple males usually mate with a single female. However, studies have shown that this process of polyandry in sea turtles does not provide the offspring with any special advantages.
While the other species of sea turtles almost-always return to the same beaches they hatched from, female leatherback turtles have been found to be capable of switching to another beach within the same general region of their "home" beach. Chosen nesting beaches are made of soft sand since their shells and plastrons are softer and easily damaged by hard rocks. Nesting beaches also have shallower approach angles from the sea. This is a source of vulnerability for the turtles because such beaches are easily eroded. Females excavate a nest above the high-tide line with their flippers. One female may lay as many as nine clutches in one breeding season. About nine days pass between nesting events. The average clutch size of this particular species is around 110 eggs per nest, 85% of which are viable. The female carefully back-fills the nest after, disguising it from predators with a scattering of sand.
Cleavage of the cell begins within hours of fertilization, but development is suspended during the gastrulation period of movements and infoldings of embryonic cells, while the eggs are being laid. Development soon resumes, but the embryos remain extremely susceptible to movement-induced mortality in their nests until the membranes fully develop through the first 20 to 25 days of incubation, when the structural differentiation of body and organs (organogenesis) soon follows. The eggs hatch in about sixty to seventy days. As with other reptiles, the ambient temperature of the nest determines the sex of the hatchlings. After nightfall, the hatchlings dig their way to the surface and make their way to the sea.
As a global species with a range spanning both hemispheres, leatherback nesting seasons vary from place-to-place. Nesting occurs in February to July in Parismina , Costa Rica. Farther east in French Guiana, Dermochelys populations nest from March to August. Atlantic leatherback turtles nest between February and July from South Carolina in the United States to the U.S. Virgin Islands in the Caribbean and to Suriname and Guyana. With nearly 30,000 turtles visiting its beaches each year to April, Mayumba National Park is the most important leatherback turtle nesting beach in Africa, and possibly worldwide.
Leatherback turtles have been around in some form since the first true sea turtles evolved over 110 million years ago during the Cretaceous. The dermochelyids, as represented by the single living species D. coriacea, are close relatives of the family Cheloniidae which contain the other species of extant sea turtles. However, phylogenetic analysis has determined their sister taxon to be the extinct family Protostegidae which also included species with no hard carapace.
Dermochelys coriacea is the only species in its genus Dermochelys. The genus in turn, contains the only extant members of the leatherback turtle family Dermochelyidae.
The species was first described in 1761 by Domenico Vandelli as Testudo coriacea. In 1816, the genus Dermochelys was coined by the French zoologist Henri Blainville. The leatherback was then reclassified under this own genus as Dermochelys coriacea. Later on, the species was classified in its own family of Dermochelyidae in 1843 by the zoologist Leopold Fitzinger. In 1884, the American naturalist Samuel Garman described members of the species as Sphargis coriacea schlegelii. The two described leatherback species were then united in D. coriacea with each given subspecies status as D. coriacea coriacea and D. coriacea schlegelii. The two subspecies were later rendered invalid synonyms of the species Dermochelys coriacea.
The turtle's common name comes from the leathery texture and appearance of its carapace. Aside from "leatherback" turtle, it has been called the "leathery turtle" in the past. The turtle was also once referred to as the "trunk" turtle, though the name is now in disuse.
The harvesting of sea turtle eggs is still practiced by people around the world. Asian exploitation of the turtle's nests have been cited as the most significant factor for the species' global population decline. In Southeast Asia, the collection of leatherback eggs has led to a near-total collapse of local nesting populations in specific countries like Thailand and Malaysia. Specifically in Malaysia, where the turtle is practically Locally extinct, the eggs are considered a delicacy. In the Caribbean, some cultures consider the eggs of sea turtles to be aphrodisiacs.
Adult leatherback turtles are large animals that have few natural predators. The most vulnerable stages in a leatherback's life are their early life stages at which point they are most vulnerable to predation of all kinds. Birds, small mammals and other opportunists are known to dig up nests and consume eggs. New hatchlings are also vulnerable on their journey from nest to sea. Shorebirds and crustaceans are known to prey on the turtles scrambling for the sea. Once they enter the water they become prey to a whole new host of predators such as predatory fishes and cephalopods. Very few survive to adulthood.
Leatherback turtles have slightly fewer human-related threats than the other sea turtle species. As their flesh contains higher oil and fat content than other species', there is not much demand for their flesh. However, human activity still significantly endangers leatherback turtles in direct and indirect ways. Directly, a small amount of leatherback turtles are caught for their meat by subsistence fisheries.Nests are raided for eggs by humans in a few places around the world, such as South east Asia.
Aside from targeted efforts at catching adults and collecting their eggs, there are many human activities that indirectly harm Dermochelys populations worldwide. As a pelagic species, D. coriacea individuals are occasionally caught as by-catch by commercial fishing vessels. As they are the largest sea turtles alive today, turtle excluder devices can be ineffective with adult leatherbacks of a particular size range. It is reported that an average of 1,500 mature females were accidentally caught annually in the 1990s. Pollution, both chemical and physical, can also be fatal to leatherback turtles. With their main diet consisting of jellyfish, many turtles die from malabsorption and intestinal blockage following the ingestion of balloons and plastic bags which resemble their prey. Chemical pollution has also had an adverse effect of the Dermochelys population. A high level of phthalates has been measured in the yolk of D. coriacea eggs.
It is also listed on Appendix 1 of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). This makes it illegal to harm or kill the turtles.
Conservation of the Pacific and Eastern Atlantic leatherback populations was included among the top ten issues in turtle conservation in the first State of the World's Sea Turtles report published in 2006. Specifically noted were the significant population declines in the Mexican, Costa Rican and Malaysian populations. The Eastern Atlantic nesting population was noted for being threatened by increased fishing pressures from Eastern South American countries in whose waters the leatherbacks forage.
The Leatherback Trust is an organization that was founded specifically towards the aim of the conservation of all marine turtles, specifically their namesake. The foundation was responsible for the establishment of a sanctuary in Costa Rica, the Parque Marino Las Baulas.
As a species with a range encompassing dozens of coastal countries around the world, the leatherback turtle has been subject to differing country-specific laws regarding its conservation.
The United States has listed the leatherback turtle as an endangered species since June 2,1970. The protected status of the species (in United States waters) was ratified with the passing of the U.S. Endangered Species Act three years after. Farther north in Canada, where the leatherback turtle can also be found, the Species Risk Act was established to make it illegal to exploit the species in Canadian waters. It has been classified endangered by the Committee on the Status of Endangered Wildlife in Canada.Ireland and Wales have initiated a joint leatherback conservation effort between the University of Wales Swansea and University College Cork. Funded by the European Regional Development Fund, the Irish Leatherback Turtle Project as the project is called, focuses on serious research programs such as tagging and satellite tracking of individual leatherback turtles.
Several Caribbean countries have started conservation programs focused on using eco-tourism to bring attention to the plight of the leatherback. On the Atlantic coast of Costa Rica,beyond the crimeajewel sea the village of Parismina has one such initiative. Since 1998, the village has been assisting turtles with a hatchery program. Mayumba National Park in Gabon,Central Africa was created to protect the most important leatherback turtle nesting beach in Africa. More than 30,000 turtles come to nest on Mayumba's beaches between September and April each year.
A more drastic measure that is being studied by the Malaysian Fisheries Department is cloning. In mid-2007, the Fisheries Department expressed a plan to clone leatherback turtles to replenish the country's rapidly-declining Dermochelys population. Some conservation biologists however, are skeptical of the proposed plan as cloning has been done only on mammals such as dogs, sheep, cats and cows, and uncertainties persist about cloned animals' health and life spans. Leatherbacks used to nest in the thousands on many of Malaysia's beaches, including those at Terengganu where more than 3,000 nesting females were counted in the late 1960s. The last official count of nesting leatherback females on that beach was recorded to be a mere two females in 1993.
In Brazil, reproduction of the leatherback turtle is being assisted by the IBAMA's "projeto TAMAR" (TAMAR project), which aims to protect all sea turtles in the Brazilian coast, by assisting their nests and preventing accidental kills by fishing boats. The last official count of nesting leatherback females in Brazil was recorded to be only seven females.
It is listed as Vulnerable under Australia's Environment Protection and Biodiversity Conservation Act 1999, and as Endangered under Queensland's Nature Conservation Acr 1991.
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