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By MARLA CONE, LA Times Environmental Writer
ADAK
ISLAND, Alaska--There are few places on Earth that have
changed so much, so fast as the narrow arc of islands where
the Pacific Ocean greets the Bering Sea.
The
Aleutian Islands are in the middle of nowhere. No tourists,
no cruise ships, no chartered fishing trips, no quaint country
inns. On a quiet day, when the turbulent seas and legendary
winds are still, you can hear a killer whale breathe.
But
look and listen more closely. Something is missing.
Where
are the sea lions, fat and happy, napping on the rocks and
barking at their pups? And the furry sea otters crunching
on urchins? What became of the ample king crabs and shrimp,
and the schools of silvery smelt? And where are the lush
undersea forests of kelp that provided food and refuge for
fish?
As sudden and savage as an Arctic storm, some mysterious
phenomenon has transformed this spectacular archipelago
of more than 1,200 miles in just a handful of years.
A vast
subarctic ecosystem is collapsing. No one knows why.
The sudden changes in the Gulf of Alaska and the Bering
Sea have inspired an eclectic team of men and women to try
to solve an extraordinary environmental whodunit. Virtually
alone in a forbidding wilderness closer to Siberia than
to Anchorage, they have been divebombed by eagles, bitten
by otters, buffeted by 70-mph winds, rattled by earthquakes
and lost in storms. And each year they return for more,
drawn back by the Aleutian paradox. If this rugged, remote
ecosystem is collapsing, can any place on Earth be safe?
Jim Estes, a marine ecologist at the U.S. Geological Survey
in Santa Cruz, has traveled to the Aleutians for the last
30 summers, studying what once was the world's largest and
healthiest population of sea otters. Three summers ago Estes
realized that the otters had virtually disappeared while
he watched.
There were no bodies to dissect, few clues to decipher.
The otters aren't starving. They aren't sick. They have
simply vanished.
Throughout
the Gulf of Alaska and probably the Bering Sea, too, the
balance of prey and predator has been upended, a transformation
so extreme it's called a "regime shift." Waters
once brimming with seals, otters and king crab are now dominated
by sharks, pollock and urchins. Virtually no creature remains
untouched.
"You
just can't grasp how different things were 10 years ago,"
said Estes during a recent expedition. "No one has
ever seen a decline of this magnitude in such a short period
of time over such a large geographic area."
Piece by piece, over the last three years, scientists have
started to solve the puzzle. Clues point toward something--almost
imperceptible--that happened in the ocean in 1977. But the
answers are more disturbing than satisfying, more elusive
than conclusive. It seems the ocean's chain of life is actually
a fragile silken web. If you remove a strand, the whole
thing unravels. And it may never be whole again.
An
Unprecedented Population Loss
Tim
Tinker is swathed in a bulky orange survival suit, hanging
from the bow of a 25-foot boat as it hugs the rugged shore
of Adak Island.
A brutal
storm has just ended, leaving August skies crisp and clear.
Adak's mountains, set against a blue satin sky and fog as
white as cotton balls, are draped with a luxuriant fleece
blanket of moss. The green shines so brightly it seems as
if it could glow in the dark. Overhead, a bald eagle soars,
and black and white puffins skim across the surface of the
sea, their orange webbed feet splashing the 40-degree water.
From
his perch on the bow, Tinker lifts his binoculars, training
them on rocky reefs. For the ninth straight year, he is
counting the Aleutians' sea otters for an annual survey.
He scans a reef, lowers his binoculars and turns toward
the stern of the boat, holding up a single finger clad in
ragged wool gloves.
Iris Faraklas, a research assistant, dutifully makes a notation:
One otter.
An hour into the survey, Tinker, a marine mammal biologist
at Santa Cruz, and his colleague Brian Hatfield have counted
only five otters and two harbor seals.
"Back
in the old days, in the early '90s, we probably would have
seen 500 otters by now," said Estes, as he pilots the
boat around submerged rocks and into foggy inlets. "Now
we go miles and miles without seeing even one."
This day, they will survey 200 miles of coast, finding only
171 adult otters and 29 pups.
If
sea otters dream, they are surely dreaming about a place
like Adak Island, in the middle of the Aleutian chain. There's
plenty of food. Plenty of sanctuary. But only one otter
per mile.
In the
1980s, as many as 100,000 otters inhabited the islands.
Today, only about 6,000 remain, according to aerial surveys.
Between 1992 and 2000, the population dropped by 70%, a
rate of decline that researchers say is unprecedented for
any mammal population in the world.
"What's
really horrifying is that the Aleutians have always been
considered the stronghold of otter populations," said
Rosa Meehan, who heads the marine mammal office of the U.S.
Fish and Wildlife Service in Anchorage.
"At
one time, 80% of the world's population of sea otters were
out there," Meehan said.
Now,
the wildlife agency has declared otters a candidate for
endangered-species protection, although only in western
Alaska.
In 1995,
when they began to notice the signs of a population decline,
Tinker and Estes, who specialize in otter behavior and population
biology, at first looked for signs of disease, famine or
reproductive troubles. They found none.
For a couple of years, as the decline steepened, they were
baffled. If thousands of otters had died, where were the
bodies?
Then
it dawned on Tinker: Perhaps the animals were being eaten.
By killer whales.
Estes
was disbelieving at first. For orcas, which are voracious
predators, otters are little more than hairballs. Snack
food for a killer whale.
Still,
Estes remembered spotting an occasional killer whale lurking
close to shore over the years. And it did seem odd that
most of the surviving otters were in a small lagoon on Adak--unreachable
by killer whales. He decided to test the theory. In 1997,
Estes and Tinker packed up a dead otter on Amchitka Island
and flew it to California, where a colleague ground it up
in a giant blender, calculated its calorie load and compared
it with how many calories a killer whale consumes.
It turned
out that fewer than four whales--3.7 to be exact--could
have eaten 40,000 otters in five years.
"We
were absolutely blown away," Estes said.
But
orcas had lived in harmony with otters for thousands of
years on the Aleutians. Why, all of a sudden, were they
preying on them so heavily?
To find the answer, biologists simply had to follow the
food chain.
Orcas
customarily feed on sea lions and seals, which are packed
with high-calorie blubber. But the population of Steller
sea lions, the world's biggest sea lions, took a sharp dive
in the late 1980s. Harbor seals also declined at a similar
rate.
By 1992,
otters were the only plentiful marine mammals left in Aleutian
waters. The orcas, in their hunt for calories, apparently
had been forced to switch prey.
The
effects cascaded rapidly down the food chain.
With
far fewer otters around to eat them, sea urchin populations
exploded--increasing eight-fold within a few years. As many
as 100 of the spiny green creatures now cover each square
foot of ocean floor around the Aleutians.
The urchins, in turn, ate the kelp.
In 1993,
kelp forests were 20 feet deep and so thick they clogged
the engines of Brenda Konar's dive boat. "Now the only
kelp you find is the stuff right by the shoreline, and it's
maybe only three feet deep," said Konar, a biologist
with the School of Fisheries and Ocean Sciences in Fairbanks.
When
the leafy undersea forests vanished, so did many of the
rockfish, snails, starfish and other creatures that use
the kelp for food, shelter and breeding grounds. Some local
seabirds, mainly puffins and kittiwakes, also are hurting
from lack of fish.
The
Aleutians offer proof that one small ecological change can
move like a tsunami throughout the entire ocean realm. Yet
the snarl in the food web had to begin somewhere. Where,
scientists wondered. And, even more important, who--or what--did
it?
A
Tough Place for Nature Studies
In
Alaska, August is prime tourist season. Fishermen from around
the world flock to its coastline and lug ice chests home
packed with salmon and halibut. But not in the Aleutians.
Hardly anyone ventures here.
It's
a four-hour flight from Anchorage to Adak, and from there,
it's 38 hours by ship to Attu, which sits 1,200 miles off
the mainland, on the far western edge of the chain, next
to Russia.
It's
not easy to chronicle nature in a place so inaccessible,
so forbidding.
For a month each year, the research team travels to Adak
and Attu, counting otters and collecting fish, urchins and
mussels for tests. They work at sea from daybreak to nightfall,
taking advantage of summer daylight, which in this part
of the world lasts 15 hours. Along shorelines known to be
treacherous to navigators, Tinker, Hatfield and Estes logged
a thousand miles this August in their 25-foot boat.
Part
seaman and part scholar, Estes over the last three decades
has weathered just about anything this extreme environment
can offer.
One August on Attu Island, Estes and two colleagues almost
died when their boat engine failed and an unexpected winterlike
storm hit. The three hiked for nearly three days, covering
maybe 100 miles. A student researcher--a triathlete--suffered
hypothermia and Estes was forced to consider abandoning
him to die. They found their way back to camp through more
luck than skill, Estes recalls.
No
wonder events on this archipelago go largely undetected.
In 1986, the largest earthquake recorded in North America--a
magnitude 8.0--struck the Aleutians. Hardly anyone was around
to notice.
But
proximity to people is not always the best indicator of
environmental damage. There are no clear-cut forests. No
rows of red-tiled roofs. No industrial smokestacks. This
wilderness still looks as nature intended. And there lies
the paradox.
"Anybody
that comes to Alaska says 'My God, this place is beautiful!'
They look at the puffins and see a bald eagle and it's a
pristine, incredibly breathtaking place to be," said
Bruce Wright, a division chief at the National Marine Fisheries
Service in Alaska. "But without spending time out there
doing long-term monitoring to understand the changes that
are taking place, that's just a superficial look."
It was
almost a fluke that Estes and his team witnessed the ecological
changes here. Ironically, Estes initially was drawn to the
Aleutians because of their bounty of life. He was trying
to figure out why California's otters were hurting while
Alaska's were thriving. Now he's haunted by a suspicion
that other ocean realms could be undergoing similar dramatic
changes--it's just that no one is around to watch.
1977
Event May Have Been Trigger
On
the Pacific side of Adak Island, needle-sharp spires crafted
by ancient lava jut out from the sea--sentries guarding
the shoreline. Everything about these volcanic islands seems
eternal, as if you could return every year and nothing would
ever change.
But
the Aleutians are a dynamic place, ever-changing. Fog shrouds
the islands one instant and retreats the next. Hurricane-force
squalls descend with little warning. The environment of
the Aleutians, however, isn't supposed to be as capricious
as its weather. Ecosystems normally evolve slowly.
"I
have not come across any other example of such a total flip-flop"
of an ocean environment, Wright said.
Ecological
shifts as sudden and sweeping as the ones in the Aleutians
usually can come only from human interference, said David
Lindberg, an evolutionary biologist at UC Berkeley. If the
shift were natural, animals and plants of the Aleutians
would have evolved with some defensive strategies, he said.
"We're
incredible, as a species, at speeding up changes,"
Lindberg said.
Scientists are exploring many factors--global warming, overfishing,
pollution--that might have played a role in the Aleutians'
misfortunes. Looking back, they theorize that the key event
may have come in 1977, when a sudden warming--just two degrees
Celsius--in the average temperature of the Gulf of Alaska
was recorded.
The
Arctic has been especially vulnerable to climate change,
which many scientists believe is caused in part by worldwide
burning of fossil fuels and production of greenhouse gases.
Although
they cannot know for sure, researchers believe the chain
of events was most likely this:
Warmer water caused plankton--short-lived and ultra-sensitive
to temperature changes--to disappear. Tiny copepods and
krill probably followed quickly.
The shrimp and crab, along with smelt fishes such as capelin
and herring, would have vanished afterward, deprived of
their food, to be replaced by an explosion of cod and pollock.
Once-thriving shrimp and crab fisheries collapsed in the
late 1970s while the new species attracted large fishing
trawlers that descended on Alaska, harvesting millions of
tons of pollock and cod a year for American and Japanese
consumers.
By the
mid-1980s, the problems spread to young mammals.
The
decline of the smelt fishes probably triggered the collapse
of the seal and sea lion populations, say marine mammal
biologists, including Kathy Frost of the Alaska Department
of Fish and Game. The smelt are high in fat, and without
them, baby mammals might not find enough calories to survive
the winters.
But
salmon like warmer water. Their populations have increased,
drawing sharks, which feed on salmon and--at times--on seals
and sea lions.
All of a sudden, the Aleutians had turned into a predator
pit, unsafe for marine mammals.
So far,
the rest of Alaska has escaped the regime shift, presumably
because waters elsewhere around the state have different
ocean circulation patterns and have not warmed.
Commercial
fishing of pollock and cod may be exacerbating the food
shortage for the mammals. In July, a federal judge ordered
the U.S. government to ban commercial fishing around the
Aleutians to protect endangered sea lions. Before the ban,
nearly every fish filet sold at U.S. fast-food outlets had
come from Aleutian waters.
Commercial
fishermen in Alaska say it is unfair to blame them. Pollock
are still plentiful and they had never harvested the capelin
and other smelt important to sea lions. But environmentalists
argue that the huge trawling operations are now taking the
only food left for the animals.
Scientists
are only beginning to try to figure out what role pollution
might be playing in the ecological shift.
Pollutants
have drifted to the Aleutians from thousands of miles away.
Bald eagles that never leave the islands are contaminated
with DDT, a pesticide apparently never used here. Air and
ocean currents in the North Pacific move in a clockwise
pattern, which means pollutants from Asia move toward the
Aleutians.
And
the U.S. military, which recently shut down a base on Adak,
left behind PCBs, polychlorinated biphenyls, which can harm
animals' reproductive and immune systems. Estes' team was
shocked to learn that otters on Adak are twice as contaminated
as ones in California and 10 times as contaminated as otters
elsewhere in Alaska.
"It's
such a land of contrasts here," said Walter Jarman,
an expert on pollutants from the University of Utah. "There's
something so contradictory about a place that is this beautiful
and remote and contaminated," he said as he stood next
to a pile of unrecognizable military debris in a grassy
field on Adak. "We have an unfortunate laboratory here."
Still,
Jarman suspects that the military pollution has not been
the driving force behind the otter and sea lion problems,
since the population crash has been documented even on islands
with no PCBs.
"My
gut feeling is that it's not connected," he said. "But,
from the very beginning in the Aleutians, we've been wrong
a lot."
The
Aleutians are so unpredictable that scientists may never
be able to unravel all the biological interactions and prove
or disprove their theories about how the food web got tangled.
"It
drives people crazy when you don't give them a straight
answer," said Frost of the state wildlife agency. "But
it's an unbelievably complicated place, and biology is not
a very clean science. Animals are like people. There is
never one factor at play. . . . Sometimes you poke along
and poke along and all of a sudden, the pieces fall into
place."
Some
experts say the ocean may be shifting back, favoring the
marine mammals again instead of the sharks and pollock.
If it does, Estes and his team will be there to chronicle
it.
But
even if all the elements--the forage fish, the otters, the
sea lions, the kelp--were to return, these islands will
never be the same. Like marble chips in a kaleidoscope,
they would fall in different patterns.
"I'm
not going to see it recover in my lifetime," Estes
said.
From
the three decades of snapshots he carries in his head and
the three decades of data stored in his computer, Estes
knows this wilderness is no longer unspoiled. But, when
he steers the boat past a delicate waterfall, knowing few
humans will ever see it, the Aleutians still feel wild to
him. And that sensation, decidedly unscientific, gives him
hope. He will be back next year.
A Shifting Balance
Alaska's
remote Aleutian Islands have always been an oasis for marine
life. But this subarctic ocean ecosystem has undergone a
dramatic transformation in recent years.
Waters
that brimmed with marine mammals, crab, shrimp, forage fish
and kelp are now dominated by urchins, sharks and groundfish
like pollock that do not provide a high-calorie diet for
marine animals and birds. Sea lions, seals, otters, shrimp
and crab have almost disappeared, and some seabird populations
are declining.
Scientists
speculate that global warming is the culprit. Gulf of Alaska
temperatures have risen by 2 degrees Celsius in the past
20 years. Also, intensive commercial trawling is reducing
fish populations.
Sources: National Marine Fisheries Service, U.S. Geological
Survey
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