Wednesday, January 6, 2010

A troubling time for sea turtles in the Pacific; Populations devastatedby global warming and coastal development. USA,

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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," she said. "That is part of the appeal."

But haphazard development, in tandem with higher 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 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 Alvaro 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 unusually, 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 Fahrenheit), the gender balance shifts to females, Mr. Drews said, and at about 32 Celsius (90 Fahrenheit), they are all female. Above 34 Celsius (93 Fahrenheit), "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, 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 Fahrenheit), which will yield both genders.

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 "baulas," 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 about 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 50 meters, or 164 feet, above the high-tide line are now frequently underwater.

In different circumstances, the beaches could gradually extend backward as the sea level rose. But along much of Costa Rica's Pacific coast, the back of the beach is now filled with hotels, restaurants and planted trees, giving the sand no place to go.

In Playa Grande, the turtle issue has pitted environmentalists against developers and the national government. To ensure a future for the leatherbacks and the national park, biologists wanted a large section of land extending about 130 meters behind the current high-tide line protected from development. Owners of beachfront property, many of them foreigners with vacation homes, demanded hefty compensation.

Arguing that the government cannot afford the payouts, President Ascar Arias has instead proposed protecting the first 50 meters, and allowing about 73 meters of somewhat regulated mixed-use development to the rear. But the leading scientists in Costa Rica have protested that the new boundaries would lead to "certain extinction."

Turtles will not nest if there are lights behind the beach, said Mr. Drews of W.W.F., and those first 50 meters would be under water by 2050.

Source Citation
Rosenthal, Elisabeth. "A troubling time for sea turtles in the Pacific; Populations devastated by global warming and coastal development." International Herald Tribune 17 Nov. 2009. Military and Intelligence Database. Web. 6 Jan. 2010. .

Gale Document Number:CJ212145835

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