A Wilderness Ecosystem in Collapse

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.

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

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