Two SCA interns comb the beach for sea turtles
By Johna Strickland, The Tribune Georgian
Sarah Rose pulls up the reed marking where the sea turtle laid her eggs 77 days ago in the sands of Cumberland Island’s beach. She wiggles at least one hand into a latex glove and commences digging.
Within two inches the rain-packed sand gives way to loose sand churned by dozens of loggerhead turtles scrambling from their eggs to the sea. About 18 inches down, her fingers strike the leathery shells. She hauls mounds of sand and eggshells to the surface, dumping them into a sifting box.
“If you like to play in the sand, this is a good job,” said biologist Doug Hoffman as prepared to burrow into another nest.
When she hits hard sand again, that’s the bottom of the nest.
Hoffman shakes the sand out, leaving a collection of busted shells, unhatched eggs and, occasionally, a hatched turtle that died in the nest. He and Rose tally up each category and record it in a binder.
Hoffman buries the shells in the dunes, and then they load into the truck. Rose reads off the next set of coordinates; Hoffman drops the truck into gear and the Cumberland Island turtle patrol heads out.
A day at the beach
From May to October, Hoffman and his interns traverse the 18 miles of Cumberland’s beach daily. Two interns from the Student Conservation Association begin the summer and work through August. Rose and her fellow intern, Amanda, arrived in early August and will stay until October ends. They live on the island in a house owned by the National Park Service and each has one day off a week.
Rose, a 2010 biology and environmental studies graduate of East Stroudsburg University, studied sea turtles in 2009 at Canaveral National Seashore.
“I had to do an internship for my environmental studies major, so I thought I’d find a really, really awesome one,” she said, adding she now plans to study sea turtles in graduate school.
Their day starts at 6:30 a.m. in a truck loaded with buckets, pieces of wire fencing, stakes, gloves, vials and more gear.
On Tuesday’s patrol, Hoffman and Rose worked together while Amanda prepared to leave the island for a trip home to Wisconsin. At the road to Dungeness, Hoffman resets the trip odometer and drives south. Rose gives him the mileage to the first nest they will check or excavate and its number.
Sea turtles begin coming ashore to nest in May. Depositing an average of 110 eggs, each female digs about six nests, the final one by Aug. 14, Hoffman said.
In May, the interns watch for crawl marks from a likely 300-pound female loggerhead. One or two green and leatherback turtles nest on Cumberland each year. If the trail ends, they mark it as a false crawl; Cumberland has had 296 false crawls since May.
If they can trace the tracks to a nest, they assign it a number, log the coordinates using a global positioning system and record how many miles they drove from Dungeness.
They pound a numbered stake near each nest and tack a piece of wire fencing over it to protect the eggs from hogs, raccoons and armadillos hunting a snack.
“It’s like Christmas that time of year because you never know what you’ll find,” Hoffman said of May.
For the 60 percent of nests built too close to the tide line, they unearth the eggs and move them toward the dunes. Though some argue against altering a turtle’s selection, Hoffman said the hatch success rate varies by two or three percentage points.
“So that tells you by moving them, you’re not really impacting them as far as hatching,” he said.
Out of each nest, they collect one egg for a genetic study conducted by Brian Shamblin, a doctoral student at the University of Georgia.
“He just takes a little piece of the shell and tests it,” Rose said.
From the scrap, Shamblin determines the eggs’ origin, and he can track that female’s other nests by matching the data. Some females choose Cumberland to hold more than one nest as they traverse the coast, dropping eggs every 12 to 14 days.
“That’s how we know we’ve got mother-daughter pairs,” Hoffman said. “… You’re not going to cause the extinction of the species by taking one egg.”
In 35 to 40 years when this year’s crop of daughters reaches sexual maturity, some may return to nest.
Most years, Cumberland hosts approximately 250 nests. This summer, the interns and Hoffman have recorded 479 nests with more than 37,000 eggs with 775 emergences. The majority may bust out at one time with a few stragglers or leave in groups during a few days.
“They’ll hatch one at a time, then hang out and wait for the sand to cool,” Rose said. “… You never know.”
The hatchlings depart in dark hours, crawling past the beach morning glories for dozens of yards until they reach the surf.
On patrol
At the southern tip, Hoffman and Rose find a stranded sub-adult loggerhead on Tuesday’s patrol. They measure, photograph and scan the carcass for an identification chip but the turtle has been dead for so long that little more than the carapace – or shell – remains. If it were recently deceased, Hoffman would perform a “spontaneous necropsy” on the beach to determine cause of death.
“It’s easy to tell if you know what you’re looking for,” he said, adding damage from a boat, illness or drowning would be evident.
To date, 115 turtles have washed ashore on Georgia’s coast this year.
With the stranding recorded, Hoffman and Rose get back to checking the nests laid at least 50 days ago. At each stop, Rose or Hoffman gives the nest a look to determine if any hatchlings have emerged yet. They check for tracks left by little flippers and a disturbance in the sand.
If they see activity from ghost crabs – the eggs and turtles’ biggest predator at present – Rose records it on the nest’s card in the binder. Signs of a hog for more than two or three days warrants a visit for Hoffman. He arrives at dusk, sets up and waits for the hungry hog to arrive, then shoots it. Since Hoffman arrived in 2006, there have been two hog degradations.
“I’ve got a reputation to maintain,” he said.
Nests hatch at about 60 days, Hoffman said. In warmer weather, incubation speeds up to 45 or 50 days. With record highs this summer, Hoffman predicts the turtles will be predominately female. In the middle 20 days of incubation, if the temperature surpasses a certain degree, the embryos will be mostly female. Below that temperature, mostly male. At a moderate degree, the nest will produce a mix of the sexes.
The morning hours slip by: drive, stop, check, drive, stop, excavate. For nests seven days past emergence, Rose and Hoffman dig up the shells. Sometimes they find roots, which can grow through an egg and disrupt the embryo.
“We would really hate to get them out too early,” Rose said of the seven-day wait. “… You get to know these nests on a personal basis,” Rose said.
Hoffman agreed, “You just get a feeling when you’re coming up on one.”
On Tuesday, they excavated 11 loggerhead and one green turtle nests. At one recently emerged nest, Hoffman and Rose discover a live turtle – about the size of a cookie that fits in a palm – on the sand. He gets a free ride to the ocean as the wind whips his flippers into the air like kites. He only lifts his head and sand has crusted near his eyes. He drifts into the tide without making an effort to swim.
“He’s probably fish food,” Rose said.
According to the Georgia Sea Turtle Center on Jekyll Island, just one in 4,000 baby turtles will live to adulthood.
By noon, they arrive back at the field office where they wash down the truck, unload gear and begin the task of entering data into their records and seaturtle.org, a website where data from East Coast sea turtle nests are collected.
Rose cooks breakfast and makes a recreational trip to the beach. Hoffman attends to his other duties.
“This is what we do every day for six months,” Hoffman said.