Seven different species of sea (or marine) turtles grace our ocean waters, from the shallow seagrass beds of the Indian Ocean, to the colorful reefs of the Coral Triangle and the sandy beaches of the Eastern Pacific. While these highly migratory species periodically come ashore to either bask or nest, sea turtles spend the bulk of their lives in the ocean. WWF's work on sea turtles focuses on five of those species: green, hawksbill, loggerhead, leatherback, and olive ridley.
WWF is committed to stopping the decline of sea turtles and works for the recovery of the species. We work to secure environments in which both turtles and the people that depend upon them can survive.
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Sea turtles are a fundamental link in marine ecosystems. They help maintain the health of seagrass beds and coral reefs that benefit commercially valuable species such as shrimp, lobster, and tuna. Sea turtles are the live representatives of a group of reptiles that have existed on Earth and traveled our seas for the last 100 million years. Turtles have major cultural significance and tourism value. Five of the seven species are found around the world, mainly in tropical and subtropical waters. The remaining two species, though, have relatively restricted ranges: Kemp's ridley is found mainly in the Gulf of Mexico and the flatback turtle around northern Australia and southern Papua New Guinea.
Sea turtles journey between land and sea and swim thousands of ocean miles during their long lifetimes. They wait decades until they can reproduce, returning to the same beaches where they were born to lay their eggs. Females can lay hundreds of eggs in one nesting season, yet few will yield hatchlings that survive their first year of life. Beyond these significant natural challenges, sea turtles face multiple threats caused by humans, such as bycatch in commercial fishing gear, illegal trade, consumption, and climate change.
Sea turtles need to reach the surface to breathe and therefore many drown once caught. Incidental capture by fishing gear is the greatest threat to most sea turtles, especially endangered loggerheads, greens, and leatherbacks. This threat is increasing as fishing activity expands.
Sea turtles continue to be harvested unsustainably both for human consumption and trade of their parts. Turtle meat and eggs are a source of food and income for many people around the world. Some also kill turtles for medicine and religious ceremonies. Tens of thousands of sea turtles are lost this way every year, devastating populations of already endangered greens and hawksbills.
Killing of turtles for both domestic and international markets continues as well. International trade in all sea turtle species and their parts is prohibited under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), a global agreement among governments to regulate or ban international trade in species under threat. Still, illegal trafficking persists.
Sea turtles are dependent on beaches for nesting. Uncontrolled coastal development, vehicle traffic on beaches, and other human activities have directly destroyed or disturbed sea turtle nesting beaches around the world. For example, lights from roads and buildings disorient hatchlings away from the sea, and vehicle traffic on beaches compacts the sand, making it impossible for female turtles to dig nests. Turtle feeding grounds such as coral reefs and seagrass beds are damaged and destroyed by activities onshore, including sedimentation from clearing of land and nutrient run-off from agriculture. Beach restoration projects for protecting seaside buildings have also been found to be harmful, through dredging and sand filling.
Warmer sea surface temperatures can also lead to the loss of important foraging grounds for sea turtles, while increasingly severe storms and sea level rise can destroy critical nesting beaches and damage nests.
WWF works around the world to eliminate sea turtle bycatch from fisheries, reduce the unsustainable harvest and illegal trade in sea turtles, and stem the loss of critical sea turtle habitats. Many of these objectives are achieved by establishing and strengthening protected areas around nesting beaches, raising awareness and promoting ecotourism, lobbying for turtle-friendly fishing practices, and more.
WWF aims to reduce turtle bycatch by working with fisheries to switch to more turtle-friendly fishing hooks ("circle" hooks). We advocate for the use of special turtle excluder devices in nets. WWF has worked with the National Oceanic and Atmospheric Administration (NOAA) to develop lights to reduce the bycatch of turtles in gill nets. These lights have been shown to reduce turtle bycatch by 60%-70%, and we are working to introduce them to fisheries around the world. WWF also tracks turtle movements using satellites to help prevent future interactions between fisheries and turtles and work with fishermen to help them save turtles caught in fishing gear.
WWF works with local communities to reduce turtle harvesting and egg collection. Because exploitation of turtles is often driven by a lack of economic choices, we help develop alternative livelihoods so that local people are no longer dependent on turtle products for income. WWF also supports programs that promote the value of sea turtles. WWF works through TRAFFIC, the wildlife trade monitoring network, to stop the illegal trade of turtle shells, meat, and eggs. We also train and equip local rangers to patrol turtle nesting beaches and protect against poaching.
WWF has been supporting a campaign led by TRAFFIC to combat illegal trade from the Coral Triangle and reduce demand in China. Activities include better training for law enforcement officials in both areas and a public awareness campaign in China, targeting areas where turtle trade is the highest. Radio broadcasts and advocacy events spread the message among local fishermen, souvenir shop owners, and tourists about the problem of turtle trade.
In the western Solomon Islands, WWF supports local rangers on the beaches throughout turtle nesting and hatching seasons to protect against egg harvesting and hunting. The rangers collect important data and inform their communities about laws to protect turtles.
WWF works around the world to establish marine protected areas, ensuring sea turtles have a safe place to nest, feed, and migrate freely. We encourage governments to strengthen legislation on, and provide funding for, sea turtle protection. WWF supports local turtle conservationists in many parts of the world to monitor and patrol turtle nests. These efforts often lead to ecotourism opportunities and offer alternative livelihoods.
WWF studies how sea turtles are being affected by climate change and helps determine the best ways to reduce their vulnerability to changing environmental conditions. We work around the world with communities to monitor and protect nesting beaches, helping turtles be more resilient to the future impacts of climate change. In the Eastern Pacific and Caribbean, we work to raise awareness of the threat of sea level rise on nest sites and the importance of shade for nests.
Satellite telemetry allows researchers to track sea turtles as they swim from place to place. These satellite tags do not harm the turtles in any way and are designed to eventually fall off. The data will tell us where important feeding areas are, help us understand migration patterns and anticipate where turtles may come in contact with fisheries and their gear. These projects include tracking of hawksbill turtles in Malaysia; leatherback turtles in Panama, Suriname, French Guiana, Uruguay, Indonesia, and Gabon; loggerhead turtles in Cape Verde; green turtles in Cambodia; and olive ridley turtles in Australia.
In most species, gender is determined during fertilization. However, the sex of most turtles, alligators, and crocodiles is determined after fertilization. The temperature of the developing eggs is what decides whether the offspring will be male or female. This is called temperature-dependent sex determination, or TSD.
Research shows that if a turtle's eggs incubate below 27.7 Celsius (81.86 Fahrenheit), the turtle hatchlings will be male. If the eggs incubate above 31 Celsius (88.8 Fahrenheit), however, the hatchlings will be female. Temperatures that fluctuate between the two extremes will produce a mix of male and female baby turtles.
Researchers have also noted that the warmer the sand, the higher the ratio of female turtles. As the Earth experiences climate change, increased temperatures could result in skewed and even lethal incubation conditions, which would impact turtle species and other reptiles.
All sea turtle species exhibit TSD type Ia in which, higher temperatures produce female hatchlings and lower temperatures male hatchlings (Standora and Spotila 1985), as opposed to tuataras (TSD type Ib) that produce females at low temperatures (Mitchell et al. 2010) and some freshwater turtles and crocodiles (TSD II) that produce females at both high and low temperatures and males at intermediate temperatures (Ewert et al. 2004).
Nest site selection has been defined as the process of nesting in locations that are not chosen randomly within a given area (Wilson 1998). Because egg development depends on the environmental conditions encountered in the egg chamber, the selection of the nesting site by the mother could influence the nest environment during development. Sea turtles exhibit different selection patterns that can vary among species or locations. For example, Stoneburner and Richardson (1981) found that nest site selection in loggerhead turtles (Caretta caretta) in Florida was related to temperature in the sand. Hawksbill turtles (Eretmochelys imbricata) in Guadeloupe also significantly repeated nest choice with some females preferring to nest in the low-lying vegetation, while others repeatedly nested in the forest border or the forest itself (Kamel 2005). Likewise, leatherback turtles (Dermochelys coriacea) in French Guyana showed a tendency for individuals to nest at particular distances from the water lines (Kamel and Mrosovsky 2004). 2ff7e9595c
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