Sea Turtles Tagged with Satellite Transmitters
-- View Tracking Maps on the Internet --
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| A loggerhead turtle makes her way back to the Atlantic after laying eggs at the Archie Carr National Wildlife Refuge, near Melbourne, Fl., Aug. 20, 1999. The turtles lay their eggs at night. The sandy covering on her back comes from her efforts to hide her nest. |
It was 3:00 a.m. on a hot and muggy August night in Florida. The only sounds were the thunder in the distance, waves crashing on the shore, and a strange bumping noise. The latter came from a miraculous remnant of the dinosaur age -- a 300-pound loggerhead sea turtle, a threatened species, bumping her head against a temporary restraining box dropped over her by researchers.
She had just laid her eggs. She was impatient. And she had three more hours to go in the box.
Her adventure began sometime after midnight, when, heavy with about a hundred eggs deep in her shelled body, she swam with the waves on the beach at Archie Carr National Wildlife Refuge near Melbourne, Florida. She pulled herself out of the frothy seas and up the still-warm sands to the edge of the dune vegetation. Propelling her huge form -- better suited to seas and surf than dry sand -- she left the tell-tale trail of alternating comma marks in the sand that would allow researchers to discover her presence on the beach. Then she began to dig her egg chamber with her powerful, foot-and-a-half-long rear flippers.
She excavated a hole about three feet deep in the moonlit white sands, then pivoted and began to jettison her precious cargo of golf-ball-sized eggs -- a new generation of the same creatures that once swam with the ancient, deep-sea dinosaurs. Her crucial, life-sustaining job almost finished, she covered her nest cavity with sand, burying the eggs to keep them safe from predators. The hot sun and warm sand would incubate the "clutch" of eggs until, 50 or 60 days later, throngs of hatchlings would break free from their egg casings and dig to the top of the sand and scamper into the sea. But that was still two months away.
Right now, she had to camouflage her nest to guard her secret. Using her front flippers this time, she swept sand to hide her treasure. She only had a few more minutes on land, then back to the ocean until her next trip up the beach, one of the four to six egg-laying trips she makes in a nesting season. Then she would return to this area in two to three years to begin again this ritual to perpetuate her species.
Then the box slipped around her. It was only two feet high, four feet across and five feet long open on the top and bottom, and carpeted along the inside walls to prevent injury, but it was enough to halt her progress toward her home -- the sea. The box served to hold her in place for an important study.
While we know where many sea turtles come to lay their eggs, we don't know much about where they live when they're not nesting and what routes they take to get there and how long it takes them -- crucial knowledge that could lead to key conservation strategies. To address these questions, a group of federal, state, non-profit and educational entities agreed to gather the information on loggerhead sea turtles.
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| (l-r) Barbara Schroeder, NMFS, Dr. Llew Ehrhart, UCF & Sandy MacPherson, USFWS, put the finishing touches on the fiberglass layers attaching a satellite transmitter on a loggerhead turtle on the Atlantic coast near Melbourne, Fl. Aug. 20, 1999 Photo by Tom MacKenzie, USFWS. |
"Understanding where loggerheads nesting in the United States go after they leave the nesting beach, what routes they take to get there, and where the principle feeding areas are located will help us learn what threats they face there and what we need to do to protect them," said Sandy MacPherson, national sea turtle coordinator for the U.S. Fish and Wildlife Service and a member of the research tagging team. "This information is critical to determine where international cooperation is needed to ensure recovery of sea turtles."
Biologists from the Fish and Wildlife Service, National Marine Fisheries and University of Central Florida carefully monitored and comforted the loggerhead as they removed the barnacles from her aged back and cleaned the surface of her shell to help keep the transmitter attached. They attach the transmitter, about the size of VHS tape, to the top of her shell, then layered resin-coated fiberglass strips over it to secure it in place. Each layer had to dry, so the process took about three hours.
It takes a strong protective covering to protect the electronics from the many hazards a turtle can encounter, such as: constant exposure to salt water, impact from floating debris, and scraping against underwater rock ledges. They also measured her and took a blood sample to complete their survey. The transmitters, which cost about $3,500 each, should last for up to two years.
Researchers will use satellite telemetry information provided by the small transmitter that will be attached to the top of the turtle's bony shell. This isn't the first time the transmitters have been attached to the threatened sea turtles.
"We put five transmitters on loggerheads last year - - two here , and three on the west coast of Florida and have had no problems at all," said Barbara Schroeder, the national sea turtle coordinator with the National Marine Fisheries Service and a member of the research tagging team. "All five are still transmitting -- 12 to 13 months now -- very different from the green turtles."
She said green turtles seem to get beneath underwater rock ledges, scraping the antenna off and rendering the units unable to transmit to the satellite.
Finding the turtle on the long beach was not an easy task. In a process more similar to a night military reconnaissance patrol, students from the University of Central Florida (UCF) scouted a 25-mile section of beach using all-terrain-vehicles (basically a four-wheeled motorcycle known as ATVs) -- the headlights shielded with red plastic filters to avoid startling nesting turtles or attracting hatchlings. Driving slowly on the sand at the water's edge, they look for a turtle track. When a single turtle track is found, they dismount, and low-crawl up the beach to avoid startling the turtle.
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| Loggerhead turtle, with satellite transmitter attached, makes her way back to the Atlantic on the Florida coast. Photo by Tom MacKenzie, USFWS. Aug. 20, 1999. |
At 3:00 a.m., Karen Frutchey, a biotech assistant at the University of Central Florida, Orlando, Fla., points out a fresh turtle track.
"See how she pushed back here, leaving tracks that look like alternating comma marks," said Frutchey. "If you go out on the beach in the morning, you should be able to see it a lot better, as the shadows will be good. That's why we do our nesting surveys at sunrise with our ATVs, because the shadows are really good and the tracks aren't bleached out by the sun, so you can tell which way she came up and which way she went down."
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| Florida media witness the loggerhead turtle with satellite transmitter return to the sea near Melbourne Fl., Aug. 20, 1999. Photo by Tom MacKenzie, USFWS. |
In the moonlight, the marine biologists use their extensive knowledge of sea turtles to figure out if the turtle is a good candidate for tagging. They look for overall health conditions and how far along they are in the egg-laying process. They call the base, a beach house on Melbourne Beach, with a hand-held radio or a cell phone, giving the location of the potential tagging candidate. The "box crew" takes the bulky box on the back of a pick-up truck to the turtle, driving to the closest beach access trail, then carries the box to here the turtle is laying its eggs.
Then they wait.
When the turtle finishes covering her nest and begins her crawl to the sea, they carefully place the topless and bottomless plywood box over the turtle. This allows them to work on the turtle, then let the resin-coated fiberglass strips dry. The importance of the turtle is paramount in everyone's minds throughout the synchronized process.
"This is a large predator of the marine and estuary ecosystem," said Dr. Llew Ehrhart, director of the UCF Marine Turtle Research Group. "They have a role of regulating prey species and stabilizing the system to keep things from fluctuating wildly."
Llew and the students take on this mission with fervor. At 11:00 p.m., Llew can be found hunched over an ATV, tightening and oiling its chain for the night's patrol. Because after the satellite tagging effort wrapped up for the night, the University of Central Florida students still have to do their regular population survey, counting the nests in the dawn light using the tell-tale turtle tracks.
People have learned a lot about turtles, thanks to this type of research, but there is still is much to learn.
Through a Migration-Tracking Education Program, the Caribbean Conservation Corporation's Sea Turtle Survival League (STSL) hopes people take a greater interest in the plight of threatened and endangered sea turtles. In addition to extensive background information and photos of sea turtles, the STSL web site includes maps depicting the most recent migratory movements of nearly a dozen turtles being tracked around the southeast United States, Bermuda and the Gulf of Mexico.
Scientists involved in the studies offer regular reports, and an on-line bulletin board allows visitors to the web site to submit questions to participating researchers. For teachers wanting to incorporate the program into their classroom curriculum, the STSL offers a free educator program and 40-page Educator's Guide, which will be mailed to those requesting a copy. Destiny, the loggerhead that was tagged on August 20, 1999, got her name from Sakona Ly of Orlando, Florida, through an Internet-based naming contest with the group.
"In more than four decades, this Internet-based education program has been the Sea Turtle Survival League's most successful attempt ever to reach the public with accurate and fun information about sea turtles," said David Godfrey, executive director for the Caribbean Conservation Corporation. "Through the Sea Turtle Survival League's education program, thousands of people around the U.S. and the world, especially school children, can follow the migrations of sea turtles and learn about them, the threats they face and how to take part in helping to ensure their survival."
While great strides have been made in the U.S. to protect these rare and wonderful creatures, other countries still allow turtle eggs to be harvested, reducing the chance for a species comeback. It will be an international struggle to convince people in countries that are in economic straits to change how they have used turtles in the past and to lean toward conservation.
The satellite tracking research will help provide a factual basis for policy decisions that may have a huge impact on the loggerheads, the greens and the other magnificent threatened and endangered sea turtles.
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After being fitted with the transmitter, Destiny is released in the glare of the sunrise. Early rising media are on hand to capture the event. In the first three days after she laid her eggs and had the transmitter attached to her shell, Destiny has traveled more than 260 kilometers (160 miles), and in three months, swum more than 2,000 kilometers (1,240 miles) into the Caribbean.
The nights have turned cool now, even on the balmy Florida beaches.
Destiny, the sea turtle that first struggled against the odds to lay her eggs, is now back in her ocean home and is not expected to return to nest on the sultry Florida coast for two to three years. But in completing her journey, she may be helping people come up with innovative ways to help her species survive.
Release R99-087
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