Posted on 27 March 2006.
Their Struggle to Survive
|A Hawkbill Turtle in its natural habitat
Editor’s Note: If you are looking for examples of how concerned people have mobilized to help a species, the worldwide efforts to save the Great Sea Turtles is a good place to start. If it weren’t for individuals getting involved on every continent, these ancient species, with lifespans that exceed humans, who travel thousands of miles through open ocean, might well be completely extinct by now.
The list of organizations helping to protect the seven species of Great Sea Turtles is partially represented at the end of this story, but there are far more than we could compile. A good place to find the names of hundreds of individuals and organizations helping the Great Sea Turtles is to access the directory at www.SeaTurtle.org.
In this personal account by EcoWorld correspondant Daniela Muhawi, the struggle of the Hawksbill Sea Turtle to nest on Kamehame beach in Hawaii is described in some detail. Probably the biggest threat to the Great Sea Turtles is the encroachment of civilization on their nesting beaches. Very few Sea Turtle hatchlings ever made it from these nests to the ocean, but nowadays with introduced predators including domestic cats, artificial lighting that make females think it’s daytime and keep them from coming ashore to lay their eggs, roads that block females from their nests, and of course poachers who remove and sell the eggs, the chances for the Sea Turtles to reproduce is slim indeed.
With the help of volunteers around the world who monitor beaches where Sea Turtles establish their nests, however, the odds swing back somewhat in favor of the species. These efforts, along with the steady adoption by fishermen of nets that provide an escape for large sea animals, have given the Great Sea Turtles hope, though they remain endangered. – Ed Ring
|A mama turtle’s flipper prints leave distinctive tracks
Are the Great Sea Turtles on the path to recovery?
“It’s amazing how well you can see with the full moon,”
whispers Heidi Minga, a Marine Biology Graduate and volunteer with the Hawaii Volcanoes National Park Hawksbill Turtle Project on Hawaii. “It looks kind of creepy though, as if anything could come jumping out of the water.”
The full moon casts an eerie light on the water and the black sand beach. All four volunteers watch the frothing waves, hopeful that the ever-evasive hawksbill turtle will emerge on the shore. The conversation died down a few hours ago and everyone is starting to doze off. Running on four hours of sleep for the past three nights have taken their toll. The volunteers are equipped with dimmed flashlights but they are only used on hourly beach checks. Any other lights might confuse or scare the female hawksbill turtles that are known to nest here.
Watching the soothing waves in the dark does not make the task of staying awake any easier. “Oh my GOD,” yells volunteer Megan Barker, “Something is crawling up my leg, what is it? Get it off me!!” Heidi turns towards her and shines a flashlight on her leg. “Ugh, hold still,” she says, “it’s another one of those centipedes.” The giant nine inch long centipede is making its way up to her thigh. Heidi flicks it off with the flashlight and stomps on its head. Stepping on the giant arthropod only pushes its hard body into the sand. It swiftly scuttles away into some nearby bushes unharmed. The excitement provides the team with some newfound energy that lasts till 2 a.m. Then the volunteers decide it is time to return to the cots laid out at the other end of the beach.
As if on cue, a hawksbill slowly pushes her 200 hundred pound body up the slope past the high tide line as soon as the last volunteer has left the beach. She makes a depression with her hind flippers under the morning glories that line the upper side of the beach and begins to lay her eggs. Her hind flippers curl up slightly with the effort of pushing the soft spheres out of her body and she is oblivious to her surroundings. As soon as she is finished laying her eggs, she gently pushes sand into the depression with her surprisingly dexterous flippers. After flattening the mound she crawls down the beach and disappears when a huge wave sucks her back into the water. Only a few hours later, Heidi wakes up at 6 a.m. to check the beach. She lets out a groan after sleepily stumbling upon the tracks left by the reptile that has eluded them for almost a week. “We should have stayed up longer,” Heidi says to herself.
|Even with some assistance making their first
trek from nest to ocean, very few of these tiny
hatchlings will live to adulthood
Hawaii Volcanoes National Park Hawksbill Turtle Recovery Project was created to ensure the turtles’ survival. Wildlife Research Supervisor, Will Seitz explains that “the project was started in the late 80′s because fishermen were reporting eggs dug up and eaten by mongooses at Kamehame and dead hatchlings were found on the rocks at Apua Point [Both beaches popular with turtles].”
Volunteers arrive in Hawaii from all over the world. Kevin Craine, an Elementary School Science Teacher, arrived in Hawaii hopeful to make a difference. “I wanted to use my summer vacation to help sustain the biodiversity of a fragile ecosystem. It was a great cause and I wanted to do something different.”
With all the threats Hawksbills and many other marine turtles have to face, their future seems bleak. Kevin explains: “One of the more appalling reasons that many turtles are facing extinction is due to poaching. Turtles are still killed for their shell, their meat, and their eggs around the world. Many are also inadvertently killed while crossing a road to nest. Hotel development has destroyed many nesting habitats as well.”
All seven species of marine turtles are listed on Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), and six of the seven species of marine turtles are listed as Endangered or Critically Endangered.
The National Oceanic and Atmospheric Administration (NOAA) on their NOAA Fisheries website provide a list of the endangered species of sea turtles:
Green turtle, Chelonia mydas, Endangered/Threatened
Hawksbill turtle, Eretmochelys imbricata, Endangered
Kemp’s ridley turtle, Lepidochelys kempii, Endangered
Leatherback turtle, Dermochelys coriacea, Endangered
Loggerhead turtle, Caretta caretta, Threatened
Olive ridley turtle, Lepidochelys olivacea, Endangered/Threatened
The flatback turtle, found only in the tropical waters of Northern Australia, is listed as vulnerable.
The Australian Government’s Department of the Environment and Heritage gives an excellent description of Marine Turtles:
|A Green Turtle swimming in the
tidewaters of Kamehame beach, Hawaii
“Marine turtles have lived in the oceans for over 100 million years. They are an integral part of the traditional culture of many coastal indigenous peoples throughout the world. Marine turtles migrate long distances between their feeding grounds and nesting sites. They have a large shell called a carapace, four strong, paddle-like flippers and like all reptiles, lungs for breathing air. The characteristic beak-like mouth is used to shear or crush food. All marine turtle species are experiencing serious threats to their survival. The main threats are pollution and changes to important turtle habitats, especially coral reefs, seagrass beds, mangrove forests and nesting beaches. Other threats include accidental drowning in fishing gear [when turtles are dragged in the nets for hours], over-harvesting of turtles and eggs, and predation of eggs and hatchlings by foxes, feral pigs, dogs and goannas. [Other predators such as cats and mongoose prey on nests and hatchlings in other regions of the world.]”
Fortunately, new fishing techniques that allow turtles to escape nets unharmed are currently implemented by many shrimp trawlers. These Turtle Excluder Devices (TEDs) are a grid of bars that allow shrimp to filter through and divert larger animals like turtles and sharks to a hole out of the net. This drastically reduces the number of turtles killed as bycatch.
Many local families that once enjoyed having turtle on the menu are aware of the declining numbers and will no longer harm the animal. However, this does not mean that turtles are safe from humans. In many parts of the world, turtles are still poached illegally by those wanting to make a profit. Enforcement is lax and turtle eggs, meat, and jewelry can be found for sale in local markets. Poaching will continue as long as turtle items are bought.
Little is known about the life cycle of the marine turtle while at sea, especially when the turtles first enter the water as hatchlings. These years are also known as “the lost years” coined by Archie Carr. Adults feed in the ocean until reaching sexual maturity at thirty to fifty years; then they may migrate up to 3000 kilometers, back to their nesting sites.
|Increasing use of the “turtle exclusion device”
has drastically reduced the number of turtles
inadvertantly trapped and killed by shrimp trawlers
(Source: Australian Fisheries Management Authority)
Australia’s Department of the Environment and Heritage explains the biology of Marine Turtles: “After reaching sexual maturity, marine turtles breed for several decades, although there may be intervals between breeding of two to seven years. When breeding, nesting females return to the same area, thought to be in the region of their birth. As hatchlings, they become imprinted to the earth’s magnetic field and, possibly, the smell of the waters adjacent to the nesting beach which allow them to successfully complete their migration.”
Courtship and mating take place in shallow waters near the nesting beach. Females often mate with more than one male. After mating, the males return to the feeding grounds.
Between nesting efforts, female turtles gather adjacent to the nesting beaches. They return to the same beach to lay consecutive clutches. A female green turtle usually lays six clutches of eggs at two weekly intervals. When ready to lay eggs, the female turtle crawls out of the sea to above the high water mark, usually about one hour before to about two hours after the night high tide. In preparation for nesting, the female turtle scrapes away loose sand with all four flippers to form a body pit. She then excavates a vertical pear-shaped egg chamber with the hind flippers. Often, the sand is unsuitable for nesting, especially if it is too dry, and the turtle moves on to another site. Incubation time and sex of the hatchlings depend on the temperature of the sand. Warm, dark sand produces mostly females and the eggs hatch in seven to eight weeks. Eggs laid in cool, white sand mostly result in males and the eggs take longer to hatch.
The survival rate of sea turtles is naturally small: A tiny fraction of sea turtles survive into adulthood once they enter the ocean. “I saw seven nests hatch while on the Big Island in Hawaii,” says Kevin with a smile, “with an average of about 120 hatchlings per nest, I saw about 840 tiny hawksbill hatchlings scurry into the water as fast as they could. As volunteers we were also responsible for ensuring that the turtles reached the ocean. We would have to help them in the water if there were coastal rocks hindering them from reaching the water or if predators such as crabs and mongoose where nearby. [It is important however, that the hatchlings remember the nesting beach. Babies are only helped as a last resort and are forced to crawl towards the water from the nest as they would do naturally].”
Not only does it take decades for a turtle to reach maturity and lay her eggs, but barely a fraction of the hatchlings will survive to contribute to the next generation. Hatchlings face a number of threats: Crabs, birds, rats, and other predators pick of the hatchlings as they frantically make their way to the water. The turtles that make it to that far have to find refuge from eels and the thousands of aggressive fish that would love to snack on a baby turtle. Adults must reproduce over the course of many years to ensure the population’s survival. Unfortunately, mortality rates are high, even in adults, with current trends in pollution, fishing nets and disease.
|Barely visible, a hatchling emerges from the
sand to find the sea. A small fraction of these
babies will return, three decades later, to the
same beach to lay eggs of their own.
Heidi Minga has a feeling that at least one of the hatchlings she helped to the water survived: “I saw hundreds of baby turtles that wouldn’t have made it without our help. Maybe one of them will survive and that’s all that matters. But I have a good feeling about one specific hatchling. After a nest’s main emergence [when most of the hatchlings dig their way out of the sand in one large group], we are supposed to monitor the nest for any stragglers for the following two nights. Well, nothing happened the first night after a main emergence at Apua beach. The second night, we were exhausted and I had fallen asleep at 2 a.m. At 4 a.m. I felt the sudden urge to get up and check the nest. When I got there, I saw a little head poking out of the sand. The sun was coming up and he would have fried up from the heat if I hadn’t helped him. Turns out he was tangled in some roots. I helped him out and then ran him to the ocean. He’s a fighter and I have a good feeling about that little guy.”
Females return to the shoreline where they first crawled into the water as hatchlings. Unfortunately, in the thirty years it takes for a turtle to mature, the sandy beach they experienced as hatchlings might have undergone dramatic changes. Hotels, lounging beach goers, off-road vehicles, and other changes to the coast make it unsuitable for nesting. Rather than find another beach, females are known to release their eggs in the ocean where they are immediately rendered unviable.
During the nesting season, volunteers patiently wait on a variety of pristine and secluded beaches hopeful that a hawksbill turtle will painstakingly crawl up the sand and lay her eggs. Ideally, the volunteers will be there to take notes, check the turtles’ tags, or tag a new turtle. Some volunteers leave the program after 3 months without seeing a single Hawksbill.
Kevin was one of the lucky few who saw his fair share of nesting females. “I saw six females nest while in the program for four months,” he explains, “we would sit out on the beach from dusk till two in the morning. We would sit there, either on the sand or on chairs provided to us by the program, and watch the surf for signs of a hawksbill mama emerging. At one of the beaches we work at, Kamehame, most of the turtles that climb up are green sea turtles and they are just there to rest. It is one of the most popular beaches and at dusk dozens of green turtles are visible when they come up for air. We were there for the hawksbills, though. We had to be patient and alert. If it happened to be dark without the benefits of the full moon, we would have to rely upon our hearing and sense of smell. The smell of a turtle that has spent her entire life in the ocean is very distinctive.” The hawksbill turtle only comes on shore to nest. This occurs during the summer months. The males generally stay in the ocean and never leave the safety of the water.
|Saving turtle hatchlings includes the
unpleasant task of capturing and destroying
non-native predators such as this Mongoose.
Volunteering for the Hawksbill Project entails some other duties that are in no way glamorous. Non-native mongoose, rats and feral cats are numerous in Hawaii and make an easy meal of baby turtles and turtle eggs. Volunteers trap these animals and euthanize them humanely. “I had to euthanize one kitten and two mongoose on my first day out in the field,” Heidi complains, “it was really hard for me but I knew it helped the ecosystem. These introduced species not only predate on turtles but other native species in Hawaii. We would see paw prints and dug up nests along the beach. I noticed that trapping made a big difference, though. We strategically set up traps at nesting sites. At first there was a mongoose or rat in every trap. Within a few weeks the traps would always wind up empty and tracks would not show up around the nests at all.”
Conservation work is a collaborative effort. Through the help of such organizations as the Hawksbill Turtle Recovery Program, U.S. Fish and Wildlife Service, National Marine Fisheries Service, WWF (Word Wildlife Fund), the Marine Conservation Society, their volunteers and countless other international groups, marine turtles may eventually make it off the endangered species list. Will Seitz urges those who are interested to apply to the program: “Funding is a challenge,” he says, “We are on soft money year to year. Our program is successful thanks to the dedication of volunteers. If anyone is interested in volunteering with the Hawksbill Project, email HAVO_Turtle_Project@nps.gov or call (808)985-6090 for more information and an application.”
Many organizations rely on volunteers for success. The lucky few who bear witness to the first part of the turtle’s lifecycle leave the program knowing that they have just seen one of nature’s many miracles: seeing a vulnerable egg develop into a hatchling that will start the process all over again in no less than three decades.
“Based on the odds,” Kevin says, “all hatchlings I saved might perish in the ocean before getting a chance to reproduce. On average, only one out of five-thousand babies will survive the 20-30 years to become a reproductive adult. In the end, you don’t really know if your work makes a difference&that’s the hardest part of doing conservation work. You might increase the babies’ chances of making it to the water, but in the end you don’t really know if you’ll actually make an impact. There’s no way of knowing unless you try.”
Since 1991, The Hawksbill Turtle Recovery Project has tagged 67 adult female hawksbills, documented and protected over 580 nests, and assisted over 63,000 hatchlings to the ocean on the island of Hawaii.
TURTLE RECOVERY PROGRAMS (PARTIAL LIST)
Hawksbill Sea Turtle Recovery Project
Caribbean Conservation Corporation and Sea Turtle Survival League
Anegada Sea Turtle Recovery Project
British Virgin Islands
Hawaii Wildlife Fund
Dept. of Aquatic & Wildlife Resources – Turtle Program
Barbados Sea Turtle Project
National Fish & Wildlife Foundation – Sea Turtle Conservation Projects
Dozens of projects throughout the Americas
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