Turtles Are Casualties of Warming in Costa
Rica
By Elisabeth Rosenthal, New York Times
Playa Grande, 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.
“It’s happened really fast — we have no
rain, but water pouring in from the ocean,”
said Adriana Miranda, 30, the manager of a
local hangout that serves beer and rice and
beans.
Beachside tables have been removed because
rising tides have destroyed the restaurant’s
concrete terrace and uprooted shading trees
there. 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. “The squeezing of the beaches where
turtles nest is going to be a big problem,”
said Carl Safina, head of the Blue Ocean
Institute, a conservation group.
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 140 yards back from the
current high-tide line protected from
development. Beachfront property owners,
many of them foreigners with vacation homes,
demanded hefty compensation.
Arguing that the government cannot afford
the payouts, President Óscar Arias has
instead proposed protecting the first 55
yards, and allowing about 80 yards of
somewhat regulated mixed-use development to
the rear. But Costa Rica’s leading
scientists have protested that the new
boundaries will lead to “certain
extinction.”
Turtles will not nest if there are lights
behind the beach, Mr. Drews said, and those
first 55 yards will be underwater by
midcentury.
“Turtles will have to find their way between
the tennis courts and swimming pools,” he
said dryly.
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. |
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In Playa Junquillal, Costa Rica, so-called leatherback boys carry newly hatched turtles in baskets to the ocean, where the freed turtles make a dash for the water. |
