A large marine turtle, reaching up to 1,200 mm in carapace length; largest Egyptian specimen is 1,190 mm. Carapace depressed, rounded, smooth; scutes juxtaposed; posterior edge without indentations; 4 coastal scutes; first marginal scute in contact with first vertebral scute. Head relatively small with a single pair of prefrontals. C. mydas differs from all other marine turtles in possessing serrations on the lower jaw, which facilitate grazing on marine grasses. Forelimbs and hind limbs have a single claw each. Males smaller, with longer tails and larger claws. Color of carapace light brown with dark streaks radiating out from a point at the posterior margin of each scute. Dorsal sides of limbs and head brown, each scale edged yellowish. All ventral sides whitish yellow.

Green turtles are found in tropical and portions of subtropical oceans worldwide. They are found in the Atlantic Ocean from the eastern United States along coastal South America to South Africa. They are found throughout the Caribbean Sea and portion of the Mediterranean. They are also found throughout the warm waters of the Indian and Pacific Oceans.

Biogeographic Regions: indian ocean (Native ); atlantic ocean (Native ); pacific ocean (Native ); mediterranean sea (Native )

Known from Egyptian waters in both the Mediterranean and Red Sea. The only reliable evidence of nesting on the Mediterranean shores is a nest with eggs found near Zaranik, North Sinai, in the summer of 1998 (Clarke et al. 2000). A dead juvenile (carapace length 85 mm) found at Baltim could have originated from elsewhere. Dead individuals are frequently encountered throughout the Egyptian Mediterranean shoreline. In the Red Sea the species has been recorded from both the Gulfs of Suez and Aqaba, and has been reported to have nested at Ras Sharatib, south of Abu Rudeis (where some 80 females were estimated to nest),Tiran Island, Qulan Islands, Wadi El Gemal Island, Ras Banas, and Zabargad Island. Eggs and embryos from Giftun El Kebir Island referred to this species by Marx (1968), were re-identified as Eretmochelys imbricata by (Frazier and Salas 1984). The species nests sporadically along the mainland shores of the Red Sea south of Marsa Alam, where almost a hundred nests have been found between Ras Baghdadi and Marsa um El Abbas.

Circum-global, largely within the 20°c oceanic isotherms.

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Distribution is pantropical in the Atlantic, Pacific, and Indian oceans. In some areas this species occurs in higher temperate latitudes due to drifting in ocean currents in conjunction with above-normal sea temperatures or as a normal life history event; young turtles regularly range as far north as New England. Major nesting activity occurs on Ascension Island, Aves Island, in Costa Rica (24,000 females nests each year at Tortuguero), and in Surinam (CSTC 1990). See Hirth (1980) for a map of major nesting beaches.

In U.S. Atlantic waters, green sea turtles occur around the U.S. Virgin Islands and Puerto Rico, where small numbers nest (islas Mona, Vieques, and Culebra, and St. Thomas, St. John, St. Croix), and a juvenile population exists in eastern portion of Puerto Rican Bank (Collazo et al. 1992), and from Texas to Massachusetts. Relatively small numbers nest in Florida, particularly in Brevard, Indian River, St. Lucie, Martin, Palm Beach, and Broward counties (CSTC 1990), mostly from Volusia County to Dade County (Ehrhart and Witherington 1992), with rare recent nesting on the Gulf Coast in Santa Rosa County (Ehrhart and Witherington 1992); important feeding areas in Florida include the Indian River, Florida Bay, Homossassa Bay, Crystal River, and Cedar Key (CSTC 1990). Rarely nests in Georgia, North Carolina, and Texas.

They are called green turtles because of the color of the flesh. Chelonia mydas are one of the largest turtles ranging from 71 to 153 centimeters. They can weigh up to 205 kilograms. They have limbs that are paddle-like, which are used to swim. Their heads seem small compared to their body size. Males are larger than females and the tail is longer, extending well beyond the shell. The carapace can be olive to brown, or sometimes black, depending on the geographic location of the species. Green turtles cannot pull their heads inside of their shells. There are two sub-species which include Chelonia mydas mydas and Chelonia mydas agassizii. The common name for Chelonia mydas mydas is the Atlantic green turtle, which lives in the Atlantic ocean and has been see off the shores of Europe and North America. Chelonia mydas agassizii, or Eastern Pacific green turtle and sometimes black sea turtle because of its dark colored carapace, has been see off the coasts of Alaska, through California, and to Chile. Some features that distinguish C. m. agassizii from C. m. mydas are that the shell of C. m. agassizii is higher, the shell is narrower, the marginals are more constricted over the hind legs, and the postcentral lamina are longer relative to their width (Ernst 1994). The Pacific and Atlantic populations have been separated for millions of years.

Range mass: 0 to 0 kg.

Average mass: 205 kg.

Length: 122 cm

Weight: 200000 grams

Differs from the hawksbill in having one rather than two pairs of prefrontals and carapace scutes that do not overlap. Differs from the loggerhead and the ridleys in having the first costal not in contact with the nuchal.

• Terrestrial
• Marine

Green sea turtles live in tropical waters all over the world. The only time they emerge from the water is when they are nesting. The only time males are not at sea is when they were first born. C. m. agassizii are sometimes found with seals and albatrosses basking on the beach (Pritchard 1967). When it is time to mate they migrate from several hundred to over a thousand miles across the ocean to where they hatched. Female green turtles use the same beaches to nest as their mothers and grandmothers.

Aquatic Biomes: coastal

Warm marine waters. Frequently segrass beds, which by nature are in fairly shallow, sandy, inshore habitats. Often near wadi deltas (In the Red Sea), where the fringing reef is broken and suitable sandy substrate in shallow waters is available. Generally, the availability of suitable seagrass beds is limited in the Egyption Red Sea, and apparently so in the Mediterranean as well, given the small number of records in Egyption territory. Nesting in the Red Sea has been recorded in the months of June and July. Sexual maturity reached between 12 and 50 years, depending on location and nutritional history.

Comments: Feeding occurs in shallow, low-energy waters with abundant submerged vegetation, and also in convergence zones in the open ocean (NMFS and USFWS 2007). Migrations may traverse open seas. Adults are tropical in distribution, whereas juveniles range into temperate waters (e.g., see Morreale and Standora, no date). Hatchlings often float in masses of marine macroalgae (e.g., Sargassum) in convergence zones. Coral reefs and rocky outcrops near feeding pastures often are used as resting areas. Inactive individuals may rest on the bottom in winter in the northern Gulf of California. Basking on beaches occurs in some areas (e.g., Hawaii).

Nesting occurs on beaches, usually on islands but also on the mainland. Sand may be coarse to fine, has little organic content; physical characteristics vary greatly in different regions. Most nesting occurs on high energy beaches with deep sand. At least in some regions, individuals generally nest at same beach (apparently the natal beach, Meylan et al. 1990, Allard et al. 1994) in successive nestings, though individuals sometimes change to a different nesting beach within a single nesting season (has switched to beach up to several hundred kilometers away) (see Eckert et al. 1989). Beach development and illumination often make beaches unsuitable for successful nesting.

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

Adults migrate up to about 3,000 km between nesting beaches and feeding areas (e.g., between Ascension Island and the South American coast). See Balazs (1982) for a map of documented migrations between the major nesting area in Hawaii (French Frigate Shoals) and foraging areas elsewhere in the Hawaiian Islands. See Morreale and Standora (no date) for information on movements along the east coast of the United States.

Seminoff et al. (2002) documented migration between nesting area on the coast of Michoacan (Mexico; January 2000) and a feeding ground on the Sonoran coast of the Gulf of California (Mexico; September 2000).

See Mortimer and Porter (1989) for information on internesting movements at Ascension Island.

Neonates migrate far from natal beaches to foraging areas and return to natal beach to breed/nest up to 40+ years later.

Green turtles are mostly herbivorous. They spend most of their time feeding on algae in the sea and the grass that grow in shallow waters. As juveniles, they eat plants and other organisms such as: jellyfish, crabs, sponges, snails, and worms. As adults, they are strictly herbivorous (Ernst 1994).

Comments: Diet includes"seagrass," macroalgae and other marine vegetation, and various invertebrates such as mollusks, sponges, crustaceans, and jellyfish.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: This species is represented by a large number of nesting occurrences (more than 150 major and minor nesting areas in more than 80 nations worldwide).

100,000 to >1,000,000 individuals

Comments: At 46 nesting areas worldwide, representing most but not all of the global population, the latest data indicate that approximately 109,000-151,000 females nest each year (NMFS and USFWS 2007). Assuming an average remigration interval of 3 years, this indicates an adult female population size of roughly 327,000-453,000. Assuming an equal number of adult males yields 654,000-906,000 adults for this subset of the global population.

Eggs and hatchlings typically incur high mortality from various terrestrial and aquatic predators, including both vertebrates and invertebrates (e.g., crabs). Many nests are destroyed by tidal inundation and erosion. In Costa Rica, annual survivorship of adult females was 0.61; in various areas egg survivorship was 0.40-0.86 (see Iverson [1991] for a compilation of survivorship data). Humans are the most important predators on adults. See Witherington and Ehrhart (1989) for information on cold stunning in Florida.

Herbivorous, feeding largely on marine grasses and algae when adult; young carnivorous, pelagic.

Comments: Turtles in the northern Gulf of California overwinter in a dormant condition. Nesting occurs generally at night. In Hawaii, green sea turtles may bask on beaches mid-morning to mid-afternoon, especially after a period of rainy weather (Whittow and Balazs 1982).

Average lifespan

Status: captivity: 75 years.

Males and females mature between 10 and 24 years. The breeding season depends on the latitude. Internal fertilization takes place when the male and female copulate. This is the only time there is vocalization. Like many species, there is male competition. One male may try to bite another male who is copulating with a female. Mating occurs underwater or on the surface about one kilometer from the shore. Sometimes the female will retain enough sperm to nest several times that year. Nesting occurs every three to six years. When the female is ready to lay her eggs, she leaves the water, crawls onto the sand and starts digging for hour and hours until her flippers will not allow her to dig deeper. She then lays 100 to 200 eggs. This group of eggs is called a clutch. She covers them with sand to protect them from the sun, heat, and predators. Pacific green turtles lay fewer eggs than Atlantic green turtles. The gestation period is 40 to 72 days, depending on the location.

Average gestation period: 59 days.

Average number of offspring: 150.

Average age at sexual or reproductive maturity (male)

Sex: male: 3650 days.

Average age at sexual or reproductive maturity (female)

Sex: female: 3650 days.

Individual reproductive females lay 1-8 clutches per season, averaging about 90-140 eggs, at about two-week intervals usually every 2-5 years. Nesting occurs March-October in Caribbean-Gulf of Mexico region, with peak in May-June; nests in Florida May-September (Ehrhart and Witherington 1992). Nesting encompasses April-October, with a peak between mid-June and early August, in Hawaii (Niethammer et al. 1997). Eggs hatch usually in 1.5-3 months. Hatchlings emerged between early July and late December (peak mid-August to early October) in Hawaii (Niethammer et al. 1997). Females mature probably at an average age of 27 years in Florida, but growth rates and hence age of maturity may vary greatly (from perhaps fewer than 20 years to 40+ years) throughout the range (slower growth in Australia, Hawaii, and Galapagos than in Florida and West Indies region).

The shell of some sea turtles allows for different levels of buoyancy for juveniles and adults by changing shape.

Green turtles are an endangered species because they have so many predators--including humans. Even though a female can lay over 200 eggs in on clutch, some will not hatch, and many will be eaten. Even if they do hatch, they get eaten on their way to the water, and in the water. So only a few will survive if any. If the they do survive, they can live to be over 100 years old. Sometimes eggs are laid on a public beach. When this happens conservationists come and move them to a safer place. In the United States, green turtles are protected by the Endangered Species Act.

US Federal List: endangered

CITES: appendix i

IUCN Red List of Threatened Species: endangered

Uncommon, localized and declin­ing. Facing a variety of threats in Egypt, most importantly as a by-catch of commercial fishing vessels. The species along with other marine tur­tles are consumed in some Egyptian coastal cities. Loss of nesting beaches is also a problem particularly in the Red Sea.

Endangered

United States

Rounded National Status Rank: N3B,N3N : N3B: Vulnerable - Breeding, N3N: Vulnerable - Nonbreeding

Rounded Global Status Rank: G3 - Vulnerable

Reasons: Distributed worldwide in warm oceans; exploited heavily for meat and eggs and as a component of other products; nesting and feeding habitats are being destroyed or degraded by pollution and development; large decline over the long term, more recently possibly stable or increasing in some areas.

Environmental Specificity: Very narrow to narrow.

Other Considerations: Individuals migrate up to 2,000 km between nesting beaches and feeding areas. Hence local populations may experience negative impacts from distant threats.

Global Short Term Trend: Decline of 30-70%

Comments: The Marine Turtle Specialist Group of the World Conservation Union analyzed population trends at 32 index nesting sites around the world and found a 48-65% decline in the number of mature females nesting annually over the past 100-150 years (this represents 3 generations).

In a couple dozen areas for which recent data are available, most populations were stable or increasing (19 or 23) (NMFS and USFWS 2007). These trends should be interpreted with caution because events that affected juvenile recruitment up to several decades ago may continue to affect nesting populations.

Global Long Term Trend: Decline of 30-70%

Comments: Number of subpopulations and especially population size undoubtedly have undergone a major decline over the long term.

Degree of Threat: B : Moderately threatened throughout its range, communities provide natural resources that when exploited alter the composition and structure of the community over the long-term, but are apparently recoverable

Comments: Major threats, which vary throughout the range, include degradation of nesting habitat, including beach lighting, which may disorient hatchlings and/or nesting females; human predation on nesting females and turtles in foraging areas (e.g., for meat and use in commericial products); collection of eggs for human consumption; predation on eggs and hatchlings by raccoons, dogs, etc.; mortality in fishing gear and other entangling debris; collisions with power boats; contact with chemical pollutants; and epidemic outbreaks of fibropapilloma or "tumor" infections (Mitchell 1991, Ehrhart and Witherington 1992, Tuato`o-Bartley et al. 1993, Losey et al. 1994, Barrett 1996, NMFS and USFWS 2007). In the north, juveniles experience periodic mortality due to cold-stunning associated with rapid temperature declines in fall. See USFWS (1998) and NMFS and USFWS (2007) for further information on certain threats, including beach erosion, beach armoring, beach nourishment, artificial lighting, beach cleaning, increased human presence, recreational beach equipment, exotic dune and beach vegetation, nest loss to abiotic factors, predation, poaching, and disease.

Restoration Potential: Pattern of nesting on natal beach may inhibit natural recolonization of breeding sites of decimated populations.

Preserve Selection and Design Considerations: Local foraging populations may consist of individuals from widely separated nesting populations. For example, mtDNA data indicate that a foraging population of juveniles from Hutchinson Island, Florida, consisted of individuals from Costa Rica, United States and Mexico, and Aves Island (Venezuela and Surinam; another population of juveniles from the Bahamas represented Costa Rica, United States and Mexico, Aves Island and Suriname, and Ascension Island and Guinea Bissau (Bass and Witzell 2000). Thus the success of preserves for foraging juveniles may depend on cooperative international management (Bass and Witzell 2000).

Management Requirements: Frazer (1992) emphasized the primary need for clean and productive marine and coastal environments; installation of turtle excluder devices in shrimp trawl nets and use of low pressure sodium lighting on beaches were suggested as appropriate sea turtle conservation technologies, whereas headstarting, captive breeding, and hatcheries were regarded as ineffective at best. "Head-starting" and broad-scale nest translocation remain unproven as effective management measures (Ehrhart and Witherington 1992). See Bjorndal (1982) for several papers containing management and research recommendations and discussion of conservation issues.

See NMFS (Federal Register, 19 December 1996, pp. 66933-66947) for recent amendments to regulations pertaining to the use of turtle excluder devices along the Gulf and Atlantic coasts of the southeastern U.S. See NMFS (1993) for recent shrimp trawling regulations for an area off the coast of North Carolina (allow tow-time limits as an interim alternative to the use of turtle excluder devices).

If beach lighting cannot be eliminated, low pressure sodium vapor lights may be the least disruptive to nesting turtles (Witherington 1992).

A recovery plan is available; see Marine Turtle Recovery Team (1984). See also recovery plans for U.S. Pacific and east Pacific populations (NMFS 1998) .

[Move to GPROTNEED: Ehrhart and Witherington (1992) emphasized the need to protect nesting areas in southern Brevard and northern Indian River counties in southeastern Florida.]

Biological Research Needs: Better information is needed on demography, migrations, and developmental requirements.

Needs: Foraging, developmental, and nesting habitat need protection from from any type of human activity. Purchase of turtle products should be discouraged.

See "Recovery plan for U.S. Pacific populations of the green turtle (Chelonia mydas)" and "Recovery plan for U.S. Pacific populations of the east Pacific green turtle (Chelonia mydas)."

According to "The Official World Wildlife Fund Guide to Endangered Species of North America," in some areas of the world such as the Caribbean, Mexico, and South America, green sea turtles are an important source of food for humans. They are captured and their meat is used for turtle soup (Behler, 1998).

Comments: Adults and eggs are harvested for human consumption in many areas, also for skins and oil for the leather and cosmetics trade. See Mack et al. (1982) for information on commercial exploitation. See Luxmoore and Canin (1985) for information on international trade in shell in the late 1970s and early 1980s.

Comments: Eastern Pacific populations of Chelonia are regarded by some authors as a distinct species, the black turtle, C. agassizii (King and Burke 1989); other authors (e.g., Ernst and Barbour 1989) retain agassizii as a subspecies of C. mydas (Kamezaki and Matsui 1995) or do not recognize it taxonomically at all (Crother et al. 2000). Phylogenetic analyses of mtDNA data by Bowen et al. (1992) yielded no evidence of matrilineal distinctiveness of agassizii. See Karl and Bowen (1999), Pritchard (1999), Grady and Quattro (1999), Shrader-Frechette and McCoy (1999), and Bowen and Karl (1999) for further debate about the taxonomic status of the black turtle.

The Australian flatback turtle, formerly known as Chelonia depressa, has been removed to its own genus, Natator (Zangerl et al. 1988, Limpus et al. 1988). MtDNA data indicate a fundamental phylogenetic split distinguishing all green turtles in the Atlantic-Mediterranean from those in the Indian-Pacific oceans (Bowen et al. 1992).

Most regional populations of Chelonia mydas are genetically distinct (Bowen et al. 1992). Florida population is characterized by unusually high mtDNA diversity (Allard et al. 1994).