What’s causing a massive walrus haulout in northwest Alaska?
Jill Burke |
Sep 11, 2010
Look to the north from a seaside street in the small village of Point Lay, Alaska and you'll witness a phenomenon that has locals and scientists alike awestruck: A few miles down the coastline, tens of thousands of walruses are jammed together in a tight beach-bound pod to catch a little R&R from their daily routine. This is not a small group -- we're talking in the neighborhood of 40 million collective pounds of massive marine mammal. "You can see them right now," said Leo Ferreira, the village's mayor, late Friday afternoon. "I am on the main road facing the ocean, I am right by the church and I can see them right here and they are about two miles away." Ferreira theorizes that ship traffic is diverting the walruses to shore in unusual increasing numbers. But government scientists suspect it has more to do with an increasing lack of sea ice. Walruses have been known to haul out onto land in large numbers in Russia, but never on the Alaska side of their migratory corridor in the tens of thousands, as is being witnessed this year. Walrus researchers with the United States Geological Survey estimate there could be anywhere from 10,000 to 20,000 of the mammals currently taking a rest along Alaska's Chukchi coastline. Ferreira, one of about 234 people who call Point Lay home, thinks the numbers may be even higher. Since only about 20 percent of walruses generally come to shore, scientists suspect another 80,000 walruses may be swimming nearby. In 2007 and 2009, large number of walruses parked themselves on Alaska beaches in clusters as large as 600 to 800 each. Last year near Icy Cape, a trampling event led to the deaths of more than 100 of the animals, most of whom were juveniles crushed as the group headed for water en masse, likely after getting spooked. By what remains unknown. Steps are being taken to try to make sure that doesn't happen with the group hauled out in Point Lay. Flight restrictions have been imposed, and the village is refusing to indulge out of town tourists who are shopping around for boat rides to get a closer look. Hunters have been asked to stay away from the main group, and people seem to be respecting that request, according to Ferreira. USGS scientists traveled to Point Lay earlier this month to tag some of the walruses in an effort to track and study their movement. They're particularly interested in how much more swimming the hauled out walruses, most of which are females, will have to do to find food and how that extra effort will affect the animals' health. They're also worried about how young walruses -- which rely on a mother's care for two years and which nurse for the first six to seven months of life -- will fare. "We suspect it will have real change in the cost of making a living for the walrus. Instead of rolling off the ice and having your food right there, they might have to commute," said Tony Fischbach, a USGS walrus researcher who just returned from the field trip to Point Lay. Walruses use sea ice to travel a shallow-water food corridor between Russia and Alaska, feeding on clams, worms and other creatures from the sea floor, heading to the ice every day or so for a rest. Scientists don't know what walrus endurance is like in the water without a break, but suspect it tops out at about 10 days. Their dense, heavy body weight -- which can reach two to three tons for mature adults -- makes them relatively inefficient in the water compared to other marine mammals, according to Dan Monson, who is also with the USGS's walrus research project. Males may be more adaptable, thanks to a built-in ability to hang out longer than females in ice-free waters thanks to air-trapping throat patches that help keep them afloat. It allows them to rest with a "big wad of air in their cheeks, but females and calves do not have that ability," Monson explained. |











