After the Ice

by Alun Anderson

  Why are the beluga whales silent except when they have great need or are in the safety of large numbers? The answer is easy to guess. It is a classic reaction to the presence of killer whales. When hunting, the killer pod listens carefully for prey but remains quiet to give no warning of their presence: only when they attack is there a sudden blizzard of underwater communication sounds. Then it is too late. The next underwater sound is that of crunching bones.

  Even bowhead whales may not be able to cope with killer whales. “They are quite large so you would think they’d be relatively safe from predation, but they seem to rely on sea ice as a means of reducing the risk of killer whale predation. That concerns me,” says Ferguson. To find out what happens when killers confront bowhead, he has been turning to the traditional knowledge of Inuit hunters, traveling around Inuit communities and collecting their stories and observations. A scientist might wait years to be at the right spot to see the two giant mammals confront one another, but Inuit have been out there observing nature and passing down stories for generations. “Hunters have pretty graphic descriptions of how the killer whales take the bowhead. Bowhead will stand and fight. They are not fast, but they are quite maneuverable,” says Ferguson. But it does not always go one way. “We have even an observation from hunters of a bowhead whale killing a killer whale in a confrontation.” From the scars in the tail flukes of bowheads, Ferguson thinks that killer whales often just try to harass the mother to slow her down while they are really after her smaller calf.

  The one advantage of all three of the ice-adapted whales is that they can more easily hide in very dense ice than can the killer with its enormous triangular fin. If the ice goes and killers arrive, Ferguson fears a “trophic cascade.” That happens when key species are taken out of a food web and the entire ecosystem structure begins to change uncontrollably.

  I ask Kovacs if there are other invaders we might expect to see. “You are going to have all of the big traveling animals. Anything that flies or swims is an efficient migrator and an efficient disperser,” replies Kovacs. “If you are traveling on air or in water, distance really isn’t a big deal. The cost of locomotion is so low. And for a large swimming whale or seal, distance is almost a nonissue. So they are going to move wherever there is food available for them. You have a lot of the large baleen whales moving north and now we are seeing blue whales in aberrantly high numbers in the last couple of summers, although that still means only between six and ten animals. But still, we are seeing them for the first time.”

  I’d seen a group of fin whales, with their long, sleek bodies and distinctive blow which clouds the air a few seconds before their dorsal fin breaks surface, moving up the east coast of Svalbard. That surprised me as these baleen whales’ usual home is much farther south. Kovacs confirmed that there are many fin whales around Spitsbergen now. “They are already on the move and they will take food that certainly could have been taken only by the bowhead whales just a decade or two ago. If they are up there and take in a large volume of food as these large animals tend to do, then you will have pressure on the Arctic dynamics,” she warns.

  Competition between residents and invaders comes partly down to life strategy, Kovacs tells me. Many Arctic species have “a slow and steady” life strategy. The Arctic is a place of great extremes and great variation year on year, with good years and bad years. One way to deal with that is to live for a long time and just breed whenever you can; the good years and the bad years will average out and in the end you’ll leave offspring to take your place.

  “The long-term winning strategy is to just do it slow and do it well,” explains Kovacs. “So you have only one baby every five or seven years in the case of a bowhead whale, but you live for two hundred years so you get there eventually. All these Arctic mammals are slow to get to sexual maturity but they live long.” The same is true for many birds of the Arctic. The tiny, little auk just lays one egg each year when able but lives for twenty or more years. It may not breed successfully for a few years but that is all part of the long-term success strategy.

  This conservative strategy works well in the old Arctic, but what happens when conditions improve and you are up against competitors that breed faster? “Slow and steady doesn’t work when you have a baleen whale coming up that can have a baby every year,” warns Kovacs. “Then there are more of them and they eat large volumes of food. That food would either have fed your young or would have been your food. The Arctic endemics aren’t going to be very good at keeping up with those other guys.”

  When I had been thinking about the future of the bowhead whale in the changing Arctic, my mind had focused on threats to its food supply of rich copepods along the ice edge as the ice vanished. I had not thought that the real threat might be competition from other whales coming up from the south.

  All over the Arctic invaders are pouring in. “Harbor porpoises have been seen in Spitsbergen for the last four years,” Kovacs tells me. “This has never happened before in history.” And on the other side of the Arctic, on Cooper Island off the north coast of Alaska, ornithologist George Divoky started to see horned puffins, which have no affinity with ice, arrive and then become regular breeders over the last decade. Now another puffin has shown up. “In the last couple of years, I have seen a few tufted puffins. That’s a true southern species that hasn’t been here before,” he told me.

  What about the less conspicuous creatures? Creatures that don’t swim or fly are just drifting to the Arctic if the currents head that way. “Blue mussels are back for the first time in a thousand years,” says Jørgen Berge of the University Centre in Svalbard.2 Blue mussels, a staple of Spanish and Portuguese cuisine, were common in Svalbard during the Viking age, when northern Europe was in the middle of the medieval warm period, but they had long since vanished. Now they have returned.

  Other creatures that are happy in warmer waters are also showing up. “We talked to fishermen who have been here for the past thirty years, and they hardly found any cod in the ’70s and ’80s,” says Berge. “We started to see some cod in the trawl hauls in late ’90s, now there is a really huge amount of big Atlantic cod. We see larvae of haddock we hadn’t seen before. Since we are living in the area where the main inlet of the water from the Atlantic Ocean comes into the Arctic, carrying huge amounts of eggs and larvae from southern species, there will always be a massive influx of potential new settlers. What has changed is that some seem able to settle and grow.”

  As southern invaders enter the Arctic, indigenous species might be expected to flee north into the cold Arctic sea, but as Kovacs points out, there is really nowhere to go. “You can’t just retreat northwards, because you fall off that coastal shelf into the deep Arctic Ocean.” Out in the deep, the seas are not productive and there is not enough to eat.

  As the boundary between the sub-Arctic and the Arctic moves north, and the seas warm, not all the invaders will be large or obvious. Up in the Arctic, it is too cold for many disease-causing bacteria and viruses to thrive. “The Arctic animals are really very much protected by cold. In a warmer environment, you will have pressure from introduced diseases and from introduced parasites. These potentially disease-carrying animals will thrive in a way they never have before,” worries Kovacs. “If you get a cut when you are working with the Arctic animals, you never worry about it, because they don’t carry anything. Whereas working in the southerly latitude, my God, you cut yourself when you are doing something with seals, you have to detox yourself, because you can end up in the hospital with blood poisoning. It is a totally different world.” It is a world that is coming to the Arctic.

  The deep northern seas will not be the final frontier for Arctic invaders. There is an even bigger different dimension to this mass movement of species that I had completely missed. The Arctic seas are not just a place that you can move into but are also a shortcut between the Pacific and the Atlantic oceans. I knew nothing of this possibility until I came across a paper3 published in 2008 in Science titled “
The Coming Arctic Invasion.” Two scientists warned that as the Arctic ice vanishes, “an even more dramatic interoceanic invasion will ensue.” Geerat Vermeij of the University of California at Davis and Peter Roopnarine of the California Academy of Sciences in San Francisco predict that many creatures from the Pacific Ocean will enter the Arctic and go on to successfully invade the Atlantic, transforming that ocean as well. The warming of the Arctic thus opens the gates for a transformation of the world’s oceans.

  “Dramatic” is definitely the right word for this interoceanic invasion. Why do these two scientists think it is going to happen? Not for the reasons you might expect. They haven’t been out collecting new creatures in the Arctic. Instead, they have looked at the great trends that have transformed the earth over many millions of years and from them they have predicted the future.

  Vermeij and Roopnarine both study ancient mollusks, which with their hard shells are easily preserved as fossils in layers of sediment laid down over millions of years. The two scientists say that the fossil record shows that creatures from the Pacific began to invade the Atlantic via the Arctic about 3.5 million years ago when the earth was warmer. The invasion ground to a halt with the arrival of the ice age when the Arctic froze up. Now with conditions warming again, the invasion can resume.

  I’d never heard of anyone making predictions about the near future based on events that happened millions of years ago, so I called Peter Roopnarine in his laboratory at the California Academy of Sciences and asked if this was the usual practice in paleontology. He laughed gently at my question. “No, not regarding climate change now,” he said, “but in the fossil record we often have periods of climate change. We’ve had many of them over millions of years, and we’ve also had barriers, whether of climate, oceans, or physical, being removed over time, so we have studied the invasions and migrations of the past.”

  To think like a paleontologist, you have to stretch your notion of time. “During the later Miocene era, just 10 million years ago, we had a climate optimum on the planet where conditions were very mild,” Roopnarine says, “then as we moved into the Pliocene, the planet became quite warm. During this warming, starting about 3.5 million years ago, species moved from the North Pacific to the North Atlantic, but by about 2 to 2.5 million years ago, we had a refrigeration of the northern hemisphere and migrations came to a more or less abrupt halt.”

  The imprint of those events of 3 million years ago can be seen in the Atlantic where descendants of the creatures that crossed from the Pacific still remain. Now, says Roopnarine, there are seventy-seven species with the potential to invade the Atlantic from the Pacific. And that is just the mollusks. But why should Pacific species be able to overrun the Atlantic?

  The answer turns out to be a familiar story of puny Europeans not being able to take on bigger, more competitive Americans. At one time, the Pacific and Atlantic fauna were equivalent, explains Roopnarine, but over many millions of years, the rich, upwelling waters of the Pacific have promoted intense competition and the evolution of bigger species. In the Atlantic, by contrast, there has been a series of extinctions. “If you pick any guild of mollusks,” says Roopnarine, “whether they are suspension feeders or grazers, they are larger in the Pacific and competition in the Atlantic will be dominated by these Pacific species.”

  The barrier that holds back this invasion of bigger beasts is not the cold of the Arctic, but its lack of food. Once the ice melts in summer, the seas will receive more sunlight and more plankton will grow in the warmer waters, just as we are beginning to see. The “food barrier” will fall. How long will the invasion take then? “When conditions are right, and once they begin to move, it is a matter of just a few years before they are fairly widespread,” says Roopnarine.

  Does the same argument apply to many other creatures of the Pacific seas? “I think it would be safe to say that other organisms that have not been documented geologically but are ecologically similar are probably going to do the same thing. We have a lot of echinoderms [starfish], coelenterates [jellyfish and anemones], and fish ready to move.” By the 1990s, plankton that were once specific to the Pacific had begun to move to the North Atlantic.4

  The travels of starfish, sea anemones, and plankton may pass unnoticed by all but marine biologists, but fish are a very different matter. We know that fish can move rapidly when waters warm and whether they enter the Arctic from the Pacific or the Atlantic, fishermen and the big industry behind them will take note.

  Two areas of the Arctic and its adjoining waters, the Bering Sea and the Barents Sea, are among the world’s richest fishing areas. Over half the fish harvested in the United States come from the Bering Sea, while more than half the fish eaten in Europe come from its Arctic waters. A lot of people—fisherman, fishery regulators, and pirate fishermen—are watching out for changes in the Arctic’s fish with dollar signs in their eyes.

  Change can come with great speed. I visited a small museum in the town of Ilulissat, which is Greenland’s biggest fishing port. There I was told the strange tale of how a small shift in the temperature of the nearby seas led Greenland’s indigenous folk to dance the foxtrot, and even the tango, a remarkable case of how fish can affect human behavior.

  In the 1920s, a branch of the Gulf Stream, the Irminger Current, changed its pattern of flow and brought warmer than usual water to the west coast. Seals retreated north and Atlantic cod flooded in. All of a sudden, seals, the mainstay of Greenland’s indigenous hunt, were hard to find, but cod were plentiful and easy to catch and sell on the international market. Cod fishing ventures and salting houses sprang up at great speed all over west Greenland.

  That brought cash to the indigenous economy, and glossy mail-order catalogues from Denmark were not far behind. Sealskin boots went out of fashion as Western styles arrived along with new furniture, foods, and—most desirable of all—the gramophone and popular music of the day. Out went the traditional music of song and drum, along with the reels and foot-stomping dance tunes brought to northern communities long ago by Scottish whalers. Young Inuit took to the tango and foxtrot.

  The good times eventually went too far. In the early 1960s, 400,000 tonnes of cod were being caught per year, which was more than the seas could bear. Overfishing and a more gradual temperature change finished off the cod. Shrimp fishing largely replaced it and that is now Ilulissat’s biggest catch.

  The shift in the Irminger Current is a particularly famous example, but it is only one of a great many natural changes in the seas that have sent fish swimming somewhere new. Climate clearly matters. Nevertheless, I was not surprised to hear that an exhaustive study of the future of Arctic fisheries commissioned by the Arctic Council concluded that: “The total effect of climate change on fish stocks is probably going to be of less importance than the effects of fisheries policy and their enforcement.”

  It is easy to see why. Almost everywhere you look, greed and the inability of governments to set and enforce sensible rules are destroying the world’s fish. At the peak, in 1968, factory trawlers from all over the world were taking 800,000 tonnes of cod a year from Newfoundland’s Grand Banks, a fishery so rich that early visitors claimed you could catch cod simply by lowering a basket over the side of the boat.

  By 1992, the Grand Banks’ wealth was utterly exhausted: the fish were gone, the fishery closed, and 30,000 jobs were lost. The cod have never come back. Around the Atlantic, you can name almost any fish you like and then find a date when stocks collapsed owing to overfishing. Take the Norwegian herring, for example: 2.5 million tonnes were taken in 1965 and a total collapse followed in 1972. Capelin fishing replaced herring fishing. That collapsed in the mid-1980s. Almost everywhere too many fishermen chase too few fish, and national governments cannot agree on the right action, or dare not implement the measures that they know are needed.

  On the Pacific side of the Arctic, the fisheries managed by the United States have fared much better. Their part of the Bering Sea has the reputation of being the best-m
anaged fishery in the world, and its catch of walleye pollock is enormous. But take a step west into the “Donut Hole,” an area just outside U.S. waters and east of Russian waters, and we return to the usual tragedy of the commons. At its peak, in 1989, trawlers from Russia, Japan, China, Poland, Korea, Spain, and other nations rushed to its unregulated waters. In 1992, the fishery collapsed. It has not recovered. On the Atlantic side of the Arctic, a similar story can be told of the “Loop Hole.” It is an odd patch of international water, hemmed in on all sides by the 200-mile exclusive economic zones that extend from Russian or Norwegian territory. In the early 1990s, changes in ocean temperatures started bringing large numbers of cod to the Loop Hole.5 Norway and Russia wanted to manage this new fishing ground in a sustainable way, but fishermen from other nations, especially Iceland, had already shown up and were taking all the cod they could. Only after nine years of talks was an agreement reached. By then the Loop Hole had been fished to exhaustion.

  These stories of fishermen and the failure to control them have a special significance for the new Arctic. Commercial fish from southern waters are moving north. There are the Atlantic cod moving up past Svalbard. Over in the Bering Sea, pollock are moving north and bringing with them the salmon that feed on them. Juvenile pink salmon are showing up in the rivers that drain into the Arctic where they have not been seen before. This is the beginning of the new Arctic ecosystem that is forming as the old Arctic dies. If the new Arctic is ravaged by uncontrolled fishing, if invading fish are followed by invading fishermen before a new marine ecosystem can establish itself, we could end up with the worst of all possible worlds, neither a new Arctic nor an old Arctic, but an Arctic desert. There is a sad joke among fishery scientists that the Arctic could end as a “jellyworld” in which only jellyfish, a form of life that needs little energy to sustain it, is left wandering in the open Arctic seas. A more likely end is that only very fast reproducing species like squid and shrimp would survive.