"Turtles Are Casualties of Warming in Costa Rica"

From the New York TImes:

PLAYA GRANDE, Costa Rica — This resort town was long known for Leatherback Sea Turtle National Park, nightly turtle beach tours and even a sea turtle museum. So Kaja Michelson, a Swedish tourist, arrived with high expectations. “Of course we’re hoping to see turtles — that is part of the appeal,” she said.

But haphazard development, in tandem with warmer temperatures and rising seas that many scientists link to global warming, have vastly diminished the Pacific turtle population.

On a beach where dozens of turtles used to nest on a given night, scientists spied only 32 leatherbacks all of last year. With leatherbacks threatened with extinction, Playa Grande’s expansive turtle museum was abandoned three years ago and now sits amid a sea of weeds. And the beachside ticket booth for turtle tours was washed away by a high tide in September.

“We do not promote this as a turtle tourism destination anymore because we realize there are far too few turtles to please,” said Álvaro Fonseca, a park ranger.

Even before scientists found temperatures creeping upward over the past decade, sea turtles were threatened by beach development, drift net fishing and Costa Ricans’ penchant for eating turtle eggs, considered a delicacy here. But climate change may deal the fatal blow to an animal that has dwelled in the Pacific for 150 million years.

Sea turtles are sensitive to numerous effects of warming. They feed on reefs, which are dying in hotter, more acidic seas. They lay eggs on beaches that are being inundated by rising seas and more violent storm surges.

More uniquely, their gender is determined not by genes but by the egg’s temperature during development. Small rises in beach temperatures can result in all-female populations, obviously problematic for survival.

“The turtles are very good storytellers about the effect of climate change on coastal habitats,” said Carlos Drews, the regional marine species coordinator for the conservation group W.W.F. “The climate is changing so much faster than before, and these animals depend on so much for temperature.”

If the sand around the eggs hits 30 degrees Celsius (86 degrees Fahrenheit), the gender balance shifts to females, Mr. Drews said, and at about 32 degrees (89.6 Fahrenheit) they are all female. Above 34 (93), “you get boiled eggs,” he said.

On some nesting beaches, scientists are artificially cooling nests with shade or irrigation and trying to protect broader areas of coastal property from development to ensure that turtles have a place to nest as the seas rise.

In places like Playa Junquillal, an hour south of here, local youths are paid $2 a night to scoop up newly laid eggs and move them to a hatchery where they are shaded and irrigated to maintain a nest temperature of 29.7 degrees Celsius (85.4), which will yield both genders.

On a recent night, Dennis Gómez Jiménez, a 22-year-old in a red baseball cap and jeans, deftly excavated the nest of a three-foot-wide Olive Ridley, one of the smaller sea turtle species. The turtle had just finished the hourlong task of burying 100-plus eggs and then lumbered back into the water.

One by one, Mr. Jiménez placed what looked like table tennis balls into a plastic bag and transferred them to an ersatz nest he had dug in a shaded, fenced-off portion of sand that serves as a hatchery. Sandbags are positioned to protect against tides that could rip nests apart.

When the turtles hatch, in 40 to 60 days depending on the species, they are carried in wicker baskets to the ocean’s edge and make a beeline for the water. Gabriel Francia, a biologist who oversees the youths, known locally as the “baula” or leatherback boys, likens their work to delivering an endangered infant by Caesarean section.

“In some ways we’re playing God — this is a big experiment,” he said. The long-term hope, he said, is to build a robust turtle population that will slowly adapt by shifting to cooler, more northern beaches or laying eggs at cooler times of the year.

Worldwide, there are seven sea turtle species, and all are considered threatened. (Turtle populations in the Atlantic have increased over the last 20 years because of measures like bans on trapping turtles and selling their parts.)

The leatherback is considered critically endangered on a global level. Populations are especially depleted in the Pacific, where only 2,000 to 3,000 are estimated to survive today, down from around 90,000 two decades ago. Cooler sands alone will not save them, given the scope of the threats they face. At Playa Junquillal, markers placed a decade ago to mark a point 55 yards above the high tide line are now frequently underwater....

In a country where turtle eggs are traditionally slurped in bars from a shot glass, uncooked and mixed with salsa and lemon, biologists are also promoting cultural change.

“Of course 25 years ago, you went out with your friends or family and dug up the eggs,” said Héctor García, 42, shopping at the Junquillal market. “It was a tradition. They are delicious, cooked or raw.”

Today egg collecting is illegal in Costa Rica, but poaching is still common in many towns. It is frowned on at Playa Junquillal, where the five baula boys, with their piercings and baseball caps, patrol for poachers and are idolized by many younger children. Dr. Francia, the biologist, has also invited local families to watch the babies being released. “There were a lot of people who had eaten eggs but never seen a turtle,” he said.

Leatherback Turtles Following Jellyfish to New England

The site Turtle Protection, Leatherbacks have a range up to the Arctic Circle, and "nest on the tropical beaches of the western Atlantic from the Caribbean northwards". Perhaps these were nesting females and that's the difference. They apparently don't usually come near the shore in that area. Jellyfish are their primary food.

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From gpsdaily.com:

University of New Hampshire researchers have tagged one male and two female leatherback turtles off Cape Cod. They are the first free-swimming leatherbacks ever tagged in New England.

The 700 - 800-pound leatherback turtles, an endangered species, were tagged July 17, 26 and 29 with GPS-linked satellite tags that transmit nearly real-time tracking data, allowing scientists to better understand these elusive, highly migratory giants to enhance their survivability.

"We investigators spent 20 years attempting to learn about these animals on the high seas and temperate ocean waters, with only slow progress," says UNH research associate professor Molly Lutcavage, director of UNH's Large Pelagics Research Center...

And, says Kara Dodge, the UNH Ph.D. student leading the tagging effort, the turtles are cooperating. "It's leatherback craziness this year," she says, noting that warmer water temperatures have brought an abundance of jellyfish, the primary food source for leatherbacks.

The $5,000 GPS-linked satellite tags Dodge and her colleagues, including Andy Myers, a postdoctoral researcher in the Large Pelagics Research Center (LPRC), are attaching to the leatherbacks aim to fill the knowledge gap on these elusive swimmers.

The tags transmit depth, water temperature and location information daily via satellite, allowing researchers to gain much-needed insight into the movement patterns of the sea turtles. Dodge is also analyzing the data as it relates to oceanographic conditions and jellyfish distribution...

Dodge has tracked the male, who was tagged July 17 about eight miles offshore in Nantucket Sound, to south of an area called the Canyons, off the continental shelf. He has traveled about 1100 kilometers in less than two weeks. "He just took off," she says. "I think it's a speed record."

The females, tagged July 26 and 29 in Vineyard Sound just eight miles southwest of Woods Hole, are swimming at a more leisurely pace; the first female is about 250 kilometers from where she was tagged and the second female swam about 65 kilometers between Tuesday and Wednesday.

Leatherback turtles, which can weigh up to 2000 pounds and are warm-bodied, like bluefin tuna, are the largest living reptiles in the world. The most migratory sea turtle species, they travel great distances through a wide range of water temperatures and to great depths.

In the western Atlantic, leatherbacks travel from their nesting grounds in the Caribbean, northern South America, and southeast Florida to the productive foraging ground of Atlantic Canada. Leatherbacks typically come to the waters off Cape Cod from July through October although, says Dodge, "we've never known whether they're coming to forage or just passing through."

Previous tagging efforts by Dodge, Myers and Lutcavage have focused on leatherbacks that have been entangled in buoy lines of fishing gear...

Off shore and away from their nesting areas, leatherback turtles have no natural predators except sharks and killer whales; entanglement in fishing gear, ingestion of marine debris and injuries from boat propellers are the major threats to their survival.

"Understanding where they travel and how they use the water column will help us mitigate these human interactions," says Dodge. Emerging research indicates that climate change likely has a large impact on the leatherback population, as well...

The tagging effort will continue off Cape Cod through September; Dodge hopes to tag nine more leatherbacks. In addition to the National Fish and Wildlife Foundation, this work is supported by the National Marine Fisheries Service Northeast Regional Office and the Cape Cod Commercial Hook Fishermen's Association.