Walrus: Arctic Mammals Very Threatened By Global Warming
Everyone should check out Arctic Tale, it half features the Walrus, half features the Polar bear. forumer.com/viewtopic.php?t=559&highlight=walrus" target="_blank">http://mscao.8.forumer.com/viewtopic.php?t=559&highlight=walrus Here's their Wiki page: http://en.wikipedia.org/wiki/Walrus And an update: http://www.defenders.org/newsroom/defenders_magazine/summer_2008/walrus_in_a_warming_world.php Defenders Magazine Summer 2008 Walrus in a Warming World The melting of Arctic sea ice poses new challenges for Pacific walrus by Bill Sherwonit © Tom & Pat Leeson The first hints that something was amiss in the oceanic world of Pacific walrus washed onto eastern Siberian shores in the late 1990s. For the first time in memory, local residents and scientists saw thousands of walrus cows and calves on land in late summer. Normally the animals are far offshore during this season, floating on the sea-ice pack as it retreats north through the Chukchi Sea, between Alaska and Russia. More disturbing signs surfaced in 2004. A team of climate change researchers cruising through the Beaufort Sea observed walrus calves swimming alone in deep water, far from either ice or land. "Crying" loudly, the calves apparently had been separated from—and possibly abandoned by—their mothers. Alarmed by the encounters, the researchers published their discovery in a scientific journal, noting that nothing like this had ever been reported. Then, in 2007, came two more pieces of bad news. First, scientists reported that the Arctic's summertime ice pack had shrunk to 1.65 million square miles, the smallest expanse since satellite measurements began in 1979. The pack ice vanished completely from the Chukchi Sea, normally an icy refugia for adult females and their calves. Second, female walruses and their young were congregating on Russian and Alaskan shores in record numbers. At least 10 major walrus haulouts were identified in Russia. The largest, at Cape Shmidt, contained an estimated 40,000 to 50,000 walruses in mid-September. Russian researcher Anatoly Kochnev figures that 3,000 to 4,000 walruses died in stampedes at these haulouts last summer, after being disturbed by photographers, hunters, tourists and other people drawn by the unprecedented gatherings. Most of the dead were young calves. Defending Wildlife from Global Warming The plight of walrus, polar bears and other creatures in the Arctic has helped draw attention to the impacts of global warming on the natural world. Defenders of Wildlife is spearheading efforts to urge our nation's leaders to protect our wildlife legacy for generations to come. The solution has two parts. First, we need to address the underlying causes of global warming by reducing greenhouse gas emissions. Second, we must provide the national policy direction and significant new resources necessary to help wildlife survive the global warming impacts already set in motion. Last year, Defenders worked with congressional leaders to introduce legislation—the Global Warming Wildlife Survival Act—that calls for a coordinated, national approach to help wildlife navigate the challenges posed by a warming planet. The core principles of this bill were incorporated into the Senate's major climate-change legislation, the Lieberman-Warner Climate Security Act. While the Senate failed to pass this bill in June, for the first time a majority of senators supported climate-change legislation. Find out more about this legislation and what you can do to help wildlife survive the threat of global warming. The Alaskan haulouts were much smaller, and no deadly stampedes were observed, but the number of walruses that gathered on the state's Arctic coast was historic nonetheless. Walrus experts say several thousand walruses were seen between Point Hope and Barrow, a 300-mile-long stretch of shoreline. "This is a new phenomenon for Alaska," says Chad Jay, a researcher with the U.S. Geological Survey. "To our knowledge, no one has ever observed anything like this before." Jay and other scientists agree that the summer disappearance of sea ice and subsequent migration of walruses to land is a serious conservation concern. Inupiat Eskimos who reside along Alaska's northwest coast wholeheartedly agree. "For centuries we've depended on marine mammals, including walrus," says Vera Metcalf, executive director of the Eskimo Walrus Commission. "Anything that threatens their health and habitat concerns us. Many of us are worried about the receding sea ice and what that means. We're paying close attention to what is happening." So, too, are many conservation groups, including Defenders of Wildlife. "Walruses—like polar bears and other Arctic marine mammal species—are in trouble," says Karla Dutton, director of Defenders' Alaska office. "Global warming is changing their world faster than they can adapt. We need to manage Arctic wildlife in a comprehensive manner or else we risk losing one or more marine mammal species to climate change." In February, the Center for Biological Diversity petitioned the U.S. Fish and Wildlife Service to list Pacific walruses as threatened under the Endangered Species Act. This action puts added pressure on researchers who are now working on the first census of Pacific walrus since 1990. (Another, much smaller walrus population ranges across the North Atlantic; this Atlantic walrus subspecies is estimated to number fewer than 20,000 animals.) Back then, scientists estimated 200,000 to 250,000 walrus inhabited the Bering and Chukchi seas. But the count method was so unreliable that federal managers admit the size of the walrus population was—and has remained—essentially unknown. So no one really knows how walrus numbers have changed, if at all, during this recent period of extreme ice retreat. Using advanced aerial-survey techniques, complicated statistical analyses and a rigorous peer-review of its work, a team of U.S. and Russian researchers expects to have a much more exact count of the Pacific walrus population by the end of 2008. Though it's still too early to predict what impact the shrinking ice pack will have on Odobenus rosmarus divergens, one point is certain: the lives of Pacific walruses are intimately tied to the seasonal movements of sea ice through the Chukchi and Bering seas. The continued summer disappearance of that ice will, at the least, require major adjustments in their lives. Among the largest of the pinnipeds—a group of carnivorous marine mammals including seals and seal lions that propel themselves in the water and (less capably) on land with fin-like flippers—walruses are bottom feeders that gorge themselves on sea cucumbers, crabs, worms and, above all, clams. Using hind flippers to push themselves along, they scour the sea floor with their muzzles, depending on hundreds of sensitive "vibrissae," or whisker-like bristles, to locate food. The largest males, which weigh as much as two tons, can consume 200 pounds or more of succulent seafood in a day. Females, which generally weigh under a ton, eat less, but must also hunt for their calves. The most distinctive of the animal's features are its two- to three-foot-long tusks, which people once believed the walruses used to "dig" for food. In fact, males employ their tusks in displays and tussles over dominance, while both genders use tusks to dig holes in the ice and to help haul themselves onto and sometimes around ice or land. The genus name Odobenus literally means "tooth walker." Though capable of diving down to 200 meters—about 630 feet—when hunting, walruses generally prefer to feed in waters that are 300 feet or less in depth. Unlike other pinnipeds, they need to rest between feeding forays; thus their dependence on ice or land. This also explains the strong link of walruses to the Chukchi and Bering seas, where for ages they have hunted in shallow continental-shelf waters and then rested, bred and cared for young on sea-ice platforms that move south and north across the seas with the changing of the seasons. The life cycle of Pacific walruses begins in deepest winter. Males and females come together in large groups and mate atop the ice-covered Bering Sea. They gather in places where the ice is relatively thin and often heavily fractured, with open-water leads that give them access to sea-bottom feeding grounds. Pregnancy lasts 15 months, with a single calf born in late April or May. Most offspring remain with their mothers for two to three years. Winter's extensive ice cap begins to break up in March. As the ice begins its retreat, most mature males remain in the Bering Sea region, eventually forming large "bachelor haulouts" at several places in and around Bristol Bay. Cows and calves, meanwhile, move north with the retreating ice pack. Doing that affords them several advantages, says Chad Jay: "For one thing, it eliminates competition with the males for food, while increasing access to food resources that are spread across the continental shelf. It also means less disturbance from humans and other predators"—notably killer whales and polar bears. For as long as anyone can remember—and likely for many centuries before that—the southern edge of the ice pack didn't retreat beyond the continental shelf. The slowly moving ice front served as a safe and secure platform from which walrus cows could dive a few hundred feet to the bottom of the Chukchi Sea and retrieve food. It was an ideal situation for raising young. In recent summers, however, the sea ice has retreated much farther north, leaving its southern edges over waters that are thousands of feet deep, beyond the diving abilities of walruses. To find food, cows have had to abandon the ice pack—and in some cases, it appears, their calves. Eventually these animals head for land. Thus the build-up of haulouts, first along the Russian coast and now in Alaska. The large number of walruses at haulouts along Alaska's northwest shores took researchers by surprise. Shell Oil happened to be conducting marine mammal aerial surveys along the northwest Alaska coast in 2007, as a prelude to proposed oil and gas exploration in the Chukchi Sea. By mid-August, pilots had reported numerous walrus sightings, including one large group at Point Lisburne, where a steep, 1,500-foot-high rocky headline overlooks a sand-and-gravel beach. The pilots eventually found the animals spread along the coast from Point Hope to Barrow. Some gathered on the mainland, others chose the network of barrier islands that parallel the shore. Some significant haulouts occurred near the communities of Barrow, Point Lay and Wainwright. Inupiat Eskimo residents of all three villages hunt walrus, but their traditional harvest season is early summer. In 2007, there were no reports of locals hunting the late-summer haulouts, says Joel Garlich-Miller of the U.S. Fish and Wildlife Service. Nor were there reports of other disturbances or stampedes, as occurred in Russia. Although Alaskan walruses apparently escaped onshore disasters last summer, the forced migration from sea ice to shore still poses many threats. When concentrated along the coast, the animals have much-reduced access to the clams and other sea-bottom food they prefer—and what food is readily accessible is likely to be depleted quicker. On land, they're also more likely to be disturbed and possibly hunted, whether by humans or polar bears. Increased disturbances, in turn, will likely lead to more stampedes and increased mortality from trampling, especially among calves. The long swim from ice to shore may also weaken walruses, particularly calves. Anatoly Kochnev notes that "many emaciated and weak animals" were observed at several Russian haulouts. Another big concern: the disappearance of ice from northern waters is likely to prove a boon for energy companies intent on drilling for oil and gas off the coast of Alaska. A Chukchi Sea oil- and gas-lease sale offered by the Minerals Management Service in February drew record-high bids. Led by Shell Oil and ConocoPhillips, seven companies submitted winning bids that totaled nearly $2.7 billion. An alliance of environmental and Alaska native groups pro-*test*-('")ed the sale and several, including Defenders, have sued the federal government for issuing a flawed environmental review, in light of the shrinking ice pack and the uncertain future of sea-ice dependent species such as walruses, polar bears and ringed seals. Besides oil and gas exploration, the retreating ice pack is certain to increase ship traffic through Arctic waters and may eventually prompt the expansion of commercial fisheries into the Chukchi Sea. All of these potential threats must be considered when the government determines whether walrus should be protected by the Endangered Species Act and afterwards, if walrus are listed as threatened. Years may pass before the government decides whether to list Pacific walrus as threatened. But it's already clear that, "given the drastic reduction that we're seeing in the walruses' traditional range, we'll have to be vigilant" to ensure their protection, says Garlich-Miller. The Fish and Wildlife Service, he adds, will work with native Alaskans, industry and Russian researchers to monitor changes in walrus habitat and behavior, lessen industrial impacts and formulate new conservation plans. Will that be enough to keep the walrus population from crashing? As Suzann Speckman, project manager of the joint U.S.-Russia walrus survey, notes, "It's unsettling to realize how little we know about walrus and how fast things are changing." Read Defenders' Navigating the Arctic Meltdown chapter on walruses. Learn more about what you can do to stop global warming. Anchorage nature writer Bill Sherwonit is the author of 11 books about Alaska. His most recent is Living with Wildness: An Alaskan Odyssey, published in 2008 by the University of Alaska Press.