Green sea turtles are one of
the world’s largest species of turtle, weighing around 65-130kg and measuring
between 1-1.2m long.
WHY THEY MATTER?
These turtles are believed to
improve the health of seagrass beds and associated microhabitats. They will
graze the beds, taking off the tops of leaf blades, while avoiding the roots.
The seagrass will grow healthier and faster with a daily trim! Learn about
their diet.
Green turtles graze on
seagrasses and algae, which maintains the seagrass beds and makes them more
productive (much like mowing the lawn to keep it healthy). Seagrass consumed by
green turtles is quickly digested and becomes available as recycled nutrients
to the many species of plants and animals that live in the sea grass ecosystem.
Seagrass beds also function as nurseries for several species of invertebrates
and fish, many of which are of considerable value to commercial fisheries and
therefore important to human food security.
DID YOU KNOW?
1. Green sea turtles aren't
named for the color of their shells or carapaces; they're named for the
greenish hue of their skin. Their shells are normally brown, dark olive, gray
or black, depending on their habitat. Their shells are smooth and heart shaped.
The underside of the shell, called the plastron, is a yellowish-white color.
2. There are two types of
green turtles — scientists debate whether they are subspecies or separate
species — the Atlantic green turtle, generally found off the coasts of Europe
and North America, and the Eastern Pacific green turtle, which lives in coastal
waters from Alaska to Chile. They can live up to 80 years.
3. Adults are 3 to 4 feet in
carapace length (83 – 114 cm). The green turtle is the largest of the
Cheloniidae family. The largest green turtle ever found was 5 feet (152 cm) in
length and 871 pounds (395 kg). Adults weigh between 240 and 420 pounds (110 –
190 kg).
4. Unlike most other sea
turtles, adult green turtles are herbivorous, and prefer sea grasses and algae.
Juvenile green turtles are omnivores, and eat invertebrates like crabs,
jellyfish and sponges. Diet changes significantly during its life. When less
than 8 to 10 inches in length eat worms, young crustaceans, aquatic insects,
grasses and algae. Once green turtles reach 8 to 10 inches in length, they
mostly eat sea grass and algae, the only sea turtle that is strictly
herbivorous as an adult. Their jaws are finely serrated which aids them in
tearing vegetation.
5. They have a strong,
tear-drop shape shell, called a ‘carapace’, which covers most of their body,
except for their head and four flippers. Their carapace can include shades of
different colours, including dark brown, green, olive, yellow and black. The
green turtle is one of the largest sea turtles and the only herbivore among the
different species.
6. Most sea turtles warm themselves
by swimming close to the surface of shallow waters, but Eastern Pacific green
turtles are known for lumbering onto land to bask in the sun. If you spot a
green sea turtle on the beach, it's important to give the animal some space. In
Hawaii, the green sea turtle is referred to as honu and is revered as a symbol
of good luck and longevity.
7. Green turtles’ nest at
intervals of about every 2 years, with wide year-to-year fluctuations in
numbers of nesting females. Nests between 3 to 5 times per season. Lays an
average of 115 eggs in each nest, with the eggs incubating for about 60 days.
8. Green turtles reach sexual
maturity between 20 years and 50 years old. They migrate long distances from
their feeding sites to their nesting grounds, which for females is the beach
where they were born. In late spring and early summer, male green sea turtles
arrive first at the breeding grounds — normally in shallow waters close to the
sandy beach where the females lay their eggs — and wait for the females to come.
While males are capable of mating every year, females’ mate only every two to
four years. In the U.S., females lay their eggs in the southeastern U.S.,
Texas, Puerto Rico, the Virgin Islands and Hawaii.
9. The females crawl out on
beaches and lay their eggs during the night. When laying their eggs, they dig a
pit in the sand with their flippers, fill it with their clutch of 100 to 200
eggs, cover the pit and return to the sea. The eggs hatch after about two
months. The hatchlings have to run a gauntlet of predators, including crabs and
seagulls, as they make their way into the sea. If they can survive this
dangerous time, and other life-threatening hazards, green sea turtles can live
80 to 100 years.
10. This species can be found
in the sub-tropics and tropics worldwide, with major nesting beaches in
Tortuguero (Costa Rica), Oman, Florida, and Raine Island (Australia) where
thousands of turtles nest each night during peak nesting season. They are also
found nesting on French Frigate Shoals in the Northwestern Hawaiian Islands,
Guam, American Samoa, Suriname, Georgia, South Carolina, North Carolina, Puerto
Rico, and the US Virgin Islands. Population Estimate*: Between 85,000 and
90,000 nesting females.
11. Status: U.S. – Down listed
as Threatened (likely to become endangered, in danger of extinction, within the
foreseeable future) under the U.S. Federal Endangered Species Act in April
2016. Originally listed as Endangered in 1978.
International – Listed as Endangered (facing a very high risk of
extinction in the wild in the near future) by the International Union for
Conservation of Nature and Natural Resources in 1982.
THREATS
Green turtles are listed as an
endangered species. Despite this, they are still killed for their meat and
eggs. Their numbers are also reduced by boat propeller accidents,
fishnet-caused drowning, and the destruction of their nesting grounds by human
encroachment.
Fisheries Bycatch
Worldwide, hundreds of
thousands of sea turtles a year are accidentally caught in shrimp trawl nets,
on longline hooks and in fishing gillnets. Sea turtles need to reach the
surface to breathe, and therefore many drown once caught. Known as bycatch, it
is a serious hazard for green turtles. As fishing activity expands, this threat
is more of a problem.
Habitat Loss
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. Green turtle feeding grounds such as
seagrass beds are also at risk from coastal development onshore, which leads to
pollution and sedimentation in the nearby waters.
Plastic Bags
Unfortunately, plastic bags
are doing big harm to their food cycle. Plastic has only been mass-produced
since the 1940s, but it’s having a devastating impact on sea turtles. Many of
us are doing our part to reduce plastic pollution by recycling and reducing
single-use items, but governments must also step up to take accountability and
end this pollution epidemic.
Fibropapilloma (also known as
FP) is a disease associated with lesions and rapid tumor growth on the eyes,
mouth, and soft-skin areas, as well as internal organs. FP, believed to be
connected to ocean pollution, has greatly affected their populations,
especially in Florida and Hawaii, but also the Caribbean and Australia.
Light Pollution
Light pollution near beach
nesting sites poses a risk to sea turtle hatchlings, which may get confused and
crawl toward the light instead of travelling to the ocean. Green sea turtles and
their food also face over-hunting, including for use in sea turtle soup.
Over-harvesting and Illegal
Trade
Worldwide, the green turtle
continues to be hunted and its eggs harvested. Much of that is for human consumption,
but trade of turtle parts remains a profitable business. Tens of thousands of
green turtles are harvested every year, particularly in parts of Asia and the
Western Pacific. Along the Eastern Pacific coast of Mexico, despite complete
protection, green turtles are still at risk from exploitation. In West Africa,
sea turtles are killed for use in medicine and some traditional ceremonies.
HOW YOU CAN HELP
Today, green sea turtles are
classified as an endangered species and we need to do all we can to protect
them! To find out how you can help, swim over to wwf.panda.org
1.
ADOPT A TURTLE
Make a symbolic turtle
adoption to help save some of the world's most endangered animals from
extinction and support WWF's conservation efforts.
2.
TAKE ACTION
Join us to make change. Speak
up for species and places through WWF's Action Center.
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