Status: Endangered in Florida
A medium sized sea turtle with a brownish carapace containing radiating patterns and a smaller head compared to other sea turtles. The adult can reach a length of 120 cm and weigh as much as 350 pounds. The turtle’s carapace (shell) ranges in color from black to green with irregular patterns. The plastron remains yellowish white throughout life. The common name is derived from the greenish color of its fat. Economically, green turtles are the most important reptile in the world. Its flesh and eggs serve as an important source of protein in many third world nations.
Habitat and Distribution:
The green turtle ranges worldwide and can be found in sub-tropical and tropical waters throughout the Atlantic, Pacific, and Indian oceans. Juveniles and adults of the Atlantic green turtle are frequently found in Florida waters, especially in areas abundant in sea grasses (on which they feed). Hatchling green turtles spend an undetermined amount of time in the open ocean.
Life History and Ecology:
Nesting occurs year round in tropical waters, but in Florida the nesting period is from April to August. The green turtle’s nesting frequency is based on a two, three, or four year interval, but an individual may lay up to 7 clutches at 14 day intervals. Each nest contains an average of 130 eggs per clutch and will hatch in 55-60 days. The hatchling turtles emerge out of the nest as a group and crawl to the ocean. The turtles may travel long distances and encounter many predators during their lifetime. Maturity is reached in 20-25 years and they may live for up to 60 years.
Basis of Status Classification:
The status of green turtle populations is difficult to determine because of the long generation time and inaccessibility of the early life stages. Overexploitation by man has already caused the extinction of large green turtle populations including those once nesting on Bermuda and Cayman Islands. Green turtles continue to be heavily exploited by man, and degradation of nesting and feeding habitats are impeding the recovery of this species. Nesting appears to be increasing in Florida but this may be as a result of increased monitoring and survey efforts.
The US population of green turtles can be considered for delisting if, over a period of 25 years, the following conditions are met:
- The level of nesting in Florida has increased to an average of 5,000 nests per year for at least 6 years.
- At least 25% of all available nesting beaches is in public ownership and encompasses greater than 50% of the nesting activity.
- A reduction in stage class mortality is reflected in higher counts of individuals on foraging grounds.
- All priority one tasks have been successfully implemented (NMFS and USFWS, 1991).
- Protect and manage nesting habitat
- ensure beach nourishment projects are compatible
- prevent degradation of habitat from erosion control measures (sea walls)
- acquire and ensure long-term protection of important nesting beaches
- remove exotic vegetation on nesting beaches
- prevent degradation and improve water quality of important turtle habitat
- prevent destruction of habitat from fishing gears, vessel anchoring, oil and gas activities, dredging activities
- monitor trends in nesting activity
- reduce effects of artificial lighting
- eliminate poaching and harassment
- determine seasonal green turtle distribution and abundance
- monitor and reduce mortality from commercial and recreational fisheries and from dredging activities
- reduce impacts from entanglement and ingestion of marine debris
Ernst, C, J Lovich and R Barbour. 1994. Turtles of the United States and Canada. Smithsonian Institution Press. Pp. 59-73.
Lutz, P and J Musick. The Biology of Sea Turtles. CRC Press. Boca Raton, Florida. 432 pp.
National Marine Fisheries Service and US Fish and Wildlife Service. 1991. Recovery Plan for US Population of Atlantic Green Turtle. National Marine Fisheries Service, Washington, D.C.
Content updated Date March 4, 2005