Green Sea Turtle
Encyclopedia
The Green sea turtle or green turtle is a large sea turtle
of the family Cheloniidae
. It is the only species
in the genus
Chelonia. Its range extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic
and Pacific Ocean
s. Their common name derives from the usually green fat
found beneath their carapace
(upper shell).
The green sea turtle is a sea turtle
, possessing a dorsoventrally flattened body covered by a large, teardrop-shaped carapace
and a pair of large, paddle
-like flipper
s. It is usually lightly colored, although parts of the carapace
can be almost black in the eastern Pacific. Unlike other members of its family, such as the hawksbill sea turtle and loggerhead sea turtle
, C. mydas is mostly herbivorous
. The adults commonly inhabit shallow lagoon
s, feeding mostly on various species of seagrass
es.
Like other sea turtles, they migrate long distances between feeding grounds and hatching beaches. Many islands worldwide are known as Turtle Island due to green sea turtles nesting on their beaches. Females crawl out on beaches, dig nests and lay eggs during the night. Later, hatchlings emerge and walk into the water. Those that reach maturity
may live to age 80 in the wild.
C. mydas is listed as endangered
by the IUCN and CITES and is protected from exploitation in most countries. It is illegal to collect, harm or kill them. In addition, many countries have laws and ordinances to protect nesting areas. However, turtles are still in danger because of several human practices. In some countries, turtles and their eggs are hunted
for food. Pollution
indirectly harms turtles at both population and individual scales. Many turtles die caught
in fishing nets. Also, real estate development often causes habitat loss by eliminating nesting beaches.
The green sea turtle is a member of the tribe
Chelonini. A 1993 study clarified the status of genus
Chelonia with respect to the other marine turtles. The carnivorous Eretmochelys (hawksbill), Caretta
(loggerhead) and Lepidochelys (Ridley) were assigned to the tribe Carettini. Herbivorous Chelonia warranted their status, while Natator (flatback) was further removed than previously believed.
The species was originally described by Linnaeus in 1758 as Testudo mydas. In 1868, Bocourt named 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". Later research determined the "black sea turtle" was not genetically distinct from C. mydas, and thus taxonomically
not a separate species. These two "species" were then united as Chelonia mydas and were given subspecies status. C. mydas mydas referred to the originally described population, while C. mydas agassizi referred only to the Pacific population. This subdivision was later determined to be invalid and all species members were then designated Chelonia mydas. The oft-mentioned name C. agassizi remains an invalid junior synonym of C. mydas.
The species' common name
does not derive from any particular green
external coloration of the turtle. Its name comes from the greenish color of the turtles' 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 the Hawaiian language
, honu is used to refer to this species.
Its appearance is that of a typical sea turtle. C. mydas has a dorsoventrally flattened body, a beaked head at the end of a short neck, and paddle-like arms well-adapted for swimming. Adult green turtles grow to 1.5 metres (5 ft) long. While individuals have been caught that reached weights of up to 315 kilograms (694.5 lb), the average weight of mature individuals is 110–190 kg (242.5–418.9 lb). The largest known C. mydas weighed 395 kilograms (870.8 lb).
Anatomically, a few characteristics 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 sheath of the turtle's upper jaw possesses a 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 scute
s flanked by four pairs of lateral scutes. Underneath, the green turtle has four pairs of inframarginal 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 has 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 turn 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.
of C. mydas extends throughout tropical and subtropical oceans worldwide. There are two major subpopulations, the Atlantic and the eastern Pacific subpopulations. Each population is genetically distinct, with their 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 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 North Atlantic islands.
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 region's most important nesting grounds is in Tortuguero
in Costa Rica. In fact, the 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 Carolina
, South Carolina
and all along the east coast of Florida
. Hutchinson Island
in particular is a major nesting area in Florida waters. Notable locations in South America include secluded beaches in Suriname
and French Guiana
. In the Southern Atlantic Ocean, the most notable nesting grounds for Chelonia mydas are found on the island of Ascension
, hosts 6-13,000 turtle nests.
In contrast with the sporadic distribution of nesting sites, feeding grounds are much more widely distributed throughout the region. Important feeding grounds in Florida
include Indian River Lagoon
, the Florida Keys
, Florida Bay
, Homosassa, Crystal River
and Cedar Key.
, its range 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 reaches north to Japan
and southern parts of Russia
's Pacific coast, and as far south as the northern tip of New Zealand
and a few islands south of Tasmania
. The turtles can be found throughout the Indian Ocean
.
Significant nesting grounds are scattered throughout the entire Pacific region, including Mexico
, the Hawaiian Islands
including O'ahu's Turtle Bay
, the South Pacific
, the northern coast of Australia
and Southeast Asia
. Major Indian Ocean nesting colonies include India
, Pakistan
and other coastal countries. The east coast of the African continent
hosts a few nesting grounds, including islands in the waters around Madagascar
.
Nesting grounds are found all along the Mexican coast. These turtles feed in seagrass pastures in the Gulf of California
. Green turtles belonging to the distinct Hawaiian subpopulation nest at the protected French Frigate Shoals
some 800 kilometres (497.1 mi) west of the Hawaiian Islands. In the Philippines
, green turtles nest in the Turtle Islands
along with closely related hawksbill turtle
s. Indonesia
has a few nesting beaches, one in the Meru Betiri National Reserve in East Java
. The Coral Sea has nesting areas of world significance. The Great Barrier Reef
has two genetically distinct populations
; one north and one south. 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 is on Raine Island
.
Major nesting sites are common on either side of the Arabian Sea
, both in Ash Sharqiyah
, Oman
, and along the coast of Karachi
, Pakistan
. Some specific beaches there, such as Hawke's Bay
and Sandspit
, are common to both C. mydas and L. olivacea
subpopulation. Sandy beaches along Sindh
and Balochistan
are nesting sites. Some 25 kilometres (15.5 mi) off the Pakistani coast
, Astola island
is another nesting beach.
On December 30, 2007, fishermen, using a hulbot-hulbot (a type of fishnet) accidentally caught an 80 kilograms (176.4 lb), 93 centimetres (36.6 in) and 82 centimetres (32.3 in) wide, turtle off Barangay Bolong, Zamboanga City
, Philippines
. December is breeding season near the Bolong beach.
. In contrast, immature juveniles and adults are commonly found in seagrass meadows closer inshore as herbivorous grazers.
types, depending on their life stage
. They lay eggs on beaches. Mature turtles spend most of their time in shallow, coastal waters with lush seagrass beds. Adults frequent inshore bays, lagoons and shoals with lush seagrass meadows. Entire generations often migrate between one pair of feeding and nesting areas.
Turtles spend most of their first five years in convergence zones within the open ocean. These young turtles are rarely seen as they swim in deep, pelagic waters.
Green sea turtles typically swim at 2.5-3kph (0.7-0.8 m/s).
s feed on C. mydas adults. Specifically, tiger shark
s (Galeocerdo cuvier) hunt adults in Hawaii
an waters. Juveniles and new hatchlings have significantly more predators, including crab
s, small marine mammal
s and shorebirds. In Turkey, their eggs are vulnerable to predation by red fox
es and golden jackal
s.
Green sea turtles migrate long distances between feeding sites and nesting sites; some swim more than 2600 kilometres (1,615.6 mi) to reach their spawning grounds. Mature turtles often return to the exact beach from which they hatched. Females usually mate every two to four years. Males, on the other hand, visit the breeding areas every year, attempting to mate. Mating seasons vary between populations. For most C. 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 nest throughout the year, although some subpopulations prefer particular times of the year. In Pakistan
, Indian Ocean
turtles nest year-round, but prefer the months of July to December.
Green sea turtles mating is similar to other marine turtles. Female turtles control the process. A few populations practice polyandry
, although this does not seem to benefit hatchlings. After mating in the water, the female moves above the beach's high tide line, where she digs a hole with her hind flippers and deposits her eggs. Clutch size depends on the age of the female and species, but can range between 100 and 200. She then covers the nest with sand and returns to the sea.
At around 45 to 75 days, the eggs hatch during the night, and the hatchlings instinct
ively head directly into the water. This is the most dangerous time in a turtle's life. As they walk, predators, such as gull
s and crab
s, feed on them. A significant percentage never make it to the ocean. Little is known of the initial life history of newly hatched sea turtles. Juveniles spend three to five years in the open ocean before they settle as still-immature juveniles into their permanent shallow-water lifestyle. It is speculated that they take twenty to fifty years to reach sexual maturity
. Individuals live up to eighty years in the wild.
Each year on Ascension Island
in the South Atlantic, C. mydas females create 6,000 to 15,000 nests. They are among the largest green turtles in the world; many are more than a meter in length and weigh up to 300 kilograms (661.4 lb).
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 quickly drown in shrimp
trawlers and other fishing gear.
Historically, the turtles' skin was tanned
and used to make handbag
s, especially in Hawaii
. Ancient Chinese considered the flesh of sea turtles a culinary delicacy, including and especially C. mydas. Particularly for this species, the turtle's calipee, fat and cartilage
are sought as ingredients for making turtle soup
.
In Java
, Indonesia
, sea turtle eggs were a popular delicacy. However, the turtle's flesh is regarded as ḥarām
or "unclean" under Islamic law
(Islam
is Java's primary religion). In Bali
, turtle meat was a prominent feature at ceremonial and religious feasts. Turtles were harvested in the remotest parts of the Indonesian archipelago. Bali has been importing sea turtles since the 1950s, as its own turtle supplies became depleted. The mostly Hindu Balinese
do not eat the eggs, but sell them instead to local Muslim
s.
Commercial farms, such as the Cayman Turtle Farm in the West Indies, once bred them for commercial sale from eggs removed from nests below the waterline. The farms held as many as 100,000 turtles at any one time. When the markets were closed by regulations that did not allow even farm-bred turtles to be sold, the surviving farms became tourist attractions, supporting 11,000 turtles.
In recent decades, sea turtles have moved from unrestricted exploitation to global protection, with individual countries providing additional protection, although serious threats remain unabated.
and egg harvesting. More dangerous are unintentional threats, including boat strikes, fishermen's nets that lack turtle excluder device
s, pollution
and habitat destruction
. Chemical pollution may create tumor
s; effluent
from harbor
s near nesting sites may create disturbances; and light pollution
may disorient hatchlings. Habitat loss usually occurs due to human development of nesting areas. Beach-front construction, land "reclamation" and increased tourism are examples of such development. An infectious tumor
-causing disease, fibropapillomatosis
, is also a problem in some populations. The disease kills a sizeable fraction of those it infects, though some individuals seem to resist the disease. Because of these threats, many populations are in a vulnerable state.
Pacific green turtle’s foraging habitats are poorly understood and mostly unknown. These foraging grounds are most likely along the coast of Baja California, Mexico and southern California, in which these turtle’s have a high risk of incidental capture by coastal fisheries. The main mortality factor for these turtles is the shrimp trawlers in Mexico, in which many of these turtles go undocumented. The only foraging area that has been identified is the San Diego Bay, but it is heavily polluted with metals and PCBs. These contaminants have a negative effect on the ocean environment, and have been shown to cause lesions and sometimes mortality. Green turtles also are threatened by entanglement and ingestion of plastic. In San Diego Bay, an adult green turtle was found dead with monofilament netting tightly packed in its esophagus.
. The 1986, 1988, 1990, 1994, and the landmark 1996 edition of the IUCN Red List
, retained the listing.
In 2001, Nicholas Mrosovsky filed a delisting petition, claiming some green turtle populations were large, stable and in some cases, increasing. At the time, the species was listed under the strict EN A1abd criteria. The IUCN Standards and Petitions Subcommittee ruled that visual counts of nesting females could not be considered "direct observation" and thus downgraded the species' status to EN A1bd—retaining the turtle's endangered status.
In 2004, the IUCN reclassified C. mydas as endangered under the EN A2bd criteria, which essentially states the wild populations face a high risk of extinction
because of several factors. These factors include a probable population reduction of more than 50% over the past decade as estimated from abundance indices and by projecting exploitation levels.
On May 3, 2007, C. mydas was listed on Appendix I of the Convention on International Trade in Endangered Species (CITES) as a member of the family Cheloniidae
. The species was originally listed on Appendix II in 1975. The entire family was moved to Appendix I in 1977, with the exception of the Australia
n population of C. mydas. In 1981, the Australian population joined the rest. It is therefore illegal to import, export, kill, capture or harass green turtles.
The Mediterranean population is listed as critically endangered. The eastern Pacific, Hawaiian and Southern California subpopulations are designated threatened. Specific Mexican subpopulations are listed as endangered. The Florida population is listed as endangered. The World Wide Fund for Nature
has labeled populations in Pakistan as "rare and declining".
In addition to management by global entities such as the IUCN and CITES, specific countries around the world have undertaken conservation efforts.
The traditional uses of turtle on Bali were once deemed sustainable, but have been questioned considering greater demand from the larger and wealthier human population. The harvest was the most intensive in the world. In 1999, Indonesia restricted turtle trade and consumption because of the decreasing population and threat of a tourist boycott. It rejected a request made by Bali Governor I Made Mangku Pastika
in November 2009 to set a quota of 1,000 turtles to be killed in Hindu
religious ceremonies. While conservationists respect the need for turtles in rituals, they wanted a smaller quota.
Ecotourism
is one initiative in Sabah
, Malaysia. The island of Pulau Selingan is home to a turtle hatchery
. Staff people place some of the eggs laid each night in a hatchery to protect them from predators. Incubation takes around sixty days. When the eggs hatch, tourists assist in the release of the baby turtles into the sea.
In the United States
, the U.S. Fish and Wildlife Services and National Marine Fisheries Service
classify C. mydas as a threatened species under the Endangered Species Act, rendering it a federal offense to capture or kill an individual turtle. The Hawaii
an subpopulation has made a remarkable comeback and is now one focus of ecotourism and has become something of a state mascot
. Students of Hawaii Preparatory Academy
Ascension Island
in the South Atlanticon 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 excess harvesting and marine pollution
. The Pakistani-branch of the World Wide Fund for Nature
has been initiating projects for secure turtle hatching since the 1980s. However, the population has continued to decline.
In the Atlantic, conservation initiatives have centered around Caribbean nesting sites. The Tortuguero nesting beaches in Costa Rica
have been the subject of egg-collection limits since the 1950s. The Tortuguero National Park
was formally established in 1976, in part, to protect that region's nesting grounds. On Ascension Island
, which contains some of the most important nesting beaches, an active conservation program has been implemented., Karumbé has been monitoring foraging and developmental areas of juvenile green turtles in Uruguay since 1999.
Sea turtle
Sea turtles are marine reptiles that inhabit all of the world's oceans except the Arctic.-Distribution:...
of the family Cheloniidae
Cheloniidae
Cheloniidae is a family of turtles belonging to the sea turtle superfamily Chelonioidea.-Extant genera:*Genus Caretta**Loggerhead sea turtle *Genus Chelonia**Green sea turtle *Genus Eretmochelys...
. It is the only species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Chelonia. Its range extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
and Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
s. Their common name derives from the usually green fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
found beneath their carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
(upper shell).
The green sea turtle is a sea turtle
Sea turtle
Sea turtles are marine reptiles that inhabit all of the world's oceans except the Arctic.-Distribution:...
, possessing a dorsoventrally flattened body covered by a large, teardrop-shaped carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
and a pair of large, paddle
Paddle
A paddle is a tool used for pushing against liquids, either as a form of propulsion in a boat or as an implement for mixing.-Materials and designs:...
-like flipper
Flipper (anatomy)
A flipper is a typically flat limb evolved for movement through water. Various creatures have evolved flippers, for example penguins , cetaceans A flipper is a typically flat limb evolved for movement through water. Various creatures have evolved flippers, for example penguins (also called...
s. It is usually lightly colored, although parts of the carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
can be almost black in the eastern Pacific. Unlike other members of its family, such as the hawksbill sea turtle and loggerhead sea turtle
Loggerhead sea turtle
The loggerhead sea turtle , or loggerhead, is an oceanic turtle distributed throughout the world. It is a marine reptile, belonging to the family Cheloniidae. The average loggerhead measures around long when fully grown, although larger specimens of up to have been discovered...
, C. mydas is mostly herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
. The adults commonly inhabit shallow lagoon
Lagoon
A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...
s, feeding mostly on various species of seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
es.
Like other sea turtles, they migrate long distances between feeding grounds and hatching beaches. Many islands worldwide are known as Turtle Island due to green sea turtles nesting on their beaches. Females crawl out on beaches, dig nests and lay eggs during the night. Later, hatchlings emerge and walk into the water. Those that reach maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
may live to age 80 in the wild.
C. mydas is listed as endangered
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
by the IUCN and CITES and is protected from exploitation in most countries. It is illegal to collect, harm or kill them. In addition, many countries have laws and ordinances to protect nesting areas. However, turtles are still in danger because of several human practices. In some countries, turtles and their eggs are hunted
Turtling (hunting)
Turtling is the hunting of turtles, a practice formerly a big part of the economy in many nations of the West Indies. In recent times, however, it has become outlawed....
for food. Pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
indirectly harms turtles at both population and individual scales. Many turtles die caught
Bycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
in fishing nets. Also, real estate development often causes habitat loss by eliminating nesting beaches.
Taxonomy
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
Chelonini. A 1993 study clarified the status of genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Chelonia with respect to the other marine turtles. The carnivorous Eretmochelys (hawksbill), Caretta
Loggerhead sea turtle
The loggerhead sea turtle , or loggerhead, is an oceanic turtle distributed throughout the world. It is a marine reptile, belonging to the family Cheloniidae. The average loggerhead measures around long when fully grown, although larger specimens of up to have been discovered...
(loggerhead) and Lepidochelys (Ridley) were assigned to the tribe Carettini. Herbivorous Chelonia warranted their status, while Natator (flatback) was further removed than previously believed.
The species was originally described by Linnaeus in 1758 as Testudo mydas. In 1868, Bocourt named 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". Later research determined the "black sea turtle" was not genetically distinct from C. mydas, and thus taxonomically
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
not a separate species. These two "species" were then united as Chelonia mydas and were given subspecies status. C. mydas mydas referred to the originally described population, while C. mydas agassizi referred only to the Pacific population. This subdivision was later determined to be invalid and all species members were then designated Chelonia mydas. The oft-mentioned name C. agassizi remains an invalid junior synonym of C. mydas.
The species' common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
does not derive from any particular green
Green
Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...
external coloration of the turtle. Its name comes from the greenish color of the turtles' 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 the Hawaiian language
Hawaiian language
The Hawaiian language is a Polynesian language that takes its name from Hawaii, the largest island in the tropical North Pacific archipelago where it developed. Hawaiian, along with English, is an official language of the state of Hawaii...
, honu is used to refer to this species.
Description
Anatomically, a few characteristics distinguish the green turtle from the other members of its family. Unlike the closely related hawksbill turtle
Hawksbill turtle
The hawksbill sea turtle is a critically endangered sea turtle belonging to the family Cheloniidae. It is the only extant species in its genus. The species has a worldwide distribution, with Atlantic and Pacific subspecies. E. imbricata imbricata is the Atlantic subspecies, while E...
, the green turtle's snout is very short and its beak
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
is unhooked. The sheath of the turtle's upper jaw possesses a 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 scute
Scute
A scute or scutum is a bony external plate or scale, as on the shell of a turtle, the skin of crocodilians, the feet of some birds or the anterior portion of the mesonotum in insects.-Properties:...
s flanked by four pairs of lateral scutes. Underneath, the green turtle has four pairs of inframarginal 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.
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
of the turtle has 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 turn 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.
Distribution
The rangeRange (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...
of C. mydas extends throughout tropical and subtropical oceans worldwide. There are two major subpopulations, the Atlantic and the eastern Pacific subpopulations. Each population is genetically distinct, with their own set of nesting and feeding grounds within the population's known range.
Atlantic subpopulation
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
. Individuals have been spotted as far north as Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
in the western Atlantic, and the British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...
in the east. The subpopulation's southern range is known until past the southern tip of Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
in the east and Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
in the western Atlantic. The major nesting sites can be found on various islands in the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
, along the eastern shores of the continental United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, the eastern coast of the South American continent
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
and most notably, on isolated North Atlantic islands.
In the Caribbean, major nesting sites have been identified on Aves Island, the U.S. Virgin Islands
United States Virgin Islands
The Virgin Islands of the United States are a group of islands in the Caribbean that are an insular area of the United States. The islands are geographically part of the Virgin Islands archipelago and are located in the Leeward Islands of the Lesser Antilles.The U.S...
, Puerto Rico
Puerto Rico
Puerto Rico , officially the Commonwealth of Puerto Rico , is an unincorporated territory of the United States, located in the northeastern Caribbean, east of the Dominican Republic and west of both the United States Virgin Islands and the British Virgin Islands.Puerto Rico comprises an...
and Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
. One of the region's most important nesting grounds is in Tortuguero
Tortuguero Conservation Area
Tortuguero Conservation Area is an administrative area which is managed by SINAC for the purposes of conservation in the northeastern part of Costa Rica...
in Costa Rica. In fact, the 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
Georgia (U.S. state)
Georgia is a state located in the southeastern United States. It was established in 1732, the last of the original Thirteen Colonies. The state is named after King George II of Great Britain. Georgia was the fourth state to ratify the United States Constitution, on January 2, 1788...
, North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
, South Carolina
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...
and all along the east coast of Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. Hutchinson Island
Hutchinson Island South, Florida
Hutchinson Island South is a census-designated place on the barrier island of Hutchinson Island in St. Lucie County, Florida, United States. The South in its name refers to its location in the southern part of St. Lucie County. It is actually in the central or middle part of the island as a...
in particular is a major nesting area in Florida waters. Notable locations in South America include secluded beaches in Suriname
Suriname
Suriname , officially the Republic of Suriname , is a country in northern South America. It borders French Guiana to the east, Guyana to the west, Brazil to the south, and on the north by the Atlantic Ocean. Suriname was a former colony of the British and of the Dutch, and was previously known as...
and French Guiana
French Guiana
French Guiana is an overseas region of France, consisting of a single overseas department located on the northern Atlantic coast of South America. It has borders with two nations, Brazil to the east and south, and Suriname to the west...
. In the Southern Atlantic Ocean, the most notable nesting grounds for Chelonia mydas are found on the island of Ascension
Ascension Island
Ascension Island is an isolated volcanic island in the equatorial waters of the South Atlantic Ocean, around from the coast of Africa and from the coast of South America, which is roughly midway between the horn of South America and Africa...
, hosts 6-13,000 turtle nests.
In contrast with the sporadic distribution of nesting sites, feeding grounds are much more widely distributed throughout the region. Important feeding grounds in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
include Indian River Lagoon
Indian River Lagoon
The Indian River Lagoon is a grouping of three lagoons: Mosquito Lagoon, Banana River, and the Indian River, on the Atlantic Coast of Florida. It was originally named Rio de Ais after the Ais Indian tribe, who lived along the east coast of Florida....
, the Florida Keys
Florida Keys
The Florida Keys are a coral archipelago in southeast United States. They begin at the southeastern tip of the Florida peninsula, about south of Miami, and extend in a gentle arc south-southwest and then westward to Key West, the westernmost of the inhabited islands, and on to the uninhabited Dry...
, Florida Bay
Florida Bay
Florida Bay is the bay located between the southern end of the Florida mainland and the Florida Keys. Its area is variously stated to be , or , or . Nearly all of Florida Bay is included in Everglades National Park. The southern edge, along the Florida Keys is in the Florida Keys National Marine...
, Homosassa, Crystal River
Crystal River (Florida)
The Crystal River is a very short river in Citrus County, Florida flowing into the Gulf of Mexico. It is just seven miles long, and has a drainage basin of five square miles , joining Kings Bay to the Gulf of Mexico...
and Cedar Key.
Indo-Pacific subpopulation
In the PacificPacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, its range reaches as far north as the southern coast of Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
and as far south as Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
in the east. The turtle's distribution in the western Pacific reaches north to Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
and southern parts of Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
's Pacific coast, and as far south as the northern tip of New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
and a few islands south of Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
. The turtles can be found throughout the Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
.
Significant nesting grounds are scattered throughout the entire Pacific region, including Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
including O'ahu's Turtle Bay
Turtle Bay, O'ahu
Turtle Bay is located between Protection Point and Kuilima Point on the North Shore of the island of O'ahu in the U.S. state of Hawaii.-Geography and environment:...
, the South Pacific
Oceania
Oceania is a region centered on the islands of the tropical Pacific Ocean. Conceptions of what constitutes Oceania range from the coral atolls and volcanic islands of the South Pacific to the entire insular region between Asia and the Americas, including Australasia and the Malay Archipelago...
, the northern coast of Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
. Major Indian Ocean nesting colonies include India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, Pakistan
Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...
and other coastal countries. The east coast of the African continent
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
hosts a few nesting grounds, including islands in the waters around Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
.
Gulf of California
The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...
. Green turtles belonging to the distinct Hawaiian subpopulation nest at the protected French Frigate Shoals
French Frigate Shoals
The French Frigate Shoals is the largest atoll in the Northwestern Hawaiian Islands. Its name commemorates French explorer Jean-François de La Pérouse, who nearly lost two frigates when attempting to navigate the shoals...
some 800 kilometres (497.1 mi) west of the Hawaiian Islands. In the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
, green turtles nest in the Turtle Islands
Turtle Islands, Tawi-Tawi
Turtle Islands, also known as Turtle Isles, is a 5th class municipality composed of a remote group of seven islands in the province of Tawi-Tawi in the Southern Philippines.-Location:...
along with closely related hawksbill turtle
Hawksbill turtle
The hawksbill sea turtle is a critically endangered sea turtle belonging to the family Cheloniidae. It is the only extant species in its genus. The species has a worldwide distribution, with Atlantic and Pacific subspecies. E. imbricata imbricata is the Atlantic subspecies, while E...
s. Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
has a few nesting beaches, one in the Meru Betiri National Reserve in East Java
East Java
East Java is a province of Indonesia. It is located on the eastern part of the island of Java and includes neighboring Madura and islands to its east and to its north East Java is a province of Indonesia. It is located on the eastern part of the island of Java and includes neighboring Madura and...
. The Coral Sea has nesting areas of world significance. The Great Barrier Reef
Great Barrier Reef
The Great Barrier Reef is the world'slargest reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,600 kilometres over an area of approximately...
has two genetically distinct populations
Population genetics
Population genetics is the study of allele frequency distribution and change under the influence of the four main evolutionary processes: natural selection, genetic drift, mutation and gene flow. It also takes into account the factors of recombination, population subdivision and population...
; one north and one south. 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 is on Raine Island
Raine Island
Raine Island is a vegetated coral cay that is 32 hectares in total area and is situated on the outer edges of the Great Barrier Reef, approximately north north west of Cairns, Queensland, Australia, and about 120 km east-north-east of Cape Grenville, Cape York Peninsula...
.
Major nesting sites are common on either side of the Arabian Sea
Arabian Sea
The Arabian Sea is a region of the Indian Ocean bounded on the east by India, on the north by Pakistan and Iran, on the west by the Arabian Peninsula, on the south, approximately, by a line between Cape Guardafui in northeastern Somalia and Kanyakumari in India...
, both in Ash Sharqiyah
Ash Sharqiyah Region (Oman)
Ash Sharqiyah is the eastern region of the Sultanate of Oman. The capital of Ash Sharqiyah is Sur....
, Oman
Oman
Oman , officially called the Sultanate of Oman , is an Arab state in southwest Asia on the southeast coast of the Arabian Peninsula. It is bordered by the United Arab Emirates to the northwest, Saudi Arabia to the west, and Yemen to the southwest. The coast is formed by the Arabian Sea on the...
, and along the coast of Karachi
Karachi
Karachi is the largest city, main seaport and the main financial centre of Pakistan, as well as the capital of the province of Sindh. The city has an estimated population of 13 to 15 million, while the total metropolitan area has a population of over 18 million...
, Pakistan
Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...
. Some specific beaches there, such as Hawke's Bay
Hawke's Bay (Karachi)
Hawke's Bay Town is located in Keamari Town in Karachi, Sindh, Pakistan. Hawke's Bay Town was notified in July, 1984 by Karachi Development Authority. It is a residential Scheme for low / medium income group....
and Sandspit
Sandspit Beach
Sandspit Beach is situated south west of Karachi, Sindh, Pakistan. It is a very famous tourist spot. The sea at Sandspit is very calm and quiet from October to March and very rough during the monsoon. Remarkable variety of marine life-algae, and crabs are found here. The shallow water here is ideal...
, are common to both C. mydas and L. olivacea
Olive Ridley
The olive ridley sea turtle , also known as the Pacific ridley, is a species of sea turtle.- Description :The olive ridley is a small extant sea turtle, with an adult carapace length averaging 60 to 70 cm 1...
subpopulation. Sandy beaches along Sindh
Sindh
Sindh historically referred to as Ba'ab-ul-Islam , is one of the four provinces of Pakistan and historically is home to the Sindhi people. It is also locally known as the "Mehran". Though Muslims form the largest religious group in Sindh, a good number of Christians, Zoroastrians and Hindus can...
and Balochistan
Balochistan (Pakistan)
Balochistan is one of the four provinces or federating units of Pakistan. With an area of 134,051 mi2 or , it is the largest province of Pakistan, constituting approximately 44% of the total land mass of Pakistan. According to the 1998 population census, Balochistan had a population of...
are nesting sites. Some 25 kilometres (15.5 mi) off the Pakistani coast
Geography of Pakistan
The geography of Pakistan is a profound blend of landscapes varying from plains to deserts, forests, hills, and plateaus ranging from the coastal areas of the Arabian Sea in the south to the mountains of the Karakoram range in the north...
, Astola island
Astola
Astola Island, also known as Jezira Haft Talar ) or 'island of the seven hills' or satadip, is a small, uninhabited island in the Arabian Sea, in the territorial waters of Pakistan, some 25 km south of Pakistan's nearest coastline and 39 km southeast of the Pakistani fishing port of Pasni...
is another nesting beach.
On December 30, 2007, fishermen, using a hulbot-hulbot (a type of fishnet) accidentally caught an 80 kilograms (176.4 lb), 93 centimetres (36.6 in) and 82 centimetres (32.3 in) wide, turtle off Barangay Bolong, Zamboanga City
Zamboanga City
The City of Zamboanga : is a highly urbanized, independent and a chartered city located in Mindanao, Philippines....
, Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
. December is breeding season near the Bolong beach.
Ecology and behavior
As one of the first sea turtle species studied, much of what is known of sea turtle ecology comes from studies of green turtles. The ecology of C. mydas changes drastically with each stage of its life history. Newly emerged hatchlings are carnivorous, pelagic organisms, part of the open ocean mininektonNekton
Nekton refers to the aggregate of actively swimming aquatic organisms in a body of water able to move independently of water currents....
. In contrast, immature juveniles and adults are commonly found in seagrass meadows closer inshore as herbivorous grazers.
Habitat
Green sea turtles move across three habitatHabitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
types, depending on their life stage
Biological life cycle
A life cycle is a period involving all different generations of a species succeeding each other through means of reproduction, whether through asexual reproduction or sexual reproduction...
. They lay eggs on beaches. Mature turtles spend most of their time in shallow, coastal waters with lush seagrass beds. Adults frequent inshore bays, lagoons and shoals with lush seagrass meadows. Entire generations often migrate between one pair of feeding and nesting areas.
Turtles spend most of their first five years in convergence zones within the open ocean. These young turtles are rarely seen as they swim in deep, pelagic waters.
Green sea turtles typically swim at 2.5-3kph (0.7-0.8 m/s).
Predators
Only human beings and the larger sharkShark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s feed on C. mydas adults. Specifically, tiger shark
Tiger shark
The tiger sharks, Galeocerdo cuvier, is a species of requiem shark and the only member of the genus Galeocerdo. Commonly known as sea tigers, tiger sharks are relatively large macropredators, capable of attaining a length of over . It is found in many tropical and temperate waters, and is...
s (Galeocerdo cuvier) hunt adults in Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
an waters. Juveniles and new hatchlings have significantly more predators, including crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s, small marine mammal
Marine mammal
Marine mammals, which include seals, whales, dolphins, and walruses, form a diverse group of 128 species that rely on the ocean for their existence. They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding. The level of...
s and shorebirds. In Turkey, their eggs are vulnerable to predation by red fox
Red Fox
The red fox is the largest of the true foxes, as well as being the most geographically spread member of the Carnivora, being distributed across the entire northern hemisphere from the Arctic Circle to North Africa, Central America, and the steppes of Asia...
es and golden jackal
Golden Jackal
The golden jackal , also known as the common jackal, Asiatic jackal, thos or gold-wolf is a Canid of the genus Canis indigenous to north and northeastern Africa, southeastern and central Europe , Asia Minor, the Middle East and southeast Asia...
s.
Life cycle
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
, mating season is from June to September. The French Guiana
French Guiana
French Guiana is an overseas region of France, consisting of a single overseas department located on the northern Atlantic coast of South America. It has borders with two nations, Brazil to the east and south, and Suriname to the west...
nesting subpopulation nests from March to June. In the tropics, green turtles nest throughout the year, although some subpopulations prefer particular times of the year. In Pakistan
Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...
, Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
turtles nest year-round, but prefer the months of July to December.
Green sea turtles mating is similar to other marine turtles. Female turtles control the process. A few populations practice polyandry
Polyandry
Polyandry refers to a form of marriage in which a woman has two or more husbands at the same time. The form of polyandry in which a woman is married to two or more brothers is known as "fraternal polyandry", and it is believed by many anthropologists to be the most frequently encountered...
, although this does not seem to benefit hatchlings. After mating in the water, the female moves above the beach's high tide line, where she digs a hole with her hind flippers and deposits her eggs. Clutch size depends on the age of the female and species, but can range between 100 and 200. She then covers the nest with sand and returns to the sea.
At around 45 to 75 days, the eggs hatch during the night, and the hatchlings instinct
Instinct
Instinct or innate behavior is the inherent inclination of a living organism toward a particular behavior.The simplest example of an instinctive behavior is a fixed action pattern, in which a very short to medium length sequence of actions, without variation, are carried out in response to a...
ively head directly into the water. This is the most dangerous time in a turtle's life. As they walk, predators, such as gull
Gull
Gulls are birds in the family Laridae. They are most closely related to the terns and only distantly related to auks, skimmers, and more distantly to the waders...
s and crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s, feed on them. A significant percentage never make it to the ocean. Little is known of the initial life history of newly hatched sea turtles. Juveniles spend three to five years in the open ocean before they settle as still-immature juveniles into their permanent shallow-water lifestyle. It is speculated that they take twenty to fifty years to reach sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
. Individuals live up to eighty years in the wild.
Each year on Ascension Island
Ascension Island
Ascension Island is an isolated volcanic island in the equatorial waters of the South Atlantic Ocean, around from the coast of Africa and from the coast of South America, which is roughly midway between the horn of South America and Africa...
in the South Atlantic, C. mydas females create 6,000 to 15,000 nests. They are among the largest green turtles in the world; many are more than a meter in length and weigh up to 300 kilograms (661.4 lb).
Breathing and sleep
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 permit a rapid exchange of oxygen and prevent gases from being trapped during deep dives. Sea turtle blood can deliver oxygen efficiently to body tissues even at the pressures encountered during diving. During routine activity, green and loggerhead turtles dive for about four to five minutes, and surface to breathe for one to three 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 quickly drown in shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
trawlers and other fishing gear.
Importance to humans
Tanning
Tanning is the making of leather from the skins of animals which does not easily decompose. Traditionally, tanning used tannin, an acidic chemical compound from which the tanning process draws its name . Coloring may occur during tanning...
and used to make handbag
Handbag
A handbag, or purse in American English, is a handled medium-to-large bag that is often fashionably designed, typically used by women, to hold personal items such as wallet/coins, keys, cosmetics, a hairbrush, pepper spray, cigarettes, mobile phone etc....
s, especially in Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
. Ancient Chinese considered the flesh of sea turtles a culinary delicacy, including and especially C. mydas. Particularly for this species, the turtle's calipee, fat and cartilage
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
are sought as ingredients for making turtle soup
Turtle soup
Turtle soup is soup or stews made from the flesh of the turtle. The dish exists in many cultures and is viewed as a luxury or delicacy.The green turtle was commonly used for turtle soup in the United States and United Kingdom. Soup made from the snapping turtle was found mainly in the United States...
.
In Java
Java
Java is an island of Indonesia. With a population of 135 million , it is the world's most populous island, and one of the most densely populated regions in the world. It is home to 60% of Indonesia's population. The Indonesian capital city, Jakarta, is in west Java...
, Indonesia
Indonesia
Indonesia , officially the Republic of Indonesia , is a country in Southeast Asia and Oceania. Indonesia is an archipelago comprising approximately 13,000 islands. It has 33 provinces with over 238 million people, and is the world's fourth most populous country. Indonesia is a republic, with an...
, sea turtle eggs were a popular delicacy. However, the turtle's flesh is regarded as ḥarām
Haram
The Arabic term has a meaning of "sanctuary" or "holy site" in Islam.-Etymology:The Arabic language has two separate words, and , both derived from the same triliteral Semitic root . Both of these words can mean "forbidden" and/or "sacred" in a general way, but each has also developed some...
or "unclean" under Islamic law
Sharia
Sharia law, is the moral code and religious law of Islam. Sharia is derived from two primary sources of Islamic law: the precepts set forth in the Quran, and the example set by the Islamic prophet Muhammad in the Sunnah. Fiqh jurisprudence interprets and extends the application of sharia to...
(Islam
Islam
Islam . The most common are and . : Arabic pronunciation varies regionally. The first vowel ranges from ~~. The second vowel ranges from ~~~...
is Java's primary religion). In Bali
Bali
Bali is an Indonesian island located in the westernmost end of the Lesser Sunda Islands, lying between Java to the west and Lombok to the east...
, turtle meat was a prominent feature at ceremonial and religious feasts. Turtles were harvested in the remotest parts of the Indonesian archipelago. Bali has been importing sea turtles since the 1950s, as its own turtle supplies became depleted. The mostly Hindu Balinese
Balinese people
The Balinese population of 3.0 million live mostly on the island of Bali, making up 89% of the island's population. There are also significant populations on the island of Lombok, and in the eastern-most regions of Java The Balinese population of 3.0 million (1.5% of Indonesia's population) live...
do not eat the eggs, but sell them instead to local Muslim
Muslim
A Muslim, also spelled Moslem, is an adherent of Islam, a monotheistic, Abrahamic religion based on the Quran, which Muslims consider the verbatim word of God as revealed to prophet Muhammad. "Muslim" is the Arabic term for "submitter" .Muslims believe that God is one and incomparable...
s.
Commercial farms, such as the Cayman Turtle Farm in the West Indies, once bred them for commercial sale from eggs removed from nests below the waterline. The farms held as many as 100,000 turtles at any one time. When the markets were closed by regulations that did not allow even farm-bred turtles to be sold, the surviving farms became tourist attractions, supporting 11,000 turtles.
Conservation
Threats
Human action presents both intentional and unintentional threats to the species' survival. Intentional threats include continued huntingTurtling (hunting)
Turtling is the hunting of turtles, a practice formerly a big part of the economy in many nations of the West Indies. In recent times, however, it has become outlawed....
and egg harvesting. More dangerous are unintentional threats, including boat strikes, fishermen's nets that lack turtle excluder device
Turtle excluder device
A turtle excluder device or TED is a specialized device that allows a captured sea turtle to escape when caught in a fisherman's net.In particular, sea turtles can be caught when bottom trawling is used by the commercial shrimp fishing industry. In order to catch shrimp, a fine meshed trawl net is...
s, pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
and habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
. Chemical pollution may create tumor
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
s; effluent
Effluent
Effluent is an outflowing of water or gas from a natural body of water, or from a human-made structure.Effluent is defined by the United States Environmental Protection Agency as “wastewater - treated or untreated - that flows out of a treatment plant, sewer, or industrial outfall. Generally refers...
from harbor
Harbor
A harbor or harbour , or haven, is a place where ships, boats, and barges can seek shelter from stormy weather, or else are stored for future use. Harbors can be natural or artificial...
s near nesting sites may create disturbances; and light pollution
Light pollution
Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light.The International Dark-Sky Association defines light pollution as:...
may disorient hatchlings. Habitat loss usually occurs due to human development of nesting areas. Beach-front construction, land "reclamation" and increased tourism are examples of such development. An infectious tumor
Tumor
A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
-causing disease, fibropapillomatosis
Fibropapillomatosis
Fibropapillomatosis is a condition characterized by the presence of fibropapillomas, neoplasms consisting of both the epidermal and dermal skin layers.-In sea turtles:...
, is also a problem in some populations. The disease kills a sizeable fraction of those it infects, though some individuals seem to resist the disease. Because of these threats, many populations are in a vulnerable state.
Pacific green turtle’s foraging habitats are poorly understood and mostly unknown. These foraging grounds are most likely along the coast of Baja California, Mexico and southern California, in which these turtle’s have a high risk of incidental capture by coastal fisheries. The main mortality factor for these turtles is the shrimp trawlers in Mexico, in which many of these turtles go undocumented. The only foraging area that has been identified is the San Diego Bay, but it is heavily polluted with metals and PCBs. These contaminants have a negative effect on the ocean environment, and have been shown to cause lesions and sometimes mortality. Green turtles also are threatened by entanglement and ingestion of plastic. In San Diego Bay, an adult green turtle was found dead with monofilament netting tightly packed in its esophagus.
Global initiatives
The International Union for the Conservation of Nature (IUCN) has repeatedly listed green sea turtles in its Red List under differing criteria. In 1982, they officially classified it as an endangered speciesEndangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
. The 1986, 1988, 1990, 1994, and the landmark 1996 edition of the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
, retained the listing.
In 2001, Nicholas Mrosovsky filed a delisting petition, claiming some green turtle populations were large, stable and in some cases, increasing. At the time, the species was listed under the strict EN A1abd criteria. The IUCN Standards and Petitions Subcommittee ruled that visual counts of nesting females could not be considered "direct observation" and thus downgraded the species' status to EN A1bd—retaining the turtle's endangered status.
In 2004, the IUCN reclassified C. mydas as endangered under the EN A2bd criteria, which essentially states the wild populations face a high risk of extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
because of several factors. These factors include a probable population reduction of more than 50% over the past decade as estimated from abundance indices and by projecting exploitation levels.
On May 3, 2007, C. mydas was listed on Appendix I of the Convention on International Trade in Endangered Species (CITES) as a member of the family Cheloniidae
Cheloniidae
Cheloniidae is a family of turtles belonging to the sea turtle superfamily Chelonioidea.-Extant genera:*Genus Caretta**Loggerhead sea turtle *Genus Chelonia**Green sea turtle *Genus Eretmochelys...
. The species was originally listed on Appendix II in 1975. The entire family was moved to Appendix I in 1977, with the exception of the Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n population of C. mydas. In 1981, the Australian population joined the rest. It is therefore illegal to import, export, kill, capture or harass green turtles.
The Mediterranean population is listed as critically endangered. The eastern Pacific, Hawaiian and Southern California subpopulations are designated threatened. Specific Mexican subpopulations are listed as endangered. The Florida population is listed as endangered. The World Wide Fund for Nature
World Wide Fund for Nature
The World Wide Fund for Nature is an international non-governmental organization working on issues regarding the conservation, research and restoration of the environment, formerly named the World Wildlife Fund, which remains its official name in Canada and the United States...
has labeled populations in Pakistan as "rare and declining".
Country-specific initiatives
The traditional uses of turtle on Bali were once deemed sustainable, but have been questioned considering greater demand from the larger and wealthier human population. The harvest was the most intensive in the world. In 1999, Indonesia restricted turtle trade and consumption because of the decreasing population and threat of a tourist boycott. It rejected a request made by Bali Governor I Made Mangku Pastika
I Made Mangku Pastika
Colonel General Police I Made Mangku Pastika is the governor of Bali for the 2008-2013 term. Pastika was a former Chief Balinese Police Region and former chief of Indonesia's National Narcotics Board....
in November 2009 to set a quota of 1,000 turtles to be killed in Hindu
Hindu
Hindu refers to an identity associated with the philosophical, religious and cultural systems that are indigenous to the Indian subcontinent. As used in the Constitution of India, the word "Hindu" is also attributed to all persons professing any Indian religion...
religious ceremonies. While conservationists respect the need for turtles in rituals, they wanted a smaller quota.
Ecotourism
Ecotourism
Ecotourism is a form of tourism visiting fragile, pristine, and usually protected areas, intended as a low impact and often small scale alternative to standard commercial tourism...
is one initiative in Sabah
Sabah
Sabah is one of 13 member states of Malaysia. It is located on the northern portion of the island of Borneo. It is the second largest state in the country after Sarawak, which it borders on its southwest. It also shares a border with the province of East Kalimantan of Indonesia in the south...
, Malaysia. The island of Pulau Selingan is home to a turtle hatchery
Hatchery
A hatchery is a facility where eggs are hatched under artificial conditions, especially those of fish or poultry. It may be used for ex-situ conservation purposes, i.e. to breed rare or endangered species under controlled conditions; alternatively, it may be for economic reasons A hatchery is a...
. Staff people place some of the eggs laid each night in a hatchery to protect them from predators. Incubation takes around sixty days. When the eggs hatch, tourists assist in the release of the baby turtles into the sea.
In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, the U.S. Fish and Wildlife Services and National Marine Fisheries Service
National Marine Fisheries Service
The National Marine Fisheries Service is a United States federal agency. A division of the National Oceanic and Atmospheric Administration and the Department of Commerce, NMFS is responsible for the stewardship and management of the nation's living marine resources and their habitat within the...
classify C. mydas as a threatened species under the Endangered Species Act, rendering it a federal offense to capture or kill an individual turtle. The Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
an subpopulation has made a remarkable comeback and is now one focus of ecotourism and has become something of a state mascot
Mascot
The term mascot – defined as a term for any person, animal, or object thought to bring luck – colloquially includes anything used to represent a group with a common public identity, such as a school, professional sports team, society, military unit, or brand name...
. Students of Hawaii Preparatory Academy
Hawaii Preparatory Academy
Hawaii Preparatory Academy is a coeducational, boarding, independent school in Kamuela, Hawaii teaching kindergarten through the twelfth grade. Founded in 1949 by The Right Reverend Harry S. Kennedy, Episcopal Bishop of Honolulu, the school came of age under the leadership of James Monroe Taylor...
Ascension Island
Ascension Island
Ascension Island is an isolated volcanic island in the equatorial waters of the South Atlantic Ocean, around from the coast of Africa and from the coast of South America, which is roughly midway between the horn of South America and Africa...
in the South Atlanticon the Big Island
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
have tagged thousands of specimens since the early 1990s.
In the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
the species is protected by a Biodiversity Action Plan
Biodiversity Action Plan
A Biodiversity Action Plan is an internationally recognized program addressing threatened species and habitats and is designed to protect and restore biological systems. The original impetus for these plans derives from the 1992 Convention on Biological Diversity...
, due to excess harvesting and marine pollution
Marine pollution
Marine pollution occurs when harmful, or potentially harmful effects, can result from the entry into the ocean of chemicals, particles, industrial, agricultural and residential waste, noise, or the spread of invasive organisms. Most sources of marine pollution are land based...
. The Pakistani-branch of the World Wide Fund for Nature
World Wide Fund for Nature
The World Wide Fund for Nature is an international non-governmental organization working on issues regarding the conservation, research and restoration of the environment, formerly named the World Wildlife Fund, which remains its official name in Canada and the United States...
has been initiating projects for secure turtle hatching since the 1980s. However, the population has continued to decline.
In the Atlantic, conservation initiatives have centered around Caribbean nesting sites. The Tortuguero nesting beaches in Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
have been the subject of egg-collection limits since the 1950s. The Tortuguero National Park
Tortuguero National Park
Tortuguero National Park is a National Park within the Tortuguero Conservation Area. The reserve is also included in the Humedal Caribe Noreste, a wetland of international importance under the Ramsar Convention. The park is located in the Limón Province of northeastern Costa Rica...
was formally established in 1976, in part, to protect that region's nesting grounds. On Ascension Island
Ascension Island
Ascension Island is an isolated volcanic island in the equatorial waters of the South Atlantic Ocean, around from the coast of Africa and from the coast of South America, which is roughly midway between the horn of South America and Africa...
, which contains some of the most important nesting beaches, an active conservation program has been implemented., Karumbé has been monitoring foraging and developmental areas of juvenile green turtles in Uruguay since 1999.
See also
- Galápagos Green TurtleGalápagos Green TurtleThe Galápagos green turtle is a subspecies of the green sea turtle . It is endemic to the tropical and subtropical waters of the Pacific Ocean. They are often categorized as one population of the east Pacific green turtle. This title is shared with the other green sea turtle nesting populations...
- a subspecies of the green sea turtle - Chelonioidea - the sea turtleSea turtleSea turtles are marine reptiles that inhabit all of the world's oceans except the Arctic.-Distribution:...
superfamily. - Sea Turtle Association of Japan, Kuroshima Research StationSea Turtle Association of Japan, Kuroshima Research StationKuroshima Research Station started in 1973, under the name of the UnderwaterPark Foundation, Yaeyama Underwater Park Research Institute, for the purpose of managing and utilizing the underwater area in Sekisei lagoon between Ishigaki Island and Iriomote Island including Kuroshima Island...
External links
- Images and movies (Chelonia mydas)—ARKive
- US National Marine Fisheries Service green sea turtle page
- Floridian and Mexican populations—US Fish and Wildlife Service
- IUCN Red List entry
- Desktop wallpaper & fun green turtle facts
- Green Turtle video - Macaulay Library