CDC Logo

BC Conservation Data Centre: Species Summary


Chelonia mydas
Green Sea Turtle

 
Scientific Name: Chelonia mydas (Linnaeus, 1758)
English Name: Green Sea Turtle
 
Classification / Taxonomy
Scientific Name - Concept Reference: King, F. W., and R. L. Burke, editors. 1989. Crocodilian, tuatara, and turtle species of the world: a taxonomic and geographic reference. Association of Systematics Collections, Washington, D.C. 216 pp.
Classification Level: Species
Species Group: Vertebrate Animal
Species Code: R-CHMY
Kingdom Phylum Class Order Family
Animalia Craniata Chelonia Testudines Cheloniidae
   
Conservation Status / Legal Designation
Global Status: G4 (Oct 2025)
Provincial Status: SNA (Mar 2025)
BC List: Accidental
Provincial FRPA list:   
Provincial Wildlife Act:
COSEWIC Status:
SARA Schedule:
General Status Canada:
   
Ecology & Life History
General Description: A sea turtle with a brown carapace, often with radiating mottled or wavy dark markings or large dark brown blotches; 4 costal plates on each side of carapace; first costal does not contact the nuchal; one pair of prefrontal plates between the eyes; limbs are flattened flippers; young are black to dark brown above, mainly white below, with a middorsal keel and two plastral keels, 4-6 cm at hatching; adult carapace length usually 90-122 cm (to 153 cm), mass 113-204 kg (to 295+ kg) (Conant and Collins 1991).
Global Reproduction Comments: 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).
Global Ecology Comments: 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.
Migration Characteristics:
(Global / Provincial)		 
    Nonmigrant:
    Local Migrant:
    Distant Migrant:
    Within Borders Migrant: 		N /
N /
Y /
na /
Global Migration Comments: 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.
Habitats:
(Type / Subtype / Dependence) 		Ocean / Eelgrass Beds / Obligate
Ocean / Intertidal Marine / Obligate
Ocean / Kelp Bed / Obligate
Ocean / Marine Island / Obligate
Ocean / Pelagic / Obligate
Ocean / Reefs / Obligate
Ocean / Sheltered Waters - Marine / Obligate
Ocean / Subtidal Marine / Obligate
Global Habitat 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.
Food Habits: Herbivore: Adult, Immature
Invertivore: Adult, Immature
Global Food Habits Comments: Diet includes"seagrass," macroalgae and other marine vegetation, and various invertebrates such as mollusks, sponges, crustaceans, and jellyfish.
Global Phenology: Circadian: Adult, Immature
Global Phenology 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).
Provincial Phenology:
(1st half of month/
2nd half of month)
Colonial Breeder: Y
Length(cm)/width(cm)/Weight(g): 122/ / 200000
Elevation (m) (min / max): Global: 
Provincial: 
   
 
Distribution
Endemic: N
Global Range Comment: 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 (British Overseas Territory), Aves Island (Venezuela), Tortuguero, Costa Rica, and in Suriname (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.
 
Authors / Contributors
Global Information Author: Hammerson, G.
Last Updated: Feb 11, 2009
Provincial Information Author:
Last Updated:
   
References and Related Literature
Allard, M. W., et al. 1994. Support for natal homing in green turtles from mitochondrial DNA sequences. Copeia 1994:34-41.
Balazs, G. H. 1980. Synopsis of biological data on the green turtle in the Hawaiian Islands. NOAA Tech. Memo. NMFS. NOAA-TM-NMFS-SWFC-7.
Balazs, G. H. 1982. Status of sea turtles in the Central Pacific Ocean. Pages 243-252 in Bjorndahl, K. A., editor. Biology and conservation of sea turtles. Smithsonian Institution Press, Washington, D.C. *Copyright date; 1981 on title page.
Bjorndal, K. A., editor. 1982. Biology and conservation of sea turtles. Smithsonian Institution Press, Washington, D.C. 583 pp.
Bowen, B. W., et al. 1992. Global population structure and natural history of the green turtle (Chelonia mydas) in terms of matriarchal phylogeny. Evolution 46:865-881.
Collazo, J. A., R. Boulon, Jr., and T. L. Tallevast. 1992. Abundance and growth patterns of Chelonia mydas in Culebra, Puerto Rico. Journal of Herpetology 26:293-300.
Committee on Sea Turtle Conservation (CSTC), National Research Council (U.S.). 1990. Decline of the Sea Turtles: Causes and Prevention. National Academy Press, Washington, D.C. xv + 259 pp.
Conant, R. and J. T. Collins. 1991. A field guide to reptiles and amphibians: eastern and central North America. Third edition. Houghton Mifflin Co., Boston, Massachusetts. 450 pp.
Dodd, C. K., Jr. 1981. Nesting of the green turtle, Chelonia mydas (L.), in Florida: historic review and present trends. Brimleyana 7:39-54.
Eckert, K.L., S.A. Eckert, T.W. Adams, and A.D. Tucker. 1989. Inter-nesting migrations by leatherback sea turtles (Dermochelys coriacea) in the West Indies. Herpetologica 45:190-194.
Ehrhart, L. M., and B. E. Witherington. 1992. Green turtle Chelonia mydas (Linnaeus). Pages 90-94 in P. E. Moler, editor. Rare and endangered biota of Florida. Vol. III. Amphibians and reptiles. Univ. Press of Florida.
Ernst, C. H., and R. W. Barbour. 1972. Turtles of the United States. Univ. Press of Kentucky, Lexington. x + 347 pp.
Ernst, C. H., and R. W. Barbour. 1989a. Turtles of the world. Smithsonian Institution Press, Washington, D.C. xii + 313 pp.
Ernst, C. H., R. W. Barbour, and J. E. Lovich. 1994. Turtles of the United States and Canada. Smithsonian Institution Press, Washington, D.C. xxxviii + 578 pp.
Frazer, N. B. 1992. Sea turtle conservation and halfway technology. Conservation Biology 6:179-184.
Frazer, N. B., and L. M. Ehrhart. 1985. Preliminary growth models for green, Chelonia mydas, and loggerhead, Caretta caretta, turtles in the wild. Copeia 1985:73-79.
Fritts, T. H., W. Hoffman, and M. A. McGehee. 1983. The distribution and abundance of marine turtles in the Gulf of Mexico and nearby Atlantic waters. J. Herpetology 17:327-344.
Green, D. 1993. Growth rates of wild immature green turtles in the Galapagos Islands, Ecuador. J. Herpetology 27:338-341.
Groombridge, B., and R. Luxmoore. 1989. The green turtle and hawksbill (Reptilia: Cheloniidae): world status, exploitation and trade. Secretariat of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, Lausanne, Switzerland. 601 pp.
Hirth, H. F. 1980. Chelonia mydas. Cat. Am. Amph. Rep. 249.1-249.4.
Iverson, J. B. 1991c. Patterns of survivorship in turtles (order Testudines). Canadian J. Zoology 69:385-391.
King, F. W., and R. L. Burke, editors. 1989. Crocodilian, tuatara, and turtle species of the world: a taxonomic and geographic reference. Association of Systematics Collections, Washington, D.C. 216 pp.
Limpus, C. J., E. Gyuris, and J. D. Miller. 1988. Reassessment of the taxonomic status of the sea turtle genus Natator (McCulloch 1908 with a redescription of the genus and species. Trans. Royal Society S. Australia 112(1/2):1-10.
Losey, G. S., G. H. Balazs, and L. A. Privitera. 1994. Cleaning symbiosis between the wrasse, Thalassoma duperry, and the green turtle, Chelonia mydas. Copeia 1994:684-690.
Luxmoore, R., and J. Canin. 1985. International trade in raw sea turtle shell. IUCN Wildlife Trade Monitoring Unit, Traffic Bulletin 7(2):30-39.
Mack, D., N. Duplaix, and S. Wells. 1982. Sea turtles, animals of divisible parts: international trade in sea turtle products. Pages 545-563 in Bjorndahl, K. A., editor.Biology and conservation of sea turtles. Smithsonian Institution.
Marine Turtle Recovery Team. 1984. Recovery plan for marine turtles (loggerhead turtle, green turtle, leatherbackturtle, hawksbill turtle, and Kemp's ridley turtle). Natl. Mar. Fish. Serv. and U.S. Fish and Wildife Service 363 pp.
Matthews, J.R. and C.J. Moseley (eds.). 1990. The Official World Wildlife Fund Guide to Endangered Species of North America. Volume 1. Plants, Mammals. xxiii + pp 1-560 + 33 pp. appendix + 6 pp. glossary + 16 pp. index. Volume 2. Birds, Reptiles, Amphibians, Fishes, Mussels, Crustaceans, Snails, Insects, and Arachnids. xiii + pp. 561-1180. Beacham Publications, Inc., Washington, D.C.
McKeown, S. 1978. Hawaiian reptiles and amphibians. Oriental Pub. Co., Honolulu. 80 pp.
Meylan, A. B., B. W. Bowden, and J. C. Avise. 1990. A genetic test of the natal homing versus social facilitation models for green turtle migration. Science 248:724-727.
Mitchell, J. C. 1991. Amphibians and reptiles. Pages 411-76 in K. Terwilliger (coordinator). Virginia's Endangered Species: Proceedings of a Symposium. McDonald and Woodward Publishing Company, Blacksburg, Virginia.
Morreale, S. J., and E. A. Standora. No date. Occurrence, movement and behavior of the Kemp's ridley and other sea turtles in New York waters. Final Report, April 1988 - March 1993. Okeanos Ocean Research Foundation and Return a Gift to Wildlife Program (New York Department of Environmental Conservation). 70 pp.
Mortimer, J. A., and K. M. Porter. 1989. Reproductive homing and internesting behavior of the green turtle (Chelonia mydas) at Ascension Island, South Atlantic Ocean. Copeia 1989:962-977.
Mrosovsky, N. 1983. Conserving sea turtles. British Herpetological Society. 176 pp.
National Marine Fisheries Service (NMFS) and U.S. Fish and Wildlife Service (USFWS). 1995. Status reviews for sea turtles listed under the Endangered Species Act of 1973. National Marine Fisheries Service, Silver Spring, Maryland. vi + 139 pp.
National Marine Fisheries Service (NMFS). 1993d. Sea turtle conservation; shrimp trawling requirements. Federal Register 58(158):43820-. 18 August 1993.
National Marine Fisheries Service (NMFS). 1993e. Sea turtle conservation; shrimp trawling requirements. Federal Register 58(181):48975-48978. 21 September 1993.
Niethammer, K. R., G. H. Balazs, J. S. Hatfield, G. L. Nakai, and J. L. Megyesi. 1997. Reproductive biology of the green turtle (Chelonia mydas) at Tern Island, French Frigate Shoals, Hawai`i. Pacific Science 51:36-47.
Seminoff, J. A., J. Alvarado, C. Delgado, J. L. Lopez, and G. Hoeffer. 2002. First direct evidence of migration by an east Pacific green seaturtle from Michoacan, Mexico to a feeding ground on the Sonoran coast of the Gulf of California. Southwestern Naturalist 47:314-316.
The Reptiles of British Columbia: Pacific Green Turtle, Chelonia mydas agassizi. 2004. Univ. Coll. of the Cariboo, and B.C. Minist. Water, Land and Air Prot. Online. Available: http://www.bcreptiles.ca/turtles/pacificgreen.htm
Tuato`o-Bartley, N., T. E. Morrell, and P. Craig. 1993. Status of sea turtles in American Samoa in 1991. Pacific Science 47(3):215-221.
U.S. Fish and Wildlife Service (USFWS). 1980. Selected vertebrate endangered species of the seacoast of the United States-- green sea turtle. FWS/OBS-80/01.13.
U.S. Fish and Wildlife Service (USFWS). 1990. Endangered and threatened species recovery program: report to Congress. 406 pp.
Van Meter, V. B. 1983. Florida's sea turtles. Florida Power & Light Company, Miami. 46 pp.
Whittow, G. C. and G. H. Balazs. 1982. Basking behavior of the Hawaiian green turtle (Chelonia mydas). Pacific Science 36(2):129-139.
Witherington, B. E. 1992. Behavioral responses of nesting sea turtles to artificial lighting. Herpetologica 48:31-39.
Witherington, B. E., and L. M. Ehrhart. 1989. Hypothermic stunning and mortality of marine turtles in the Indian River Lagoon System, Florida. Copeia 1989:696-703.
Zangerl, R., L. P. Hendrickson, and J. R. Hendrickson. 1988. A redescription of the Australian flatback sea turtle, Natator depressus. Bishop Museum Bull. Zoology 1:1-69.
 

Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.

Suggested Citation:

B.C. Conservation Data Centre. 2009. Species Summary: Chelonia mydas. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Nov 13, 2026).