Sea Turtles are ancient creatures. Some scientists say they are over 110 million years old, while others claim their lineage goes back 140 million years. They were here before the dinosaurs roamed the planet; and yet today, all species are on the IUCN (World Conservation Union) Red List meaning they are facing a high risk of global extinction. The United States Endangered Species Act (ESA) also places sea turtles species as endangered. In addition and unfortunately, scientists believe that leatherback sea turtles could be facing extinction in as little as ten years. Save the Turtles, Inc, stands humbled by these gentle creatures and works towards their survival.

About Sea Turtles

  • Air breathing reptiles, but can spend hours submerged in the ocean. Adult females must return to land in order to lay their eggs. Many species return to the same beach where they were born to lay their eggs.
  • Are found in oceans all over the world, except the Arctic Ocean.
  • May migrate hundreds or thousands of miles. It is believed that they use the earth’s magnetic forces to navigate throughout the oceans.
  • Most prefer open water, but they are also encountered in coastal waters near reefs and estuaries.
  • Are sensitive to smells and sound. They hear through eardrums below their skin.
  • The adult green turtles are unique among sea turtles in that they are herbivorous, feeding primarily on seagrasses and algae. Most sea turtles are mainly carnivores and feed on jellyfish, tunicates (ascidians, sea squirts), sponges (one of a few animals that eat them), soft corals, crabs, squids and fishes.
  • All 7 species of marine turtles are listed under the Endangered Species Act (ESA).

Sea Turtles & Taxonomy: the scientific classification system

Kingdom: Animalia

Phylum: Chordata

Class: Reptilia (includes turtles, snakes, lizards, and crocodiles)

Order: Testudines (includes turtles, tortoises and terrapins). See additional notes below that explain the difference between these categories.

Family: Dermochelyidae: The Leatherback is the only non-extinct species remaining in this family and is distinguished from all other turtles by the semi-flexible “leathery” skin on its outer shell

Cheloniidae: Most scientists group remaining sea turtle species under the family Cheloniidae. These species have shells covered with hard bony plates or scutes

How to Distinguish the Seven Different Species

The outer shell or carapace is the primary feature used in the identification of sea turtle species. The number of scutes on the carapace, their shape, coloring and patterning is specific to each species. Another anatomical feature utilized to distinguish between sea turtles are the prefrontal scales located on the turtle’s head.

There are seven living species of sea turtles (the first name listed is based on their physical characteristics and this common name varies in different counties). The name in parenthesis refers to their scientific taxonomy of species and genus:

Leatherback

Leatherback (Dermochelys coriacea) Leatherbacks are the largest of all sea turtles, the only sea turtle with a leathery soft shell, and unfortunately are the specie that is most in danger of extinction.

Hawksbill

Photo © Caroline Rogers
Hawksbill (Eretmochelys imbricata) The beak-like mouth gives the Hawksbill turtle its name. Unfortunately for the hawksbill, their shell is so beautiful that this turtle is often hunted for its shell.

Loggerhead

Photo © Marco Giuliano/Fondazione Cetacea
Loggerhead (Caretta caretta) Named for their large heads. Known to migrate from Japan to Mexico.

Green Sea

©2005 Robert Van Damn
Green Sea (Chelonia mydas) Largest of all the hard-shelled sea turtles and as an adult, are the only species that are herbivorous.

Kemp’s Ridley

©Cynthia Rubio & NPS
Kemp’s Ridley (Lepidochelys kempii)This species is the smallest of the sea turtles. The name Kemp is used because of the man, Richard M. Kemp, who first described these turtles.

Olive Ridley

© Kedar Gore
Olive Ridley (Lepidochelys olivacea) Most abundant sea turtle and derives its name from the olive coloration of its heart-shaped shell.

Flatback

© Jarrad Sherborne
Flatback (Natator depressa) Only sea turtle that exclusively nests in just one country, Australia. They are so named because of their flat shell.

Sea Turtles are Global

Although each species has their own preference for nesting grounds, migration patterns and diet, they also have similar characteristics and unfortunately share the same threats.

Migration & Navigation

There has been extensive research conducted regarding the sea turtles’ abilities to return to their nesting regions. They may migrate hundreds or even thousands of miles. In the water, their path is greatly affected by powerful currents. Despite their limited vision, and lack of landmarks in the open water, turtles are able to retrace their migratory paths. One explanation of this phenomenon is that sea turtles use the earth’s magnetic fields to navigate.

General Behavior

Sea turtles are generally solitary and usually interact with one another only for courting and mating. Sexual maturity varies with species, ranging early with the hawksbill at three years and age twenty to fifty for the leatherback. During mating season, two or more males may court a female and the male attaches himself to the back of the female’s shell and then folds his long tail under her shell to copulate. Fertilization is internal and copulation takes place on the surface or underwater, often close to shore. Females may mate with several males just prior to nesting season and store the sperm for several months. When she finally lays her eggs, they will have been fertilized by a variety of males. This behavior may help keep genetic diversity high in the population.

Nesting & Reproduction

Sea turtles usually nest in intervals of two to three years although some nest yearly. Depending on the species, females may nest from one to ten times during a nesting season. Only the females come ashore to the beach to lay their eggs a few weeks after mating.

When the female Leatherback is ready to nest, she will choose a beach without a coral reef, one close to the deep water, such as ’s Beach. Crawling up from the ocean, she will locate a dry area and begin the arduous task of nest excavation. Using her flippers and the rotation of her body, she will dig an egg cavity that is approximately 70 centimeters deep. She will then lay 80 to 100 eggs, a process that can take over two hours. Eggs are often referred to as the size of billiard balls: she lays an average of 80 fertilized eggs and 30 smaller, unfertilized eggs in each nest. After she is finished, she will carefully cover and camouflage the clutch, and may even construct false nests to fool predators. Her role now complete, she will depart to the ocean, leaving her eggs to their fate.

Remarkably, most female turtles share a nesting instinct that drives them to return to the beach of their birth, or natal beach, in order to lay eggs. In fact, her ability to successfully reproduce depends on the ecological health of this original habitat. However, recent satellite tracking data indicates that the Leatherback, unique among turtles in many ways, may return to a range area or region, rather than a natal beach. The Caribbean coastline of Costa Rica is an example of one of the most important Leatherback nesting regions in the world.

When the female turtle comes ashore at night to lay her eggs, she will first dig a body cavity with her front flippers, and then use her back flippers to dig out the nest. Depending upon the species, 80-120 eggs will be deposited in the cavity. Afterwards the female will laboriously cover the nest with sand and often even create another false nest to confuse predators, before she finally crawls back to the sea. Incubation varies with species, clutch size (number of eggs) and temperature, but averages from 45-70 days.

Hatchlings

Hatchlings use a caruncle, a temporary egg tooth to break open their shells. It may take several days for a group of hatchlings to dig their way up out of the nest cavity. Although they usually emerge at night, coolness of sand temperature and other factors influence their emergence. The hatchlings crawl towards the ocean in small groups. They must make it to the ocean quickly so they don’t die from dehydration or predators. When a hatchling reaches the surf, it swims continuously for 24-48 hours to get to deeper water away from predators. The turtles must survive several years in a relatively protected area away from predators and one with ample food supply. Juveniles will spend time eating and growing in habitats near the shore. Once they reach adulthood, they migrate to find a primary feeding ground. During mating season, the sea turtles will migrate closer to their nesting beach.

Why Sea Turtles Are Endangered

Unfortunately, there are many reasons why sea turtles are now at risk

  • Human harvesting of turtles and their eggs.
  • Destruction of nesting habitats.
  • Commercial fisheries who use longline fishing practices or gill nets and do not use Turtle Excluder Devices (TEDS).<l/i>
  • Pollution affecting nesting habitats and/or species: such as entanglement in marine debris; plastic debris, and commercial and industrial ocean water pollution from oil spills and chemical waste.
  • Global Warming.
Vital to the Eco-system

Sea turtles contribute to the delicate balance of ecosystems in our oceans and on the beaches where they nest. Their presence helps replenish both sea and beach nutrients and helps maintain the equilibrium of marine vegetation. For example, without Green turtles to feed on sea grass, the grasses would become overgrown and diseased which would have a negative impact on the many species that rely on this vegetation for sustenance. Sea turtles also play a significant role in balancing the oceans’ food chain. Leatherbacks for instance, consume large quantities of jellyfish, which feed on fish larvae. Some scientists are now looking at the possibility that the severe decline of Leatherback turtles over recent decades may have allowed for a proliferation of jellyfish, thus contributing to the drop in fish populations in the world’s oceans.

Sea turtles also support the health of our terrestrial ecosystem. The nutrients from their eggs bring food energy to species on beaches and sand dunes, which has an out-rippling effect to species in surrounding areas. The truth is that our planetary ecosystems are so intricately intertwined that it is difficult to predict just how far ranging the implications are when a global species such as the sea turtle, declines or is lost forever.

Scott Eckert’s (PhD) testimony to the Ocean Commission provides many examples of the interconnectedness of sea turtles and the eco-system:

Eckert also quotes another scientist, Dr. Nat Frazer, who eloquently describes their importance:

“Envision this with me . . . millions of sea turtles pulsing ashore onto the beaches . . . fertilizing the rims of thousands of islands and two continents. And after this wave of nutrients enters the rims, it is pulsed on up and into the interior lands in successive waves of biological transport. Year after year – tons of nutrients and billions of kilojoules of energy in a predictable, regular cycle – for tens of millions of years.

Envision this with me . . . millions of turtles grazing on seagrass beds, stimulating primary productivity at the base of the ocean’s food chain. And this surge of increased productivity works its way up the food chain, nourishing shrimp, mollusks, lobsters, and fish – as well as eventually pulsing onto the shore in the annual ballet of nesting activity.

Envision this with me . . . millions of sea turtles nibbling on sponges – trimming back the invading poriferans that otherwise would overgrow and shut down the coral reef machine. A constant system of checks and balances that also contributes to the gift of energy that sea turtles offer to the land each year in the form of nests and eggs. Year after year, for tens of million of years, the ecosystem engineers, these hawksbill and green and loggerhead and ridley and leatherback turtles, shape and improve and fine-tune the complex and mysterious and marvelous cybernetic machines of the oceans.”

We are a non-profit organization dedicated to sea turtle conservation, and we are proud to be a vital link to the international efforts of protecting marine life.

We appreciate gathering some of our data from the resources below. Many of these websites have additional pages with links that will provide more detailed information about sea turtles. In addition, we gratefully acknowledge the photographers who have given us permission to use their turtle photos.

Sea Turtle Resources

IUCN – The World Conservation Union: For information on Taxonomy and endangered species

Article by P.Tyson, Impact on Animals involving the Magnetic Field on animals

Amazing turtle information including satellite tracking

Endangered Species Act home page

Great page to see photos of all species
Important Political Action and other valuable information: Sea Turtle Restoration Project

  • Is the largest sea turtle in the world, averaging 4 to 6 feet (125-185 cm.) in length and 550 to 1550 pounds (250-700kg). Not only is the leatherback the largest turtle in the world, but it is also the largest reptile.
  • A male leatherback, found on the coast of Wales in 1988, was 9.5 feet long (about 3 meters) and weighed almost 2,000 pounds (908 kg).
  • Is the only sea turtle with a soft shell. It has a leathery, oil-saturated carapace that is dark gray to black with white or pale spots.
  • The widest ranging of sea turtles it inhabits nearly all the earth’s oceans and visits the shores of every continent except Antarctica.
  • Feeds primarily on jellyfish.
  • Nest at intervals of 2 to 3 years, though recent research has indicated they can nest every year.
  • Nests between 6 to 9 times per season, with an average of 10 days between nesting.
  • Does not necessarily return to a natal beach to nest, but does return to a range area.
  • Is in extreme danger of extinction. Primary causes for this are commercial fishing, egg harvesting, coastal development and environmental degradation.

Unlike Any Other Turtle

Unique among sea turtles, the Leatherback is perhaps, the most mysterious of its order. Mostly pelagic, the Leatherback spends so much of its life in the deep ocean that it is difficult for researchers to know its sea-going habits. They are the widest ranging of all sea turtles, migrating thousands of miles in open waters. Their streamlined bodies and powerful front flippers evolved for distance swimming.

This global aquatic traveler inhabits three of the earths four oceans, visiting the shores of five out of six continents. The Leatherback visits these shores only briefly, and for the singular purpose of nesting. Its unique ability to regulate its internal temperature enables it to inhabit much colder waters than other sea turtles. It is common for Leatherbacks to dive 3000 feet; they have also been observed diving to frigid depths of nearly 5000 feet.

The Leatherback is the only sea turtle with a soft carapace. This leathery hide, (ala the name) is extremely oily. In fact, the leatherback is oily right down to the very bones. The carapace has seven distinct ridges running lengthwise.

On average, the Leatherback turtles in the Caribbean grow larger than those found in other locations.

Magnetic Fields Influence Migration of Leatherbacks

There has been extensive research conducted regarding the sea turtles’ abilities to return to their nesting regions and sometimes exact locations from hundreds of miles away. In the water, their path is greatly affected by powerful currents. Despite their limited vision, and lack of landmarks in the open water, turtles are able to retrace their migratory paths. Some explanations of this phenomenon have found that sea turtles can detect the angle and intensity of the earth’s magnetic fields.

The Reproductive Cycle and Nesting

Courtship and mating occur during a brief window of time when the female is receptive. Females mate with several males before nesting and store the sperm in their bodies for several months. This behavior allows for the greatest genetic diversity within the species.

When the female Leatherback is ready to nest, she will choose a beach without a coral reef, one close to the deep water. Crawling up from the ocean, she will locate a dry area and begin the arduous task of nest excavation. Using her flippers and the rotation of her body, she will dig an egg cavity that is approximately 70 centimeters deep. She will then lay 80 to 100 eggs, a process that can take over two hours. Eggs are often referred to as the size of billiard balls: she lays an average of 80 fertilized eggs and 30 smaller, unfertilized eggs in each nest. After she is finished, she will carefully cover and camouflage the clutch, and may even construct false nests to fool predators. Her role now complete, she will depart to the ocean, leaving her eggs to their fate.

Hatchlings

Hatchlings emerge in 60 –65 days, depending on sand temperature, which also determines the sex of the hatchling. They crack their shells open by using their “caruncle”, a temporary, sharp egg tooth, which falls off after birth. Struggling up from the bottom of the nest to the sand’s surface, emergence entails an ordeal that can last a few days. Because hatching takes place beneath the sand, emergence from the shell is never observed under natural conditions. Not all eggs hatch and not all hatchlings make it to the surface. Those that do emerge successfully may not survive the trek from nest to the ocean. Predators, scorching midday heat, obstacles, both natural and manmade will thwart their journey. In fact, only one in a thousand hatchlings will make it through the perilous journey to adulthood.

Extinction

Leatherbacks are in immanent danger of extinction. A critical factor (among others) is the harvesting of eggs from nests. Valued as a food delicacy, Leatherback eggs are falsely touted to have aphrodisiacal properties in some cultures. The leatherback, unlike the Green Sea turtle, is not often killed for its meat; however, the increase in human populations coupled with the growing black market trade has escalated their egg depletion. Other critical factors causing the leatherbacks’ decline are pollution such as plastics (leatherbacks eat this debris thinking it is jellyfish; fishing practices such as longline fishing and gill nets, and development on habitat areas. Scientists have estimated that there are only about 35,000 Leatherback turtles in the world.

Leatherback’s Role in the Ecosystem

We are often unable to understand the critical impact a species has on the environment—that is, until that species becomes extinct. Even if we do not know the role a creature plays in the health of the environment, past lessons have taught us enough to know that every animal and plant is one important link in the integral chain of nature.

Some scientists now speculate that the Leatherback may play an important role in the recovery of diminishing fish populations. Since the Leatherback consumes its weight in jellyfish per day, it helps to keep Jellyfish populations in check. Jellyfish consume large quantities of fish larvae. The rapid decline in Leatherback populations over the last 50 years has been accompanied by a significant increase in jellyfish and a marked decrease in fish in our oceans.

Saving sea turtles is an International endeavor. Save The Turtles, Inc. is proud to be among the many respected organizations fighting for the survival of the Leatherbacks.
Resources:
We gratefully appreciate the following resources we have used in compiling some of our information:

  • Caribbean Conservation Corporation: http://www.cccturtle.org
    Everything you want to know about sea turtles: satellite tracking of turtles’ migration, scientific reports from leading biologists, newsletters.
  • Eckert, Scott PhD: “Testimony before the U.S. Commission on Ocean Policy”: May 2002
  • Sea Turtle Restoration Project: We urge you to check out this site, especially on the top left side, the activists’ corner. Robert Ovetz Ph.D and team have rallied the United Nations for safer fishing practices. There is a great deal we can do to save sea turtles! http://www.seaturtles.org
  • Great resource including a marine newsletter and photo library:: http://www.seaturtle.org/
  • Annual Symposium On Sea Turtle Biology and Conservation, Philadelphia, USA
    Troeng, Sebastian (CCC), D Chacon (ANAI), B. Dick (Pacuare)
  • Playa Grande in Costa Rica: http://www.leatherback.org

Photo © Caroline Rogers

  • Named for its narrow head and hawk-like beak.
  • One of the smaller sea turtles. Average adults are 205 to 3 feet in length (76-91 cm) and weighs between 100-150 pounds (40-60 kg).
  • Elliptical-shaped carapace, which can be orange, brown or yellow.
  • Most tropical of all sea turtles. Found in both tropical and subtropical waters in the Atlantic, Pacific and Indian Oceans.
  • Eats primarily sponges, squid, shrimp and anemones.
  • Nests at intervals of two, three or more years. Nests between two to four times each season.
  • Nests between 6 to 9 times per season, with an average of 10 days between nesting.
  • Listed as an Endangered Species due to the hunting of their prized shell.

Migration of the Hawksbill

Hawksbills are usually found around coastal reefs, rocky areas, estuaries and lagoons.

They have been located from the eastern Atlantic to the southern tip of Africa. In the Americas, Hawksbills occur in the east Pacific from the U.S. to Peru and in the West Atlantic from Nova Scotia to Brazil. Additionally, they are found in the coastal waters of Australia and Indonesia.

The Reproductive Cycle and Nesting

Female Hawksbills nest every two to five years. Each time, they lay from two to four clutches of eggs at two-week intervals before returning to their feeding grounds. After coming to shore and digging a nesting pit, the female lays an average of 160 eggs in each nest. Like most species, it is believed the female returns to her natal beach, the same place where she was born, to lay her eggs. There are an estimated 22,900 nesting females in the world.

Hatchlings

Hawksbill eggs hatch in about 60 days. After emerging from the eggs, the small hatchlings travel en-masse to the ocean, where they swim continuously for at least three days to reach the safety of deep water. After they grow to about 8-12 inches, the Hawksbills relocate to shallow waters, where they spend years foraging for food and maturing in size.

Endangered Status

The Hawksbill turtle is categorized as endangered under the U.S. Federal Endangered Species Act, meaning it is in danger of extinction within the foreseeable future. The International Union for Conservation of Nature and Natural resources has also listed it as critically endangered. The unusual shell of the Hawksbill turtle, often called the “tortoise shell” is commonly used to make jewelry, and hair ornaments. The harvesting of the Hawksbills shell for these decorative items is the greatest threat to the species even though there is an international ban on trafficking them.

Ecosystem Roles

Hawksbills feed mostly upon sponges in coral reef habitats. The delicate balance of our ecosystem is explained by Scott A. Eckert, PhD: “Sponges are major contributors to reef biomass and compete with other reef organisms for space. By keeping sponge populations in check, hawksbills help to preserve a balance between coral and sponge species in tropical reef ecosystems.”

Resources:
We gratefully appreciate the following resources we have used in compiling some of our information:

Photo © Marco Giuliano/Fondazione Cetacea

  • Pacific loggerheads migrate over 7,500 miles) between nesting beaches in Japan and feeding grounds off the coast of Mexico
  • Loggerheads were named for their relatively large heads,
  • Loggerheads are the most abundant species of sea turtle found in U.S. coastal waters.
  • Largest hard-shelled turtle in the world.
  • Life span is at least 30 years and up to 50 years or more.
  • Most loggerhead deaths occur due to drowning in shrimp nets, as well as due to longline fishing practices.
  • As many as 100 species of animals and plants have been recorded living on one single loggerhead turtle.
  • From hatchling to adult, a loggerhead increases its weight more than 6000 times!
  • A female loggerhead tracked at sea made up to 500 dives every 12 hours.

Description:

This species is the largest hard-shelled turtle in the world. The Loggerhead’s name was derived from its overly large head that is comprised of a horny beak, which is significantly thicker than in other sea turtles. They have powerful jaws and enable them to feed on hard-shelled prey, such as whelks and conch. The carapace is slightly heart-shaped and reddish-brown /rusty in color. Their front flippers contain two claws. The length of adults is approximately three to four feet, and they can weigh from 170– 500 pounds.

Habitat, Migration and Nesting

Loggerheads migrate great distances and are found in the Atlantic Ocean from Argentina to Nova Scotia. The highest populations in North America are found on barrier islands from North Carolina to the Florida Keys. Their primary habitat is in southeastern United States ranging southward to South America and extending eastward to Africa and the Mediterranean as well as areas of the western Pacific and Indian Oceans. Loggerheads are the most common turtle in the Mediterranean, nesting on beaches from Greece and Turkey to Israel and Libya. Like other sea turtles, it is believed the Loggerheads have an ability to use the Earth’s magnetic field to navigate across open oceans. Loggerheads nest on ocean beaches, generally preferring high energy, relatively narrow, steeply sloped, coarse-grained beaches
Females reach maturity around 35 years old and it is thought that they return to their natal beach, the same beach where they were born, to lay their eggs. Their clutch size is usually 100 or more eggs.

Vital to the Ecosystem

According to WWW, ‘Loggerhead turtles eat many types of invertebrates, in particular mollusks and crustaceans, and can change the seabed by “mining” the sediments for their favorite prey. Also, loggerhead turtles carry veritable animal and plant cities on their shell. As many as 100 species of animals and plants have been recorded living on a single Loggerhead turtle. These animals and plants depend on turtles to have somewhere to live and to prosper. The future for many of these species is intimately linked to marine turtle survival”.

Threats to the Survival of Loggerheads

Like all sea turtles, they are in danger in the oceans and also on beaches. Their nests are often lost to predators such as dogs, crabs, sea birds and ants as well as to shoreline erosion. Hatchlings are preyed upon by mammals, sea birds, crabs and carnivorous fish. Sharks and other large fish remain formidable predators to Loggerheads and all other sea turtle species throughout their entire life cycle. Loggerheads’ life span can range from 30 years to 50 years or more.

Loggerheads are listed as “Threatened” on the Endangered Species Act, as well as with the IUCN Red List. Most deaths occur due to drowning in shrimp nets or as a result of longline fishing practices. Like all turtle species, human predation and harvesting is a serious threat to their survival: Loggerhead eggs and meat are sold on the black market for consumption and their shells are used to make items such as boat paddles.

The total Loggerhead population is currently estimated at about 60,000.

Resources:

We gratefully appreciate the following resources we have used in compiling some of our information:

Photo © 2005 Robert Van Damm

  • Is the largest hard-shelled sea turtle.
  • Receives its name from the color of its body fat, which turns green as a result of an algae-based diet.
  • Adults average 3.5-4 feet in length. The largest green turtle ever found was 5 feet (152 cm) in length and 871 pounds (395 kg). Adults weigh between 300 – 400 pounds (136-180 kg).
  • Easily recognizable because of its distinct pair of prefrontal scales located in front of the eyes.
  • The carapace color varies from pale to very dark green and plain to very brilliant yellow, with brown and green tones and radiating stripes.
  • Found in all of the world’s temperate and tropical waters.
  • Eating primarily seagrass and algae, it is only turtle that is strictly herbivorous as an adult.
  • Nests at intervals of two, three, or more years.
  • Migrates long distances to return to natal beach.
  • Is in danger of extinction primarily due to commercial fishing and human harvesting of turtles and their eggs.

Migration of Green Turtles

Unlike other species, Green Turtles are found in all temperate and tropical waters throughout the world. Green turtles spend most of their lives in the ocean near the coastline and around islands. They often live in bays and protected shores, especially in areas with seagrass beds. Nesting green turtles are thought to return to the same beach where they were born. In order to return to their natal beaches, Green turtles migrate long distances from their feeding areas.

The Reproductive Cycle and Nesting

Nesting occurs in intervals of two, three or more years, but wide year-to-year fluctuations are reported. Generally, the females nest 3-5 times each season. Green turtles only nest during the night, when the female climbs out of the ocean to an area in the upper beach. After digging a pit with her rear flippers to carve out a bottle-shaped burrow, she lays her eggs. On average, the female lays 115 leathery-skinned eggs. After burying the eggs with sand, the female turtle returns to the ocean. The eggs incubate for around 60 days before the hatchlings emerge. It is estimated that there are about 88,520 nesting females in the world.

Hatchlings

Like other hatchlings, Green turtles hatch with the aid of an egg tooth, or a temporary protrusion attached to the beak that allows the hatchling to crack through the shell. Weighing about one ounce each, the hatchlings emerge from the nest as a group in a process that lasts several days. Hatchlings follow the brightest horizon to the ocean, where they stay for at least a year before returning to land.

Endangered Status

The Green Turtle is listed as Endangered under the U.S. Federal Endangered Species Act, meaning that it is in danger of extinction within the foreseeable future. The International Union for Conservation of Nature and Natural Resources also listed the Green Turtle as endangered, predicting that it will face a very high risk of extinction in the foreseeable future. There are many factors contributing their endangered status. Although illegal in most countries, Green turtles are hunted relentlessly on the beach as well as on the ocean. and are often sold openly in many towns. The fishing and shrimp industries contribute to the decline in their population by not using Turtle Excluder Devices (TEDS), and still using detrimental practices such as longline fishing or gill nets. In addition, coastal developments and environmental degradation play a large factor in the Green turtles’ fate.

Green Turtles and the Ecosystem

Green turtles consume large quantities of seagrass. Studies in Caribbean waters indicate that seagrass may support as much as 10,000,000 kg of Green turtles per square kilometer. Grazing by green turtles has significant effects on the structure and nutrient cycling in these systems (Eckert).

Areas cropped by Green turtles readily grow fresh grasses. The higher nutritional quality of this new vegetation subsequently, draws and sustains a wide variety of oceanic life. Scientists are concerned that declining populations of Green turtles will create ecological imbalances that could have long-term effects on the health of our oceans (Aragones).

Just how devastating would the loss of the Green turtle be to our planet’s seas? Scientists can speculate, but no one can really know the full impact until it is too late. It is reasonable to say; however, that the loss of such an ancient and globally prevalent creature would create a substantial alteration of the oceanic environment.

Resources:

We gratefully appreciate the following resources we have used in compiling some of our information:

  • Aragones, Lemnuel V, “A Review of the Role of the Green Turtle in Tropical Seagrass Ecosystems.”
  • Caribbean Conservation Corporation: http://cccturtle.org
  • Earthtrust http://earthtrust.org
  • Eckert, Scott PhD: Safeguarding Pacific Sea Turtles in the Oceanic Commons Commons

© Cynthia Rubio & NPS

Critically Endangered

Kemp’s Ridley turtles are one of the most seriously endangered of all sea turtles today. In 1947, a single Kemp’s Ridley arribada was calculated as having 42,000 nests. Today, the total population of females is estimated to be around 2,500. They are listed as Critically Endangered (facing an extremely high risk of extinction in the wild in the immediate future) by the International Union for Conservation of Nature and Natural Resources.

Nesting

Like its sister species the Olive Ridley, the Kemp’s Ridley utilizes the arribada (mass-nesting) as a nesting strategy. They nest more frequently than other species, every 1 ½ years and 2 to 3 times a season. They deposit around 110 eggs in their nest, which hatch in about 55 days. According to NOAA, “Kemp’s ridleys are the only sea turtle species that nests predominantly during daylight hours.”

Description

The Kemp’s Ridley is the smallest of sea turtles. Adults grow to be about 2 feet long and can weigh about 100 pounds maximum. The carapace is oval and gray-green in color. The under part of the shell or plastron is yellowish-white. There are 5 costal scutes on the carapace and 4 inframarginal scutes, which join the carapace to the plastron. The head is medium sized and triangular in form. Hatchlings are black. Unlike other sea turtles whose name reflects their appearance, the Kemp’s Ridley is named after Richard M. Kemp, a fisherman in the Keys of Florida, who first submitted this species for classification.

Habitat, Range and Migration

Unlike most other turtles, the Kemp Ridley spends most if its time in shallow seas and rarely swims in waters more than 160 feet. According to NOAA, “Adult Kemp’s primarily occupy neritic habitats. Neritic zones typically contain muddy or sandy bottoms where prey can be found. Their diet consists mainly of swimming crabs, but may also include fish, jellyfish, and an array of mollusks.”

The range of the Kemp’s Ridley is narrow compared to other sea turtles. Adults primarily inhabit the coastal waters off of Mexico. Their most important nesting ground is a 12-½ stretch of beach in the Mexican state of Tamaulipas. A few nest on Padre Island, off the coast of Texas and elsewhere along the Mexican gulf coast.

Hatchlings become caught up in the currents and eddies of the Gulf waters, and are re-distributed all along the Gulf and Atlantic as far north as Nova Scotia. Immature turtles can be found along the Atlantic coast as far north as Massachusetts and Canada.

Diet

Adult Kemp’s Ridleys are carnivorous bottom-feeders, eating a variety of animal foods from shallow waters. While they eat mollusks, fish, jellyfish, echinoderms etc, they have a marked preference for crabs and frequent the waters occupied by this favored delicacy.

Threats

The fact that the Kemp’s Ridley spends its sea going life in shallow coastal waters where much human sea harvesting takes place has likely contributed to its rapid historical decline. Shrimp trawls troll these shallow waters and many Kemp’s Ridley’s become the victims of incidental capture in their nets. Near shore fishing also exacts a toll.

Harvesting of eggs and slaughtering of nesting females during arribadas has also also played a significant role in bringing this animal to its current critically endangered status.
As with other sea turtles, habitat development and degradation hastens the decline of the species.

The enforced use of turtle exclusion devices by trawlers as well as the protection of nesting habitat during arribadas is required if this species is to recover from the edge of extinction.

Resources:

We gratefully appreciate the following resources we have used in compiling some of our information:

Cynthia Rubio & NPS, http://www.cccturtle.org/sea-turtle-information.php?page=species_world

IUCN 2007, 2007 IUCN Red List of Threatened Species. http://www.iucnredlist.org/. Downloaded on 16 December 2007

US Fish and Wildlife http://www.fws.gov

World Wildlife Fund https://www.worldwildlife.org

NOAA Fisheries http://www.nmfs.noaa.gov

WWF http://wwf.panda.org

© Kedar Gore

  • Named for it’s green/gray carapace
  • The most abundant sea turtle in the world.
  • Omnivorous, feeds on a wide variety of foods.
  • Nests in a mass-nesting event called an arribada. Nests two times a season.
  • Pelagic yet also inhabits coastal areas and estuaries.
  • Small by sea turtle standards, measuring only 2 to 2 ½ feet and weighing between 75 and 100 pounds.
  • Widely distributed across the globe in the tropical and sub-tropical oceans of the world.
  • Main threats to survival are egg gathering and killing of nesting females, shrimp trawling and other fishing practices.
  • Listed as endangered. The overall population has been reduced drastically in the last 60 years.

Nesting: The Grand Arrival

The most remarkable characteristic of the Olive Ridley is their nesting strategy. Hundreds to thousands of females converge in coastal waters then come ashore simultaneously in a spectacular mass-nesting event known as an arribada (Spanish meaning “arrival by sea”). Lepidochelys, which includes the Kemp’s Ridley, is the only genus of sea turtles to lay their eggs in arribadas.

How does the female know that the time is right for the arribada? Scientists have conducted research in order to find the answer to this question and have offered several theories. One theory suggests that females may release a hormonal scent or pheromone that queues the beginning of the event. There is also evidence that these mass-nesting events coincide with certain phases of the lunar cycle. So far, there is no definitive answer and the arribada continues to remain one of nature’s great mysteries.

The Olive Ridley nests two times a season and deposits an average of 105 eggs per nest.

Major Arribada Beaches in Costa Rica

Playa Ostional and Playa Nancinte in Costa Rica are two of the world’s major arribada sites. The annual nesting population at these two beaches has been calculated to be from 600,000 to 750,000. The largest arribada at Ostional was documented in 1995. In that one arribada (lasting about 10 days) approximately 500,000 sea turtles emerged from the sea to lay their eggs (Quirós, du Toit, Phd., 2000).

Not all females participate in the arribada. At Ostional and Nancinte beaches, in Costa Rica. it has been calculated that as many as 5000 of the total population of Olive Ridleys may nest individually. Females have been observed utilizing both individual and mass-nesting strategies.

Hatchlings emerge after incubating in the nest from 50 to 60 days. New hatchlings are only 1 ½ inches in size and weigh less than an ounce. Their coloration is primarily a dull black or charcoal with a greenish cast along the sides. They face the same odds as all other newly hatched sea turtles and many will never make it to sea, let alone adulthood. If they do make it to the water, they will continue to face threats from predation in lessening degrees as they grow larger. Once fully grown, their primary threats at sea are large sea predators and of course, humans.

Description

The Olive Ridley derives its name from its green/gray shell. They are small among sea turtle species, weighing between 75 and 100 lbs and measuring in at 2 to 2 ½ feet along the length of carapace. Variations in size occur region to region and the largest Olive Ridleys are found on the pacific coast of Mexico. They can be differentiated from the Kemp’s Ridley by their small heads and a greater number of scutes. Their scutes are large and smooth and the have least 6 laterals on each side and as many as nine costals.

Habitat and Migration

Although Olive Ridleys spend time in the open ocean, they also forage in coastal waters and estuaries. They inhabit three oceans, the Atlantic, Pacific and Indian and nest on many continents around the globe. The highest density of nesting sites is found on the pacific side of Mexico.

Annually, the Olive Ridley migrates from pelagic foraging areas to coastal waters (for breeding, nesting and shallow water foraging) and back again to the open ocean.

Diet

Olive Ridleys are omnivorous, meaning that they consume a varied diet from both plant and animal sources. Their jaws are powerful enough to enable them to consume mollusks such as sea snails and clams. They also eat crustaceans (crabs, lobsters and shrimp) as well as fish, jelly fish, tunicates and various algae.

To be an omnivore is to assume one of natures more successful dietary strategies. This adaptation means a species is less dependent on the availability any single food source and therefore, more able to adapt to extinctions or depletions of dietary resources. This may be contributing factor to the fact that the Olive Ridley is the most abundant sea turtle species on the planet.

Threats to Survival

Despite the relative abundance of the Olive Ridley today, their numbers have diminished by an astounding fifty percent during the last several decades. In the United States, they are labeled threatened or likely to come under danger of extinction in the foreseeable future. The International World Conservation Union (IUNC) has listed the species as endangered.

A primary threat to the Olive Ridley comes from human predation in the nesting habitat. The arribada with its large congregation of nesting females makes it possible for humans to collect huge quantities of eggs and kill or collect (to sell at market) hundreds or even thousands of turtles in one night. This practice of mass harvesting and killing over the past sixty years has caused local populations to plummet in many areas of the globe. Another form of human intrusion that threatens sea turtles is the permanent destruction of the nesting habitat through coastal degradation and development.

Thousands of Olive Ridley are killed annually at sea, becoming collateral damage to the practices of shrimp trawling and commercial fishing. It is estimated that 60, 000 sea turtles—mostly Olive Ridley —die every year as incidental bycatch in shrimp trawls along the coast of Central America (Arauz 1996). These losses could be avoided if regulations requiring turtle excluder devices (TEDs) were enforced. Other fishing practices such as the use of longlines and gill nets also contribute to the decimation of the Olive Ridley and other sea turtles in the open ocean.

Resources:

We gratefully appreciate the following resources we have used in compiling some of our information:

Arauz, R.M. 1996. A description of the Central American shrimp fisheries with estimates of incidental capture and mortality of sea turtles. Pages 5-9 in Keinath, J.A., D.E. Barnard, J.A. Musick, and B.A. Bell (compilers). NAOO Fisheries http://www.nmfs.noaa.gov/pr/species/turtles/oliveridley.htm

Caribbean Conservation Corporation: http://cccturtle.org

Costa Rica, the Land of Pure Life from the PBS series The Living Edens http://www.pbs.org/edens/costarica/ridley.html

Gore, Kedar: photographer of Olive Ridleys’ photos from http://seaturtle.org image library.

Mr. Bhau Katdare: photographer of Olive Ridleys’ photos from http://seaturtle.org image library.

Ostinal National Wildlife Refuge, http://www.costarica-nationalparks.com/ostionalwildliferefuge.html

NOAA FISHERIES, Office Of Protected Resources http://www.nmfs.noaa.gov/pr/species/turtles/oliveridley.htm

NOAA Fisheries, Pacific Islands Regional Office, http://www.fpir.noaa.gov/PRD/prd_olive_ridley.html

Red List Standards & Petitions Subcommittee 1996., Lepidochelys olivacea. In: IUCN 2007. 2007 IUCN Red List of Threatened Species. http://www.iucnredlist.org

Quirós, Anny Chaves & Leslie A. du Toit, Ph.D, Douglas Robinson, Marine Turtle Research Center (documentary video, Costa Rica, Land of Pure Life) http://www.pbs.org/edens/costarica/ridley.html

© Jarrad Sherborne

  • Named because its shell is very flat; other sea turtles have an arch to their shell.
  • Population estimate is only around 10,000 – 20,000 nesting females.
  • Smallest migratory range of any sea turtle: Breeds and nests only around Australia, but migrates to other areas.
  • Protected on CITES (Convention on International Trade in Endangered Species…)
  • Lays fewer eggs during a nesting event than any sea turtle species.

Description

Flatback Sea Turtles are unique in their appearance because their shell is flat, rather than having an arch. They can weigh around 200 pounds and are over three feet in length as an adult. Their coloring is olive-gray and they have only one claw on their flipper.

Range and Nesting

Flatbacks are found in the tropical areas around Australia and prefer shore waters, bays and coastal coral reefs. They are found around the Indonesian Archipelago and Papua New Guinea in the Pacific; however, it is reported that they only nest and breed in Australia. They lay around 50 eggs, the fewest of any species.

Threats To Their Survival

Flatbacks are listed as Vulnerable under the Australian Commonwealth Endangered Species Act.
Like other species, flatbacks survival is threatened because of human harvesting of their meat and eggs and drowning in shrimp and gill nets. They are also vulnerable because ocean pollution, and coastal development. In an article in International Herald Tribune, dated March 2007, Wayne Arnold writes, “But now environmentalists say that Barrow’s flatbacks may be among the victims of a plan by the oil giant Chevron to use Barrow Island for a roughly $8.6 billion project meant to supply natural gas to Japan and other energy-hungry nations.”

Resources:

We gratefully appreciate the following resources we have used in compiling some of our information:

Caribbean Conservation Corporation: http://cccturtle.org

Jarrad Sherborne, photographer/conservationist who works at the Barrow Island Turtle Reserve gave permission to use the Flatback turtle photo fromhttp://www.seaturtle.org/ image library.

International Herald Tribune

Sea Turtle Restoration Project: http://www.seaturtles.org/

US Fish and Wildlife http://www.fws.gov/home/feature/2007/seaturtles2.pdf