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The green sea turtle (''Chelonia mydas''), also known as the green turtle, black (sea) turtle or Pacific green turtle, is a
species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individu ...

species
of large
sea turtle Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines Turtles are reptile Reptiles are tetrapod Tetrapods (; from Greek 'four' and 'foot') are four-limbed animals constitut ...

sea turtle
of the
family In human society A society is a Social group, group of individuals involved in persistent Social relation, social interaction, or a large social group sharing the same spatial or social territory, typically subject to the same Politic ...
Cheloniidae Cheloniidae is a family of typically large marine turtles that are characterised by their common traits such as, having a flat streamlined wide and rounded shell and almost paddle-like flippers for their forelimbs. The six species that make up thi ...
. It is the only
species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individu ...

species
in the
genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), circumscribing) and classifying gr ...
''Chelonia''. Its range extends throughout
tropical The tropics are the region of Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. The remaining 70.8% ...

tropical
and
subtropical The subtropical zones or subtropics are geographical Geography (from Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country locat ...

subtropical
seas around the world, with two distinct populations in the
Atlantic
Atlantic
and
Pacific Ocean The Pacific Ocean is the largest and deepest of Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. ...

Pacific Ocean
s, but it is also found in the
Indian Ocean The Indian Ocean is the third-largest of the world's five ocean The ocean (also the or the world ocean) is the body of that covers approximately 70.8% of the surface of and contains 97% of . Another definition is "any of the large ...

Indian Ocean
. The common name refers to the usually green
fat In nutrition Nutrition is the biochemical Biochemistry or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided ...

fat
found beneath its
carapace A carapace is a Dorsum (biology), dorsal (upper) 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 tor ...
, not to the color of its carapace, which is olive to black. The
dorsoventrally Standard anatomical terms of location deal unambiguously with the anatomy of animals, including humans. Terms used generally derive from Latin or Greek language, Greek roots and used to describe something in its standard anatomical position. This ...
flattened body of ''C. mydas'' is covered by a large, teardrop-shaped carapace; it has a pair of large,
paddle *When used for paddling Paddling with regard to watercraft is the act of manually propelling a boat using a paddle. The paddle, which consists of one or two blades joined to a shaft, is also used to steer the vessel. The paddle is not connec ...

paddle
-like
flippers Flipper may refer to: Common meanings *Flipper (anatomy), a forelimb of an aquatic animal, useful for steering and/or propulsion in water *Alternate name for a swimfin, footwear that boosts human swimming efficiency *Flipper (pinball), a part of a ...
. It is usually lightly colored, although in the eastern Pacific populations, parts of the carapace can be almost black. Unlike other members of its family, such as the
hawksbill sea turtle The hawksbill sea turtle (''Eretmochelys imbricata'') is a critically endangered sea turtle Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines and of the suborder Cryptodira. The seven ...

hawksbill sea turtle
, ''C. mydas'' is mostly
herbivorous A herbivore is an animal Animals (also called Metazoa) are multicellular A multicellular organism is an organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All ...
. The adults usually inhabit shallow
lagoon A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' and ''atoll lagoons''. They ...

lagoon
s, feeding mostly on various species of
seagrass Seagrasses are the only flowering plant Flowering plants include multiple members of the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek#REDIRECT Greek Greek may refer to: Greece Anyt ...

seagrass
es. The turtles bite off the tips of the blades of seagrass, which keeps the grass healthy. Like other sea turtles, green sea turtles
migrate Migration, migratory, or migrate may refer to: Human migration * Human migration, physical movement by humans from one region to another ** International migration, when peoples cross state boundaries and stay in the host state for some minimum len ...
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 scramble into the water. Those that reach maturity may live to 90 years in the wild. ''C. mydas'' is listed as
endangered An endangered species is a species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group ...
by the
IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization An international organization (also known as an international institut ...
and
CITES CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty A multilateral treaty is a treaty A treaty is a formal, leg ...

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 due to human activity. In some countries, turtles and their eggs are still hunted for food.
Pollution Pollution is the introduction of contaminant Contamination is the presence of a constituent, impurity, or some other undesirable element that spoils, corrupts, infects, makes unfit, or makes inferior a material, physical body, natural en ...

Pollution
indirectly harms turtles at both population and individual scales. Many turtles die after being
caught Caught is a method of dismissing a batsman In cricket Cricket is a Bat-and-ball games, bat-and-ball game played between two teams of eleven players each on a cricket field, field at the centre of which is a cricket pitch, pitch with ...
in fishing nets. In addition, real estate
development Development or developing may refer to: Arts *Development hell Development hell, development purgatory, development limbo, or production hell, is a media Media may refer to: Physical means Communication * Media (communication), tool ...
often causes
habitat loss Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat In ecology Ecology (from el, οἶκος, "house" and el, -λογία, label=none, "study of") is the study of the rela ...
by eliminating nesting beaches.


Taxonomy

The green sea turtle is a member of the
tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant usage of the term is in the discipline of anthropology. The definition is contested, in part due to conflicting theoretical understa ...
Chelonini. A 1993 study clarified the status of
genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), circumscribing) and classifying gr ...
''Chelonia'' with respect to the other marine turtles. The
carnivorous A carnivore , meaning "meat eater" (Latin, ''caro'', genitive ''carnis'', meaning "meat" or "flesh" and ''vorare'' meaning "to devour"), is an organism, animal whose food and energy requirements derive solely from animal Tissue (biology), tissu ...
'' Eretmochelys'' (hawksbill), ''
Caretta The loggerhead sea turtle (''Caretta caretta''), is a species of sea turtle, oceanic turtle distributed throughout the world. It is a marine reptile, belonging to the Family (biology), family Cheloniidae. The average loggerhead measures around ...

Caretta
'' (loggerhead) and '' Lepidochelys'' (ridley) were assigned to the tribe Carettini.
Herbivorous A herbivore is an animal Animals (also called Metazoa) are multicellular A multicellular organism is an organism In biology, an organism () is any organic, life, living system that functions as an individual entity. All ...

Herbivorous
''Chelonia'' warranted their status as a
genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank In biological classification In biology, taxonomy () is the scientific study of naming, defining (Circumscription (taxonomy), circumscribing) and classifying gr ...
, while '' Natator'' (flatback) was further removed from the other genera than previously believed. The species was originally described by
Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement Ennoblement is the conferring of nobility—the induction of an individual into the noble social class, class. Currently only a few kingdoms still grant nob ...

Carl Linnaeus
in his landmark 1758 10th edition of ''Systema Naturae'' as ''Testudo mydas''. In 1868,
Marie Firmin Bocourt Marie Firmin Bocourt (19 April 1819 – 4 February 1904) was a French zoologist Zoology ()The pronunciation of zoology as is typically regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom ...
named a particular species of sea turtle ''Chelonia agassizii'', in honor of Swiss-American zoologist
Louis Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he rece ...

Louis Agassiz
. This "species" was referred to as the "black sea turtle". Later research determined Bocourt's "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 populations were given subspecies status: ''C. mydas mydas'' referred to the originally described population, while '''' referred only to the Pacific population known as the Galápagos green turtle. 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 The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. In botanical nomenclature Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy Taxonomy ...
of ''C. mydas''. The species'
common name Common may refer to: Places * Common, a townland in County Tyrone, Northern Ireland * Boston Common Boston Common (also known as the Common) is a central public park in downtown Boston, Massachusetts. It is sometimes erroneously referred to as ...
does not derive from any particular
green Green is the color between blue and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 Nanometre, nm. In subtractive color systems, used in painting and color printing, it is created by ...

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 has many local names. In the
Hawaiian language Hawaiian (', ) is a Polynesian language The Polynesian languages form a language family A language is a structured system of communication used by humans, including speech ( spoken language), gestures (Signed language, sign language) and ...
it is called ''honu'', and it is locally known as a symbol of good luck and longevity. File:Green Sea Turtle, Curaçao.jpg, Green sea turtle swimming over the sand plateau at playa Grandi,
Curaçao Curaçao ( ; ; pap, Kòrsou, ) is a Lesser Antilles The Lesser Antilles ( es, link=no, Antillas Menores; french: link=no, Petites Antilles; pap, Antias Menor; nl, Kleine Antillen) are a group of islands in the Caribbean Sea The Cari ...
File:Female Green Sea Turtle.jpg, Female returning to the sea after nesting in
Redang Island Redang Island ( ms, Pulau Redang) is an island in Kuala Nerus District, Terengganu, Malaysia. It is one of the largest islands off the east coast of Peninsular Malaysia. It is famous for its crystal clear waters and white sandy beaches. It is one o ...
,
Malaysia Malaysia ( ; ) is a country in Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia or SEA, is the geographical southeastern subregion of Asia, consisting of the regions ...

Malaysia
File:Young Honu-Kahala.png, alt=Photo of two swimming turtles, Immature
Hawaii Hawaii ( ; haw, Hawaii or ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspape ...

Hawaii
an ''C. mydas'' File:Karettschildkroete 01.jpg, alt=Photo of swimming turtle at twilight, Swimming in a
Mexican Mexican may refer to: Mexico and its culture *Being related to, from, or connected to the country of Mexico, in North America ** Being related to the State of Mexico, one of the 32 federal entities of Mexico ** Culture of Mexico *** Mexican cuisi ...

Mexican
coral reef File:Green Sea Turtles, Chelonia mydas is getting back to the ocean leaving a track.jpg, alt=Photo of turtle walking on beach, Heading for the ocean on a beach at the Pu'uhonua o Honaunau National Historical Park File:Green sea turtle near Marsa Alam.JPG, Green sea turtle near
Marsa Alam Marsa Alam ( ar, مرسى علم ', ) is a town in south-eastern Egypt Egypt ( ar, مِصر, Miṣr), officially the Arab Republic of Egypt, is a spanning the and the of . It is bordered by the to , the () and to , the to the east, ...
,
Egypt Egypt ( ar, مِصر, Miṣr), officially the Arab Republic of Egypt, is a transcontinental country This is a list of countries located on more than one continent A continent is one of several large landmasses. Generally identi ...

Egypt
File:Green sea turtle portrait.JPG, Green sea turtle near
Marsa Alam Marsa Alam ( ar, مرسى علم ', ) is a town in south-eastern Egypt Egypt ( ar, مِصر, Miṣr), officially the Arab Republic of Egypt, is a spanning the and the of . It is bordered by the to , the () and to , the to the east, ...
,
Egypt Egypt ( ar, مِصر, Miṣr), officially the Arab Republic of Egypt, is a transcontinental country This is a list of countries located on more than one continent A continent is one of several large landmasses. Generally identi ...

Egypt
File:Total internal reflection of Chelonia mydas .jpg, Green sea turtle File:Green Turtle taking a breath.jpg, Coming up for a breath File:Green Sea Turtle, Maui.jpg, A green sea turtle at
Maui The island An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atoll An atoll (), sometimes known as ...

Maui


Description

Its appearance is that of a typical
sea turtle Sea turtles (superfamily Chelonioidea), sometimes called marine turtles, are reptiles of the order Testudines Turtles are reptile Reptiles are tetrapod Tetrapods (; from Greek 'four' and 'foot') are four-limbed animals constitut ...

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 long. The average weight of mature individuals is and the average carapace length is . Exceptional specimens can weigh or even more, with the largest known ''C. mydas'' having weighed and measured in carapace length. Anatomically, a few characteristics distinguish the green turtle from the other members of its family. Unlike its close relative the
hawksbill turtle The hawksbill sea turtle (''Eretmochelys imbricata'') is a critically endangered sea turtle belonging to the family Cheloniidae. It is the only extant species in the genus ''Eretmochelys''. The species has a worldwide distribution, with Atlantic ...

hawksbill turtle
, the green turtle's snout is very short and its
beak The beak, bill, and/or rostrum is an external anatomical structure found mostly in birds Birds are a group of warm-blooded vertebrate Vertebrates () comprise all species of animal Animals (also called Metazoa) are multicellu ...

beak
is unhooked. The neck cannot be pulled into the shell. 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 A scute or scutum (Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the ...
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 The turtle shell is a shield for the ventral and dorsal parts of turtles (the Order (biology), order Testudines), completely enclosing all the vital organs of the turtle and in some cases even the head. It is constructed of modified bony elements ...

plastron
and its shell. Mature ''C. mydas'' front appendages have only a single claw (as opposed to the hawksbill two), although a second claw is sometimes prominent in young specimens. The
carapace A carapace is a Dorsum (biology), dorsal (upper) 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 tor ...
of the turtle has various color patterns that change over time. Hatchlings of ''Chelonia 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
range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...
of the green sea turtle extends throughout
tropical The tropics are the region of Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. The remaining 70.8% ...

tropical
and
subtropical The subtropical zones or subtropics are geographical Geography (from Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country locat ...

subtropical
oceans worldwide. The two major
subpopulation In statistics Statistics is the discipline that concerns the collection, organization, analysis, interpretation, and presentation of data. In applying statistics to a scientific, industrial, or social problem, it is conventional to begin with ...
s are the Atlantic and the eastern Pacific subpopulations. Each population is genetically distinct, with its own set of nesting and feeding grounds within the population's known range. One of the genetic differences between the two subpopulations is the type of mitochondrial DNA found in individual's cells. Individuals from rookeries in the Atlantic Ocean and Mediterranean Sea have a similar type of mitochondrial DNA, and individuals from the Pacific and Indian Oceans have another type of mitochondrial DNA. Their native range includes tropical to subtropical waters along continental coasts and islands between 30°N and 30°S. Since green sea turtles are a migrating species, their global distribution spans into the open ocean. The differences in mitochondrial DNA more than likely stems from the populations being isolated from each other by the southern tips of both South America and Africa with no warm waters for the green sea turtles to migrate through. The green sea turtle is estimated to inhabit coastal areas of more than 140 countries, with nesting sites in over 80 countries worldwide throughout the year. In the United States Atlantic coast, green sea turtles can be found from Texas and north to Massachusetts. In the United States Pacific coast, they have been found from southern California north to the southernmost tip of Alaska. The largest populations of green sea turtles within the United States coastline are in the Hawaiian Islands and Florida. Globally, the largest populations of sea turtles are in the
Great Barrier Reef The Great Barrier Reef is the world's largest coral reef A coral reef is an underwater ecosystems, ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held tog ...

Great Barrier Reef
in Australia, and the Caribbean Sea.


Atlantic subpopulation

The green sea turtle can generally be found throughout the . Although the species is most abundant in tropical climates, green sea turtles can also be found in
temperate climate In geography Geography (from Ancient Greek, Greek: , ''geographia'', literally "earth description") is a field of science devoted to the study of the lands, features, inhabitants, and phenomena of the Earth and Solar System, plan ...
s, and individuals have been spotted as far north as
Canada Canada is a country in the northern part of North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, ...

Canada
in the western Atlantic, and the
British Isles The British Isles are a group of islands in the North Atlantic off the north-western coast of continental Europe Continental Europe or mainland Europe is the contiguous continent A continent is any of several large landmasse ...

British Isles
in the east. The subpopulation's southern range is known until past the southern tip of Africa in the east and
Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country located mostly in the southern half of South America South America is a continent A continent is any of several large landmasse ...

Argentina
in the western Atlantic. The major nesting sites can be found on various islands in the
Caribbean The Caribbean (, ; es, Caribe; french: Caraïbes; ht, Karayib; also gcf, label=Antillean Creole Antillean Creole (Antillean French Creole, Kreyol, Kwéyòl, Patois) is a French-based creole, which is primarily spoken in the Lesser Antilles ...
, along the eastern shores of the continental United States, the eastern coast of the 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 The United States Virgin Islands, officially the Virgin Islands of the United States, are a group of Caribbean The Caribbean (, ; es, Caribe; french: Caraïbes; ht, Karayib; also gcf, label=Antillean Creole Antillean Creole (Antillean ...
,
Puerto Rico Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico) is a Caribbean island and Unincorporated ...

Puerto Rico
, the
Dominican Republic The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares with ...

Dominican Republic
, and
Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in Central America Central America ( es, América Central, , ''Centroamérica'' ) is a region of the Amer ...

Costa Rica
. In recent years, there are signs of increased nesting in the Cayman Islands. 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 Georgia usually refers to: * Georgia (country) Georgia (, ; ) is a country located at the intersection of Eastern Europe and Western Asia. It is a part of the Caucasus region, bounded to the west by the Black Sea, to the north and east by ...
,
North Carolina North Carolina () is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily news ...

North Carolina
,
South Carolina South Carolina () is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspaper), a daily newspap ...

South Carolina
, and all along the east coast of
Florida Florida is a U.S. state, state located in the Southeastern United States, Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia (U.S. state), Geor ...

Florida
. Hutchinson Island in particular is a major nesting area in Florida waters. Notable locations in South America include secluded beaches in
Suriname Suriname () or Surinam, officially known as the Republic of Suriname ( nl, Republiek Suriname ), is a country on the northeastern Atlantic coast of South America South America is a entirely in the and mostly in the , with a rela ...

Suriname
and
French Guiana French Guiana ( or ; french: link=no, Guyane ) is an overseas department/region and single territorial collectivity A single territorial collectivity (french: collectivité territoriale ''unique'') is a chartered subdivision of France ...

French Guiana
. In the Southern Atlantic Ocean, the most notable nesting grounds for ''Chelonia mydas'' are found on the island of Ascension, hosts 6,000–13,000 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 is a U.S. state, state located in the Southeastern United States, Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia (U.S. state), Geor ...

Florida
include
Indian River Lagoon The Indian River Lagoon is a grouping of three lagoons: the Mosquito Lagoon, the Banana River, and the Indian River (Florida), Indian River, on the Atlantic Coast of Florida; one of the most biodiverse estuaries in the Northern Hemisphere and is h ...

Indian River Lagoon
, the
Florida Keys The Florida Keys are a coral island, coral cay archipelago located off the southern coast of Florida, forming the southernmost part of the continental United States. They begin at the southeastern coast of the Florida peninsula, about south of ...
,
Florida Bay Florida Bay is the bay located between the southern end of the Florida Florida is a U.S. state, state located in the Southeastern United States, Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexic ...
,
Homosassa Homosassa is a census-designated place (CDP) in Citrus County, Florida, Citrus County, Florida, United States. The population was 2,578 at the 2010 census. History Homosassa is derived from a Seminole Indian name meaning either "river of fishes" ...
, Crystal River, and Cedar Key.


Indo-Pacific subpopulation

In the
Pacific The Pacific Ocean is the largest and deepest of Earth Earth is the third planet from the Sun and the only astronomical object known to harbour and support life. 29.2% of Earth's surface is land consisting of continents and islands. ...

Pacific
, its range reaches as far north as the southern coast of
Alaska Alaska (; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Central Alaskan Yup'ik language, Yup'ik: ''Alaskaq''; tli, Anáaski) is a U.S. state in the Western United States, on the northwest extremity of the country's West Coast of the United State ...

Alaska
and as far south as
Chile Chile, officially the Republic of Chile, is a country in the western part of South America South America is a entirely in the and mostly in the , with a relatively small portion in the . It can also be described as the southern ...

Chile
in the east. The turtle's distribution in the western Pacific reaches north to
Japan Japan ( ja, 日本, or , and formally ) is an island country An island country or an island nation is a country A country is a distinct territory, territorial body or political entity. It is often referred to as the land of an in ...

Japan
and southern parts of
Russia Russia ( rus, link=no, Россия, Rossiya, ), or the Russian Federation, is a country spanning Eastern Europe Eastern Europe is the eastern region of . There is no consistent definition of the precise area it covers, partly because th ...

Russia
's Pacific coast, and as far south as the northern tip of
New Zealand New Zealand ( mi, Aotearoa ''Aotearoa'' (; commonly pronounced by English English usually refers to: * English language English is a West Germanic languages, West Germanic language first spoken in History of Anglo-Saxon Engl ...

New Zealand
and a few islands south of
Tasmania Tasmania (), abbreviated as TAS, is an island An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atol ...
. Significant nesting grounds are scattered throughout the entire Pacific region, including
Mexico Mexico, officially the United Mexican States, is a country A country is a distinct territorial body or political entity A polity is an identifiable political entity—any group of people who have a collective identity, who are organi ...

Mexico
, the
Hawaiian Islands The Hawaiian Islands ( haw, Mokupuni o Hawai‘i) are an archipelago An archipelago ( ), sometimes called an island group or island chain, is a chain, cluster or collection of island An island (or isle) is an isolated pie ...
, the
South Pacific The South Pacific is the Southern Hemisphere portion of the Pacific Ocean, Earth's largest oceanic division, and which includes several islands and archipelagos. It may also refer to: Arts and entertainment * South Pacific (novel), ''South Paci ...

South Pacific
, the northern coast of
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

Australia
, and
Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern subregion of Asia, consisting of the regions ...

Southeast Asia
. Major Indian Ocean nesting colonies include
India India, officially the Republic of India (Hindi Hindi (Devanagari: , हिंदी, ISO 15919, ISO: ), or more precisely Modern Standard Hindi (Devanagari: , ISO 15919, ISO: ), is an Indo-Aryan language spoken chiefly in Hindi Belt, ...

India
,
Pakistan Pakistan, . Pronounced variably in English as , , , and . officially the Islamic Republic of Pakistan, is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a popul ...

Pakistan
,
Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකාව, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon, and officially the Democratic Socialist Republic of Sri Lanka, is ...

Sri Lanka
and other coastal countries. The turtles can also be found throughout the
Indian Ocean The Indian Ocean is the third-largest of the world's five ocean The ocean (also the or the world ocean) is the body of that covers approximately 70.8% of the surface of and contains 97% of . Another definition is "any of the large ...

Indian Ocean
; the east coast of the
African continent Africa is the world's second-largest and second-most populous continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, up to seven geographical r ...

African continent
hosts a few nesting grounds, including islands in the waters around
Madagascar Madagascar (; mg, Madagasikara), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), and previously known as the Malagasy Republic The Malagasy Republic ( mg, Repoblika Mal ...

Madagascar
.


Specific nesting grounds

Nesting grounds are found all along the Mexican coast. These turtles feed in seagrass pastures in the
Gulf of California The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean The Pacific Ocea ...

Gulf of California
. Green turtles belonging to the distinct Hawaiian subpopulation nest at the protected
French Frigate Shoals The French Frigate Shoals (Hawaiian Hawaiian may refer to: * Hawaii state residents, regardless of ancestry * Native Hawaiians, the current term for the indigenous people of the Hawaiian Islands or their descendants * Hawaiian language Histo ...

French Frigate Shoals
some west of the Hawaiian Islands. In the
Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

Philippines
, green turtles nest in the Turtle Islands along with closely related
hawksbill turtle The hawksbill sea turtle (''Eretmochelys imbricata'') is a critically endangered sea turtle belonging to the family Cheloniidae. It is the only extant species in the genus ''Eretmochelys''. The species has a worldwide distribution, with Atlantic ...

hawksbill turtle
s. In December 2007, fishermen using a ''hulbot-hulbot'' (a type of
fish net A fishing net is a net Net or net may refer to: Mathematics and physics * Net (mathematics) In mathematics Mathematics (from Greek: ) includes the study of such topics as numbers ( and ), formulas and related structures (), shape ...
) accidentally caught an , long and wide turtle off Barangay Bolong,
Zamboanga City , officially the (Chavacano Chavacano or Chabacano is a group of varieties spoken in the . The variety spoken in , located in the southern Philippine island group of Mindanao, has the highest concentration of speakers. Other currently exis ...
,
Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

Philippines
. December is breeding season near the Bolong beach.
Indonesia Indonesia ( ), officially the Republic of Indonesia ( id, Republik Indonesia, links=yes ), is a country in Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia or SEA, is t ...

Indonesia
has a few nesting beaches, one in the
Meru Betiri East Java ( id, Jawa Timur) is a Provinces of Indonesia, province of Indonesia. It has a land border only with the province of Central Java to the west; the Java Sea and the Indian Ocean border its northern and southern coasts, respectively, wh ...
National Reserve in
East Java East Java ( id, Jawa Timur) is a province A province is almost always an administrative division Administrative division, administrative unitArticle 3(1). , country subdivision, administrative region, subnational entity, first-level su ...

East Java
. Off the north-eastern and northern coasts of Australia, the
Great Barrier Reef The Great Barrier Reef is the world's largest coral reef A coral reef is an underwater ecosystems, ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held tog ...

Great Barrier Reef
has two genetically distinct populations; one north and one south. Within the reef, 20 separate locations consisting of small islands and
cays A cay ( or ), also spelled caye or key, is a small, low-elevation, sandy island on the surface of a coral reef A coral reef is an underwater ecosystem An ecosystem (or ecological system) consists of all the organisms and the phys ...
were identified as nesting sites for either population of ''C. mydas''. Of these, the most important is on
Raine Island Raine Island is a vegetated coral cay A cay ( or ), also spelled caye or key, is a small, low-elevation, sandy island on the surface of a coral reef A coral reef is an underwater ecosystems, ecosystem characterized by reef-building c ...
. In the
Torres Strait The Torres Strait (), also known as Zenadh Kes, is a strait A strait is a naturally formed, narrowing, typically navigable waterway that connects two larger bodies of water. The surface water generally flows at the same elevation on both ...

Torres Strait
there is a large rookery on
Bramble Cay Bramble Cay, also called Maizab Kaur, Massaramcoer or Baramaki, and located at the northeastern edge of Australia and the Torres Strait Islands of Queensland and at the northern end of the Great Barrier Reef, is the northernmost point of land of ...
. The
Coral Sea The Coral Sea () is a marginal sea This is a list of seas of the World Ocean The ocean (also the sea or the world ocean) is the body of Saline water, salt water that covers approximately 70.8% of the surface of Earth and contains 97% ...

Coral Sea
has nesting areas of world significance. Major nesting sites are common on either side of the Arabian Sea, both in Ash Sharqiyah Region (Oman), Ash Sharqiyah, Oman, and along the coast of Karachi,
Pakistan Pakistan, . Pronounced variably in English as , , , and . officially the Islamic Republic of Pakistan, is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a popul ...

Pakistan
. Some specific beaches there, such as Hawke's Bay (Karachi), Hawke's Bay and Sandspit Beach, Sandspit, are common to both ''C. mydas'' and Olive ridley sea turtle, ''L. olivacea'' subpopulation. Sandy beaches along Sindh and Balochistan (Pakistan), Balochistan are nesting sites. Some off the Geography of Pakistan, Pakistani coast, Astola, Astola island is another nesting beach.


Galápagos green turtle

The population that has often been known as the Galápagos green turtle have been recorded and observed in the Galápagos as far back as the 17th century by William Dampier. Not much attention has been paid to them due to the overwhelming research done on the Galápagos giant tortoises. Only over the last 30 years have extensive studies been performed covering the behaviors of the Galápagos green turtles. Much of the debate that has surrounded them recently is over the binomial classification of the species. At one point the name ''Chelonia agassizii'' was applied to this population as a separate species. Analysis of Mitochondrial DNA, mitochondrial and nuclear DNA of 15 nesting beaches. however has demonstrated that there is not only no significant distinction of this population but that it would be paraphyletic to recognise it. As such the species name ''Chelonia agassizzii'' is considered a junior synonym of ''Chelonia mydas'' as such it is considered as a local cariant of the populations of the East Pacific waters and those of other nesting areas. The morphological distinctiveness of the Galápagos green turtle has given rise to the debate, but evidence of taxonomic distinctiveness is best served using the combination of multiple datasets. The two most notable morphological distinctions are the considerably smaller adult size and the much darker pigmentation of the carapace, plastron, and extremities. Other distinctions are the curving of the carapace above each hind flipper, the more dome-shaped carapace, and the very long tail of adult males. Three possibilities have arisen from their unique characteristics: ''agassizii'' is a separate species from ''C. mydas'', it is a subspecies of green sea turtle, or it is simply a color mutation. These facts have led to the debate over binomial separation however due to the significance of the DNA testing results there have been no distinctions made at this time. At a meeting for sea turtle scientists and their collaborators in 2000, the evidence for the taxonomic position of the Galápagos green turtle was reviewed and a majority among the participants supported treating it as a population or subspecies of the green turtle (instead of a separate species). However, this is possibly a case of political taxonomy. As such the three major international checklists that cover turtles of the world Reptile Database the checklist of Fritz and Havas (2007) and the IUCN Checklist (TTWG 2017) all consider this a junior synonym.


Habitat

Green sea turtles move across three habitat types, depending on their Biological life cycle, 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. Green sea turtles, ''Chelonia mydas'', are classified as an aquatic species and are distributed around the globe in warm tropical to subtropical waters. The environmental parameter that limits the distribution of the turtles is ocean temperatures below 7 to 10 degrees Celsius. Within their geographical range, the green sea turtles generally stay near continental and island coastlines. Near the coastlines, the green sea turtles live within shallow bays and protected shores. In these protected shores and bays, the green sea turtle habitats include coral reefs, salt marshes, and nearshore seagrass beds. The coral reefs provide red, brown, and green algae for their diet and give protection from predators and rough storms within the ocean. The salt marshes and seagrass beds contain seaweed and grass vegetation, allowing ample habitat for the sea turtles. Turtles spend most of their first five years in convergence zones within the bare open ocean that surround them. These young turtles are rarely seen as they swim in deep, pelagic waters. Green sea turtles typically swim at .


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 A carnivore , meaning "meat eater" (Latin, ''caro'', genitive ''carnis'', meaning "meat" or "flesh" and ''vorare'' meaning "to devour"), is an organism, animal whose food and energy requirements derive solely from animal Tissue (biology), tissu ...
, pelagic organisms, part of the open ocean mininekton. In contrast, immature juveniles and adults are commonly found in
seagrass Seagrasses are the only flowering plant Flowering plants include multiple members of the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek#REDIRECT Greek Greek may refer to: Greece Anyt ...

seagrass
meadows closer inshore as herbivorous grazers.


Diet

The diet of green turtles changes with age. Juveniles are carnivorous, but as they mature they become omnivorous. Young sea turtles eat fish eggs, molluscs, jellyfish, small invertebrates, worms, sponges, algae, and crustaceans. Green sea turtles have a relatively slow growth rate because of the low nutritional value of their diet. Body fat turns green because of the consumed vegetation. This diet shift has an effect on the green turtle's skull morphology. Their serrated jaw helps them chew algae and sea grasses. Most adult sea turtles are strictly herbivorous.


Predators and parasites

Only human beings and the larger sharks feed on ''C. mydas'' adults. Specifically, tiger sharks (''Galeocerdo cuvier'') hunt adults in Hawaiian waters. Juveniles and new hatchlings have significantly more predators, including crabs, small marine mammals and shorebirds. Additionally, their eggs are vulnerable to predation by scavengers like red foxes and golden jackals. Green sea turtles have a variety of parasites including barnacles, leeches, protozoans, Cestoda, cestodes, and nematodes. Barnacles attach to the carapace, and leeches to the flippers and skin of the turtles, causing damage to the soft tissues and leading to blood loss. Protozoans, cestodes and nematodes lead to many turtle deaths because of the infections in the liver and intestinal tract they cause. The greatest disease threat to the turtle population is Turtle fibropapillomatosis, fibropapilloma, which produces lethal tumor growth on scales, lungs, stomach, and kidneys. Fibropapilloma is caused by a herpesvirus that is transmitted by leeches such as ''Ozobranchus branchiatus'', a species of leech which feeds almost entirely on green sea turtles.


Life cycle

Green sea turtles migrate long distances between feeding sites and nesting sites; some swim more than to reach their spawning grounds. Beaches in Southeast Asia, India, islands in the western Pacific, and Central America are where green sea turtles breed. 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 The Caribbean (, ; es, Caribe; french: Caraïbes; ht, Karayib; also gcf, label=Antillean Creole Antillean Creole (Antillean French Creole, Kreyol, Kwéyòl, Patois) is a French-based creole, which is primarily spoken in the Lesser Antilles ...
, mating season is from June to September. The
French Guiana French Guiana ( or ; french: link=no, Guyane ) is an overseas department/region and single territorial collectivity A single territorial collectivity (french: collectivité territoriale ''unique'') is a chartered subdivision of France ...

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 Pakistan, . Pronounced variably in English as , , , and . officially the Islamic Republic of Pakistan, is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a popul ...

Pakistan
,
Indian Ocean The Indian Ocean is the third-largest of the world's five ocean The ocean (also the or the world ocean) is the body of that covers approximately 70.8% of the surface of and contains 97% of . Another definition is "any of the large ...

Indian Ocean
turtles nest year-round, but prefer the months of July to December. Sea turtles return to the beaches on which they were born to lay their own eggs. The reason for returning to native beaches may be that it guarantees the turtles an environment that has the necessary components for their nesting to be successful. These include a sandy beach, easy access for the hatchlings to get to the ocean, the right incubation temperatures, and low probability of predators that may feed on their eggs. Over time these turtles have evolved these tendencies to return to an area that has provided reproductive success for many generations. Their ability to return to their birthplace is known as natal homing.Wynekey, J.; Lohmann, J.K.; Musick, J.A. 2013. The biology of sea turtles. CRC Press. Vol 3. Pp 59–70 The males also return to their birthplaces in order to mate. These males that return to their homes know they will be able to find mates because the females born there also return to breed. By doing this, the green sea turtles are able to improve their reproductive success and is why they are willing to expend the energy to travel thousands of miles across the ocean in order to reproduce. Mating behaviour 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 11-22 inches in depth with her hind flippers and deposits her eggs. The hole is then covered up again. Clutch size ranges between 85 and 200, depending on the age of the female. This process takes about an hour to an hour and a half. After the nest is completely covered, she returns to the sea. The female will do this 3 to 5 times in one season. The eggs are round and white, and about 45 mm in diameter. The hatchlings remain buried for days until they all emerge together at night. The temperature of the nest temperature-dependent sex determination, determines the sex of the turtles at around the 20-40 day mark. At around 50 to 70 days, the eggs hatch during the night, and the hatchlings instinctively head directly into the water. This is the most dangerous time in a turtle's life. As they walk, predators, such as gulls and crabs, 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. It is estimated that only 1% of hatchlings reach sexual maturity. Each year on Ascension Island in the South Atlantic, ''C. mydas'' females create 6,000 to 25,000 nests. They are among the largest green turtles in the world; many are more than a metre in length and weigh up to .


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 trawlers and other fishing gear. During the night while sleeping and to protect themselves from potential predators, the adults wedge themselves under rocks below the surface and under ledges in reefs and coastal rocks. Many green sea turtles have been observed in returning to the same sleeping location night after night.


Physiology and sensory modalities

Green sea turtles tend to have good vision, well adapted to a life at sea. The turtles can see many colors, but are most sensitive to light from violet to yellow or wavelengths of 400 to 600 nanometers. They do not see many colors in the orange to red portion of the light spectrum. On land, however, the sea turtles are nearsighted because the lenses in the eyes are spherical and adjusted to refraction underwater. Sea turtles have no external ear and only one ear bone, called the columella. With one ear bone, the turtles can hear only low frequency sounds, from 200 to 700 Hz. Sounds can also be detected through vibrations of the head, backbone, and shell. The nose of the turtle has two external openings and connects to the roof of the mouth through internal openings. The lower surface of the nasal passage has two sets of sensory cells called the Jacobson's organ. The turtle can use this organ to smell by pumping water in and out of its nose. Since green sea turtles migrate long distances during breeding seasons, they have special adaptive systems in order to navigate. In the open ocean, the turtles navigate using wave directions, sun light, and temperatures. The sea turtles also contain an internal magnetic compass. They can detect magnetic information by using magnetic forces acting on the magnetic crystals in their brains. Through these crystals, they can sense the intensity of Earth's magnetic field and are able to make their way back to their nesting grounds or preferred feeding grounds. Natal homing is an animal's ability to return to its birthplace in order to reproduce. Natal homing is found in all species of sea turtles and in other animals such as salmon. How these turtles are able to return to their birthplace is an interesting phenomenon. Many researchers believe that sea turtles use a process called imprinting, which is a special type of learning that occurs when turtles first hatch that allows them to recognize their native beach. There are two types of imprinting that are thought to be the reason turtles can find these beaches. The first is the chemical imprinting hypothesis. This hypothesis states that much like salmon, sea turtles are able to use olfactory cues and senses to smell their way home. However, a problem with this hypothesis is that some turtles travel thousands of miles to return to their native beaches, and the scents from that area aren't likely to travel and be distinguishable from that distance. The second hypothesis is the geomagnetic. This hypothesis states that as it hatches, a young turtle will imprint on the magnetic field of the beach they are born on. This hypothesis strongly correlates to the method which sea turtles use to navigate the earth. In order to tolerate the constant heat loss in the water, sea turtles have the ability to shunt blood away from tissues that are tolerant of low oxygen levels toward the heart, brain, and central nervous system. Other mechanisms include basking on warm beaches and producing heat through their activity and movements of their muscles. In the winter months, turtles living at higher latitudes can hibernate for a short period in the mud.


Unique characteristics and features

The green sea turtles exhibit sex differences by their development and appearance. As adult turtles, males are easily distinguishable from the females by having a longer tail (visibly extending past the shell) and longer claws on the front flippers. The hatching time and sex of the turtles are determined by the incubation temperature of the nest. Hatchings occur more quickly in nests that are warmer than nests that are in cooler conditions. Warm nesting sites above 30 degrees Celsius favor the development of females, whereas nesting sites below 30 degrees Celsius produce males. The position of the egg in the nest also affects sex-determination. Eggs in the center tend to hatch as females due to the warmer conditions within the nest. Green sea turtles play an essential role in the ecosystem in which they live. In the seagrass beds, the turtles feed on the seagrass by trimming only the top and leaving the roots of the plant. Through their feeding technique, the turtles help to improve the health and growth of the seagrass beds. The healthy seagrass beds that the turtles provide give habitat and feeding grounds for many species of fish and crustaceans. On the nesting beaches, the green sea turtles provide key nutrients for the ecosystem through their hatched egg shells. In their coral reef habitat, the green sea turtles have a Symbiosis, symbiotic interaction with reef fish, including the yellow tang. The yellow tang fish swims along with the turtle and feeds on the algae, barnacles, and parasites on its shell and flippers. This species interaction provides food for the yellow tang and provides a necessary cleaning and smoothing of the turtle's shell. This cleaning helps the turtles swim by reducing the amount of drag and improves their health.


Importance to humans

Historically, the turtles' skin was Tanning (leather), tanned and used to make handbags, especially in
Hawaii Hawaii ( ; haw, Hawaii or ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspape ...

Hawaii
. History of China#Ancient China, Ancient Chinese considered the flesh of sea turtles a culinary delicacy, including and especially ''C. mydas''. Particularly for this species, the turtle's body fat, fat, cartilage, and flesh, known as calipee, are sought as ingredients for making turtle soup, a popular 19th-century American dish. In Java,
Indonesia Indonesia ( ), officially the Republic of Indonesia ( id, Republik Indonesia, links=yes ), is a country in Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia or SEA, is t ...

Indonesia
, sea turtle eggs were a popular delicacy. However, the turtle's flesh is regarded as ''ḥarām'' or "unclean" under Sharia, 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 List of islands of Indonesia, Indonesian archipelago. Bali has been importing sea turtles since the 1950s, as its own turtle supplies became depleted. Sumertha, I.N. 1974. Perikanan penyu dan cara pengelolaan di Indonesia. ''Dokumen. Kom. IPB'' 8: 1–18. Cited in The mostly Hindu Balinese people, Balinese do not eat the eggs, but sell them instead to local Muslims. Commercial farms, such as the Cayman Turtle Farm in the West Indies, once bred them for commercial sale of turtle meat, turtle oil (rendered from the fat), turtle shell, and turtle leather made from the skin. The farm's initial stock was in large part from "doomed" eggs removed from nests threatened by erosion, flooding, or in chemically hostile soil. The farms held as many as 100,000 turtles at any one time. When the international markets were closed by regulations that did not allow even farm-bred turtle products to be exported internationally, the surviving farm became primarily a tourist attraction, supporting 11,000 turtles. Initially started as Mariculture Ltd., then Cayman Turtle Farm Ltd and subsequently branded Boatswain's Beach, in 2010 the farm's brandname was changed to Cayman Turtle Farm: Island Wildlife Encounter. Sea turtles are integral to the history and culture of the Cayman Islands. When the islands were first discovered by Christopher Columbus in 1503, he named them "Las Tortugas" because of the abundance of sea turtles in the waters around the islands. Many of the earliest visitors came to the Cayman Islands to capture the turtles as a source of fresh meat during long voyages. The green turtle is a national symbol displayed as part of the coat of arms of the Cayman Islands, which also forms part of the national flag of the Cayman Islands. The country's currency uses a turtle as the watermark in its banknotes. A stylised sea turtle nicknamed "Sir Turtle" is the mascot of the national airline Cayman Airways and is part of the livery of its aircraft. A ki'i pōhaku (petroglyph) of a turtle (or honu) can be found on The Big Island of Hawaii in the Pu'u Loa lava fields. The green sea turtle (called Honu) has always held a special meaning for Hawaiians and this petroglyph shows its importance dating to possibly when the islands first became populated. The turtle symbolizes a navigator that can find his way home time after time. This symbol mirrors the real life of the green Hawaiian turtle as it will swim hundreds of miles to lay its eggs at its own place of birth. Though there are other myths as well, some Hawaiian legends say the honu were the first to guide the Polynesians to the Hawaiian Islands. Hawaiians revere the turtle and the legend of Kailua, a turtle who could take the form of a girl at will. In human form, she looked after the children playing on Punalu'u beach.


Conservation

In recent decades, sea turtles have moved from unrestricted exploitation to global protection, with individual countries providing additional protection, although serious threats remain unabated. All populations are considered "threatened".


Threats

Human action presents both intentional and unintentional threats to the species' survival. Intentional threats include continued turtling (hunting), hunting, poaching and egg harvesting. More dangerous are unintentional threats, including boat strikes, fishermen's nets that lack turtle excluder devices, pollution and habitat destruction. Chemical pollution may create tumors; effluent from harbors near nesting sites may create disturbances; and light pollution may disorient hatchlings. With chemical pollution present, there is a development of tar balls that is often eaten by green sea turtles in a confusion of their food. Tar balls cause the green sea turtle to intake toxins that can block their guts, displace the liver and intestines causing swelling of the tissue. 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, Turtle fibropapillomatosis, 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. In addition, at least in the Southwestern Atlantic (Río de la Plata, Uruguay), exotic invasive species such as the rapa whelk Rapana venosa, were reported massively bio-fouling immature green turtles, reducing buoyancy, increasing drag, and causing severe injuries to the carapace. Because of these threats, many populations are in a vulnerable state. Pacific green turtles' foraging habitats are poorly understood and mostly unknown. These foraging grounds are most likely along the coast of Baja California, Mexico and southern California,National Marine Fisheries Service and U.S. Fish and Wildlife Service. 1998. Recovery Plan for U.S. Pacific Populations of the East Pacific Green Turtle (''Chelonia mydas''). National Marine Fisheries Service, Silver Spring, MD. in which these turtles 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. In addition there are indications that global climate change is affecting the ability of green turtle populations in Australia to produce males due to their temperature-dependent sex determination and the rising temperatures in the northern
Great Barrier Reef The Great Barrier Reef is the world's largest coral reef A coral reef is an underwater ecosystems, ecosystem characterized by reef-building corals. Reefs are formed of Colony (biology), colonies of coral polyp (zoology), polyps held tog ...

Great Barrier Reef
region. Construction of new thermal power stations can raise local water temperature, which is also said to be a threat. Green sea turtles are the most commonly traded species along Java's south coast and are sold in the form of whole, stuffed animals or turtle oil, locally known as "minyak bulus". The geographer James J. Parsons' book titled ''The Green Turtle and Man'' played a special role in the conservation movement to save the species from extinction.


Global initiatives

The International Union for Conservation of Nature (IUCN) has repeatedly listed green sea turtles in its IUCN Red List of Threatened Species, Red List under differing criteria. In 1982, they officially classified it as an endangered species. 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 3 May 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 is a family of typically large marine turtles that are characterised by their common traits such as, having a flat streamlined wide and rounded shell and almost paddle-like flippers for their forelimbs. The six species that make up thi ...
. 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, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

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 Zoological Society of London has listed the reptile as an EDGE species. 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 the State of
Hawaii Hawaii ( ; haw, Hawaii or ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspape ...

Hawaii
, specifically on the Island of Hawai'i (Hawaii County), state representative Faye Hanohano, a Native Hawaiian rights activist, pressed for a measure to delist ''C. mydas'' from protected status so that Native Hawaiians could legally harvest the turtles and possibly their eggs as well. The bill, HCR14, was largely overlooked by the media since at that point it was only a local issue. While the bill was passed in the United States House of Representatives, the United States Senate, United States Senate's Committee on Energy and Environment refused to hear it, which meant that the bill did not go on to be heard by the Senate.


Country-specific initiatives

In addition to management by global entities such as the IUCN and CITES, specific countries around the world have undertaken conservation efforts. The
Indonesia Indonesia ( ), officially the Republic of Indonesia ( id, Republik Indonesia, links=yes ), is a country in Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia or SEA, is t ...

Indonesia
n island of Bali has traditional uses that were considered 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. Multiple List of protected areas of the Philippines, protected areas of the Philippines have significant green sea turtle nesting and feeding sites. The most notable is Turtle Islands, Tawi-Tawi, Turtle Islands Wildlife Sanctuary, an UNESCO tentative site which encompasses an entire municipality and one of Southeast Asia's most important green sea turtle nesting sites. Other notable sites include the UNESCO tentative site of El Nido-Taytay Management Resource Protected Area and the UNESCO World Heritage Site of Tubbataha Reefs Natural Park. The species is protected under Republic Act 9147 or the Wildlife Resources Conservation and Protection Act, while the sites where they live and nest are protected under the National Integrated Protected Areas System Act. Ecotourism is one initiative in Sabah,
Malaysia Malaysia ( ; ) is a country in Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia or SEA, is the geographical southeastern subregion of Asia, consisting of the regions ...

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. The
Hawaii Hawaii ( ; haw, Hawaii or ) is a state State may refer to: Arts, entertainment, and media Literature * ''State Magazine'', a monthly magazine published by the U.S. Department of State * The State (newspaper), ''The State'' (newspape ...

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 on Hawaii (island), 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
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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. Cayman Turtle Farm located in Grand Cayman in the northwest Caribbean Sea is the first farm to have achieved the second generation of green sea turtles bred, laid, hatched, and raised in captivity. Since its beginning in 1968, the farm has released over 31,000 turtles into the wild, and each year more captive-bred turtles are released into the Caribbean Sea from beaches around the island of Grand Cayman. Captive-bred turtles released from the farm as hatchlings or yearlings with "living tags," have now begun to return to nest on Grand Cayman as adults. On February 19, 2012 the farm released the first 2nd-generation captive-bred green sea turtle equipped with a Position Tracking Transponder, or PTT (also known as a satellite tag). In addition, the farm provides turtle meat products to the local population for whom turtle has been part of the traditional cuisine for centuries. In so doing, the farm curtails the incentive to take turtles from the wild, which over the years in addition to the Cayman Turtle Farm's release of captive-bred turtles has enabled an increase in the number of turtles sighted in the waters around the island of Grand Cayman and nesting on its beaches. In the Pacific, green sea turtles nest on the ''motu'' (islets) in the Funafuti Conservation Area, a marine conservation area covering 33 square kilometers (12.74 square miles) of reef, lagoon and ''motu'' on the western side of Funafuti atoll in Tuvalu. On
Raine Island Raine Island is a vegetated coral cay A cay ( or ), also spelled caye or key, is a small, low-elevation, sandy island on the surface of a coral reef A coral reef is an underwater ecosystems, ecosystem characterized by reef-building c ...
, up to 100,000 nesting females have been observed in a season, with the cay producing 90% of the region's green turtles. However, the hatching rate declined in the 1990s, and a further decline in the population was threatened by the deaths of thousands of females as they struggled to climb the small sandy cliffs. In addition, as the shape of the island had changed over time, the spread of the beaches outwards had led to greater risk of inundation of the turtle nests. Between 2011 and 2020, a collaborative project by the Queensland Government, BHP (as corporate sponsor), the Great Barrier Reef Marine Park Authority, Great Barrier Reef Foundation, and Wuthathi and Meriam people, Meriam traditional owners, reshaped the island using heavy machinery in a way that gave the female turtles a smoother passage and reduced the risk of nest inundation. A sophisticated monitoring and research system, using 3D modelling, satellite technology and Unmanned aerial vehicle, drones was employed, and monitoring continues. , a project called "The Turtle Cooling Project" is being undertaken by scientists from the World Wildlife Fund Australia, University of Queensland, Deakin University and the Queensland Government. It is looking at the effect of global warming on northern green turtle breeding, in particular the effect of producing more male turtles owing to the higher temperatures. They are working in the area around Raine Island, Heron Island (Queensland), Heron Island and Moulter Cay.


Genetics

The genome of ''Chelonia mydas'' was sequenced in 2013 to examine the development and evolution of the turtle body plan.


See also

* Sea Turtle Association of Japan, Kuroshima Research Station * T. K. Bellis, T.K. Bellis The "Turtle King".


References


External links

* *
Images and movies (''Chelonia mydas'')
ARKive

US Fish and Wildlife Service
Desktop wallpaper & fun green turtle factsGreen turtle video
– Macaulay Library
Baby green sea turtles
– Open Water 859 * {{DEFAULTSORT:turtle, sea, green Chelonia, green sea turtle Sea turtles, green sea turtle Pantropical fauna Fauna of Ascension Island Reptiles of the Dominican Republic Marine fauna of Northern Australia Natural history of Balochistan, Pakistan Endangered species Species endangered by habitat loss Reptiles described in 1758, green sea turtle Taxa named by Carl Linnaeus