About the Species
The green turtle is one of the largest hard-shelled sea turtles. They are unique among sea turtles in that they are herbivores, eating mostly seagrasses and algae. This diet is what gives their cartilage and fat a greenish color (not their shells), which is where their name comes from.
Green turtles live all over the world, nest in over 80 countries, and live in the coastal areas of more than 140 countries.
Today, all green turtle populations are listed as either endangered or threatened under the Endangered Species Act. The primary threats facing green turtles are bycatch in commercial and recreational fishing gear, direct killing of turtles and harvest of eggs, vessel strikes, loss and alteration of nesting habitat, degradation and loss of foraging habitat, and entanglement in or ingestion of marine debris. While many countries prohibit the killing of green sea turtles (including the the United States), in other areas, the killing of turtles for their meat and collection of eggs continues today. Illegal fisheries also operate to supply shells to the wildlife trafficking trade. In addition, rising sea levels and an increase in the frequency and severity of storm events are likely to inundate some nesting beaches.
NOAA Fisheries and our partners are dedicated to protecting and recovering green turtle populations worldwide. We use a variety of innovative techniques to study, protect, and recover these endangered animals. We engage our partners as we develop measures and recovery plans that foster the conservation and recovery of green sea turtles and their habitats.
In the United States, nesting green sea turtles are primarily found in the Hawaiian Islands, U.S. Pacific Island territories (Guam, the Commonwealth of the Northern Mariana Islands, and American Samoa), Puerto Rico, the Virgin Islands, and the East Coast of Florida. Lower levels of nesting are found in Georgia, South Carolina, and North Carolina. Juveniles are prevalent in all of these areas, and also coastal areas of the Gulf of Mexico.
Population trends of green turtles vary among regions and nesting populations. For instance, the Hawaiian green turtle population (i.e., the Central North Pacific distinct population segment) has been increasing at a rate of 5 percent per year over the past 2 decades. In addition, nesting populations of green turtles in Florida and on the Pacific coast of Mexico are also increasing due to successful and sustained conservation efforts. In 2016, these populations were identified as distinct population segments and classified as “threatened” under the ESA.
In contrast, the Central South Pacific and Central West Pacific populations were classified as “endangered” populations due to their depleted status and continuing vulnerability.
The two largest green turtle nesting populations in the world are found at:
Tortuguero on the Caribbean coast of Costa Rica—22,500 females nest per season (on average).
Raine Island on the Great Barrier Reef in Australia—18,000 females nest per season (on average).
The 2015 ESA status review of the green sea turtle provides additional information on population trends.
- Central South Pacific DPS
- Central West Pacific DPS
ESA Endangered - Foreign
- Mediterranean DPS
- Central North Pacific DPS
- East Pacific DPS
- North Atlantic DPS
- South Atlantic DPS
ESA Threatened - Foreign
- East Indian-West Pacific DPS
- North Indian DPS
- Southwest Indian DPS
- Southwest Pacific DPS
CITES Appendix I
- Throughout Its Range
Green turtles are the largest of all the hard-shelled sea turtles, but have a comparatively small head. A typical adult is 3 to 4 feet long and weighs 300 to 350 pounds. They have dark brown or black shells and a much lighter, yellow underside. Their shells have five scutes (bony plates) running down the middle and four scutes on each side. Another distinct characteristic of the green turtle is their two large scales located between the eyes.
Behavior and Diet
Like other sea turtles, green turtles make long-distance migrations from their feeding areas to nesting beaches in the tropics and sub-tropics.
After settling from their pelagic developmental phase (lasting about 5 to 7 years), into their coastal habitats, green turtles shift to being primarily herbivores. Their diet mainly consists of algae and seagrasses, though they may also forage on sponges and other invertebrates. The East Pacific green turtle tends to eat more animal prey than other populations. Prior to recruiting to nearshore foraging areas, early-stage juveniles forage on plant and animal life found in pelagic drift communities (such as pelagic Sargassum communities).
Where They Live
Adult and juvenile green turtles live are generally found nearshore as well as in bays and lagoons, on reefs, and especially in areas with seagrass beds.
Adults migrate from foraging areas to nesting beaches and may travel hundreds or thousands of kilometers each way. After emerging from the nest, hatchlings swim to offshore areas, where they live for several years. Once the juveniles reach a certain age/size range, they leave the open ocean habitat and travel to nearshore foraging grounds.
In U.S. Atlantic and Gulf of Mexico waters, green turtles are found in inshore and nearshore waters from Texas to Massachusetts, the U.S. Virgin Islands, and Puerto Rico. Important feeding areas in Florida include the Indian River Lagoon, the Florida Keys, Florida Bay, Homosassa, Crystal River, Cedar Key, and St. Joseph Bay.
In the eastern North Pacific, green turtles have been sighted from Baja California to southern Alaska, but most commonly occur from San Diego south.
In the Pacific, green turtles occur around almost all tropical islands, including the State of Hawaii, and U.S. territories of American Samoa, Guam, and the Commonwealth of the Northern Mariana Islands. The majority of adult green turtles that feed throughout the main Hawaiian Islands migrate to French Frigate Shoals in the Northwest Hawaiian Islands to nest.
Lifespan & Reproduction
The lifespan for green turtles is currently unknown but thought to be at least 60 to 70 years.
Green turtles become sexually mature at 25 to 35 years, and some may be as old as 40 before they reproduce. Their reproductive lifespan is uncertain, but some individuals have been observed nesting for at least 38 years. We have not been studying green turtles long enough to know how long individuals remain reproductively active.
In the United States, the breeding season occurs in late spring and early summer. Males mate with females on foraging grounds, along migratory pathways, and off nesting beaches. Adult males can breed every year, but females migrate from their foraging areas to nest every 2 to 5 years.
Female green sea turtles lay about 100 eggs per nest and will nest every two weeks over several months before leaving the nesting area and returning to their foraging grounds.
After about 2 months, the eggs hatch and the hatchlings make their way to the water. The newly hatched green sea turtles are susceptible to nighttime predators; however, hatchlings emerge at night when fewer predators are active.They are particularly threatened by artificial beachfront lighting which can disorient them and prevent them from finding the sea. Hatchlings orient themselves towards the brightest horizon. On undeveloped beaches, this is toward the open horizon over the ocean. However, in areas with artificial lighting hatchlings crawl towards bright lights instead of the ocean.
Bycatch in Fishing Gear
A primary threat to sea turtles is their unintended capture in fishing gear which can drown turtles due to forced submergence or cause injuries that lead to death or debilitation (for example, swallowing hooks). The term for this unintended capture is bycatch. Sea turtle bycatch is a worldwide problem.
Intentional Killing of Turtles and Harvest of Eggs
The main cause of the historical, worldwide decline of the green turtle is long-term harvest of eggs and the intentional killing of green sea turtles on nesting beaches and feeding grounds. Killing turtles and harvesting eggs remains legal in some countries but this can disrupt regional efforts to recover this species.
Loss and Degradation of Nesting Habitat
Coastal development and rising seas from climate change are leading to the loss of critical nesting beach habitat for green sea turtles. Shoreline hardening or armoring (e.g., seawalls) can result in the complete loss of dry sand suitable for successful nesting. Artificial lighting on and near nesting beaches can deter nesting females from coming ashore to nest and can disorient hatchlings trying to find the sea after emerging from their nests.
Ocean Pollution/Marine Debris
Marine turtles may die after ingesting fishing line, balloons, plastic bags, plastic pieces, or other plastic debris which they can mistake for food. They may also become entangled in this or other marine debris, such as lost or discarded fishing gear, and can be killed or seriously injured.
Fibropapillomatosis is a disease that causes tumors externally on the exposed soft tissues of green turtles and internally on vital organs. These tumors can significantly affect a turtles’ quality of life and can lead to death. For example, if a tumor blocks a turtle’s mouth or eyes, it may not be able to feed properly and/or may be unable to effectively avoid predators. The disease is most prevalent in green turtles and some evidence has linked the disease prevalence to degraded marine habitats.
Green turtles are protected under the Endangered Species Act. Eleven populations are listed as endangered or threatened under the Act. This means that the green turtle is in danger of extinction, now or in the foreseeable future, throughout all or a significant portion of its range. NOAA Fisheries is working to protect this species in many ways, with the goal that populations will increase worldwide.
In the United States, NOAA Fisheries and the U.S. Fish and Wildlife Service have joint jurisdiction for sea turtles, with NOAA having the lead in the marine environment and U.S. FWS having the lead on the nesting beaches. Both federal agencies, along with many state agencies and international partners, have issued regulations to eliminate or reduce threats to sea turtles, while working together to recover them.
Recovery Planning and Implementation
To help identify and guide the protection, conservation, and recovery of sea turtles, the ESA requires NOAA Fisheries and U.S. FWS to develop and implement recovery plans, in close coordination with stakeholders, for each listed sea turtle species. Recovery plans provide a blueprint for conservation of the species and measurable criteria to gauge progress toward recovery.
The major recovery actions for green sea turtles include:
Protecting turtles on nesting beaches.
Protecting nesting and foraging habitats.
Reducing bycatch in commercial and recreational fisheries.
Reducing the effects of entanglement and ingestion of marine debris.
Studying the impact of diseases on turtles.
Working with partners internationally to protect turtles in all life-stages in foreign waters.
Supporting research and conservation projects consistent with Recovery Plan priorities.
Three recovery plans have been developed to recover and protect green turtle populations. Each is focused on the unique needs of turtles in the various regions. Recovery Plans are periodically reviewed and updated as necessary. Current recovery plans for green turtles:
The highly migratory behavior of sea turtles makes them shared resources among many nations, so conservation efforts for sea turtle populations in one country may be jeopardized by activities in another. This means that protecting sea turtles on U.S. nesting beaches and in U.S. waters alone is not enough to ensure the continued existence of the species. Learn more about international conservation efforts below.
NOAA Fisheries is working to minimize effects from human activities that are detrimental to the recovery of green sea turtle populations in the United States and internationally. Together with our partners, we undertake numerous activities to support the goals of the green turtle recovery plans, with the ultimate goal to delist the species.
Efforts to conserve green turtles include:
Protecting habitat and designating critical habitat.
Rescue, disentanglement, and rehabilitation.
Eliminating the harvest of turtles and their eggs.
Eliminating the harassment of turtles on nesting beaches through education and enforcement.
Consulting with federal agencies to ensure their activities are not likely to jeopardize the continued existence of listed species.
Conservation efforts have been successful. The protection of nesting beaches, reduction of bycatch in fisheries, and prohibitions on the direct harvest of sea turtles and their eggs, have led to increasing numbers of green turtles nesting in Florida, along the Pacific coast of Mexico, and in Hawaii. Because of successful efforts, NOAA Fisheries and the U.S. FWS revised the listing for green sea turtles under the ESA in 2016, reclassifying turtles originating from two breeding populations (Florida and Pacific coast of Mexico) from endangered to threatened status.
While threats remain for green sea turtles globally, the reclassification of green sea turtles in Florida and Mexico shows how domestic and international partnerships are making a real difference for some of our planet’s most imperiled marine species.
Once a species is listed under the ESA, NOAA Fisheries evaluates and identifies whether any areas meet the definition of critical habitat. Those areas may be designated as critical habitat through a rulemaking process.
The designation of an area as critical habitat does not create a closed area, marine protected area, refuge, wilderness reserve, preservation, or other conservation area; nor does the designation affect land ownership. Federal agencies that undertake, fund, or permit activities that may affect these designated critical habitat areas are required to consult with NOAA Fisheries to ensure that their actions do not adversely modify or destroy designated critical habitat.
In 1998, it was determined that habitat loss and degradation of seagrass beds were primary factors slowing the recovery of green turtles in the Caribbean. As a result, NOAA Fisheries and the U.S. Fish and Wildlife Service designated critical habitat for green turtles to include the coastal waters around Culebra Island, Puerto Rico. The Culebra seagrass beds provide important foraging habitat for sea turtles, as well as other many other marine species.
We are in the process of identifying other potential critical habitat, which will be proposed in a future rulemaking.
To reduce the bycatch of sea turtles in commercial fisheries, we have enacted regulations to reduce bycatch in certain U.S. commercial fishing gears (gillnets, longlines, pound nets, and trawls) that unintentionally capture sea turtles. Measures include:
Changes to fishing practices.
In the United States, NOAA Fisheries has worked closely with the shrimp trawl fishing industry to develop turtle excluder devices to reduce the mortality of sea turtles incidentally captured in shrimp trawl gear. These devices (commonly called TEDs) are large enough to exclude even the largest sea turtles and are required for use in shrimp otter trawl nets.
Since 1989, the United States has prohibited the importation of shrimp harvested in a manner that adversely affects sea turtles. The import ban does not apply to nations that have adopted sea turtle protection programs comparable to that of the United States. (i.e., require and enforce the use of TEDs) or to nations where bycatch in shrimp fisheries does not present a threat to sea turtles (for example, nations that fish for shrimp in areas where sea turtles do not occur). The U.S. Department of State is the principal agency of this law, while we serve as technical advisor. We provide extensive TED training throughout the world.
Additionally, we have been involved in cooperative gear research projects, implementation of changes to gear and fishing practices, and safe handling protocols designed to reduce sea turtle bycatch and mortality in the Gulf of Mexico and Atlantic pelagic longline fisheries, the American Samoa and Hawaii-based longline fisheries, the Atlantic sea scallop dredge fishery, the Chesapeake Bay pound net fishery, and non-shrimp trawl fisheries in the Atlantic and Gulf of Mexico.
Utilizing Fisheries Observers
Bycatch in fishing gear is the primary anthropogenic source of sea turtle injury and mortality in U.S. waters. The most effective way to learn about sea turtle-fishery interactions is to place observers aboard fishing vessels. Under the ESA, NOAA Fisheries identifies commercial and/or recreational fisheries in the Atlantic Ocean, Gulf of Mexico, and Pacific Ocean that are required to have observers to record sea turtle interactions. The purpose of observing these fisheries is to:
Learn more about sea turtle interactions.
Evaluate measures to reduce fisheries impacts/bycatch of protected sea turtles.
Determine whether additional measures may be necessary to prevent sea turtle bycatch.
NOAA Fisheries determines which fisheries are required to carry observers to monitor potential interactions with sea turtles through an annual determination. Observers may also be placed on fisheries through our authorities under the Magnuson-Stevens Act.
Responding to Strandings and Entanglements
A stranded sea turtle is one that is found on land or in the water dead, injured, sick, or exhibiting usual behavior. One of the most well-known examples of mass strandings is when cold-stunned sea turtles strand during winter months on the Atlantic and Gulf coasts. During these events, thousands of turtles may require care.
The Sea Turtle Stranding and Salvage Network was established in response to the need to better understand the threats sea turtles face in the marine environment, to provide aid to stranded sea turtles, and to salvage dead sea turtles that may be useful for scientific and educational purposes. The network collects information on and documents strandings of marine turtles along the U.S. Gulf of Mexico and Atlantic coasts and includes federal, state, and private partners. This information is compiled into a centralized database.
NOAA’s Pacific Islands Fisheries Science Center’s Marine Turtle Biology and Assessment Program rehabilitates and studies stranded sea turtles throughout the Hawaiian Islands. Other state and local organizations respond to sea turtle strandings on the U.S. West Coast.
The actions taken by stranding network participants improve the survivability of sick, injured, and entangled turtles while also helping scientists and managers expand their knowledge about threats to sea turtles and causes of mortality.
Participating in International Conservation Efforts
The conservation and recovery of sea turtles requires international cooperation and agreements to ensure the survival of these highly migratory animals. We have a broad national and international program and work closely with partners under two international environmental agreements that deal exclusively with sea turtle conservation:
Additional international treaties and agreements include:
Convention on International Trade in Endangered Species (CITES) - listed in Appendix I, which prohibits international trade of wild flora and fauna.
Cartagena Convention - protected under Annex II of the Specially Protected Areas and Wildlife (SPAW) Protocol.
The green sea turtle was first listed under the ESA in 1978. In April 2016, we revised this by listing eight distinct population segments (DPS) as threatened and three DPS as endangered. The 2015 ESA status review provided the scientific basis to revise the ESA listings.
In 1992, we finalized regulations to require turtle excluder devices in shrimp trawl fisheries to reduce interactions between turtles and trawl gear. Since then, we have changed these regulations as new information became available on increasing the efficiency of TEDs. For example, larger TEDs are now required to exclude larger turtles.
We have implemented additional measures to reduce sea turtle interactions in fisheries through regulations and permits under both the ESA and Magnuson-Stevens Act including the use of large circle hooks in longline fisheries, time and area closures for gillnets, and modifications to pound net leaders.
See all regulations to protect sea turtles.
Regulatory Actions & Documents
- Proposed Rule; Request for Comments; Notice of Public Hearings (81 FR 91097)
- Notice of Intent to Prepare EIS (81 FR 13772, 03/15/16)
NOAA Fisheries conducts various research activities on the biology, behavior, and ecology of the green sea turtle. The results of this research are used to inform management decisions and enhance recovery efforts for endangered and threatened green turtle populations.
Turtle population assessments ideally include information on the species’ abundance and distribution, life history, and human impacts. This information can help us evaluate the effectiveness of conservation and recovery measures, and can help guide actions to enhance recovery. To estimate population abundance, researchers conduct aerial and vessel-based surveys of selected areas and capture and mark turtles in the water and on beaches. We also incorporate data collected on nesting beaches, via stranding networks, and from fisheries observer programs. Other information that informs sea turtle population assessments includes population structure (genetic analyses), age to maturity, survivorship of the various life stages (e.g., hatchling, juvenile, adult), foraging and reproductive behavior, movement and distribution, and habitat studies.
Satellite Tagging and Tracking Studies
Satellite telemetry allows researchers to track sea turtles as they swim from place to place. These satellite tags are designed and attached in a manner that minimizes disturbance to the turtle. The tags will eventually fall off. The data help us understand migration patterns, identify feeding areas, and identify where turtles overlap with their primary threats (e.g., fishing gear).
Research to Reduce Bycatch in Fishing Gear
We observe fisheries to understand the amount of sea turtle bycatch in various fisheries and the ways in which leatherbacks interact with fishing gear. We develop, evaluate, and modify fishing gear and/or fishing practices to reduce sea turtle bycatch while at the same time retaining a sustainable fish catch. These efforts include TED development for trawl fisheries, use of circle hooks and certain bait types in longline fisheries, time and area closures for gillnets, and modifications to pound net leaders.
Sea Turtle Genetics
NOAA Fisheries’ National Sea Turtle Molecular Genetics Center serves as a worldwide central depository for sea turtle tissue and DNA samples and constitutes a major area of research supporting sea turtle conservation. For example, a turtle’s unique genetic “fingerprint” can be used to determine its nesting population and home nesting beach.
Life history studies include gathering information on such things as migration patterns, where turtles nest and forage, growth rates, age to maturity, and sex ratios. This information is important in understanding key biological parameters that influence population trends and inform conservation status.
Recent Science Blogs
Report of the Technical Expert Workshop: Developing Recommendations for Field Response, Captive Management, and Rehabilitation of Sea Turtles with Fibropapillomatosis
NOAA and USFWS hosted a workshop in St. Petersburg, Florida on September 6, 2017 to seek input on…
This study investigated the impacts Florida artificial reefs may have on sea turtle populations,…
Biological Opinion on the Issuance of Permit No. 20315 for Scientific Research on Sea Turtles in the United States Virgin Islands
The permit application is to continue a project studying green (South Atlantic distinct population…
Biological Opinion on the Issuance of Permit No. 19697 for Scientific Research on Sea Turtles in the Coastal Waters of Puerto Rico
The Permits Division proposes to issue scientific research Permit No. 19697 for the measuring,…
Impact of Exceptional Growth Rates on Estimations of Life-Stage Duration in Hawaiian Green Sea Turtles
New information on growth spurts and the potential impact on estimates of lifetime growth rate and…