The astonishing photograph above could become the new symbol of global warming, showing what happens when walruses lose the sea ice on which they traditionally rest. The image, taken by Corey Accardo during the National Oceanic and Atmospheric Administration's annual arctic mammal aerial survey, shows an estimated 35,000 walruses crowded onto a beach eight kilometers north of Point Lay, Alaska.
Although walruses (Odobenus rosmarus) often collect in large numbers on sea ice, this is the largest gathering seen on dry land. Numbers have fluctuated since the “haul out” was spotted on September 13, peaking two weeks later. Until 2007, walrus colonies on dry land were rare, but in six of the last eight years they have been occurring on a large scale.
Even in less large gatherings, smaller walruses can be injured or killed in a stampede, such as when the group is charged by a polar bear. With a group such as this one, a stampede could have utterly disastrous consequences. Consequently, the US Federal Aviation Authority has ordered the rerouting of flights that could spook the mighty pinnipeds into a race for the water. Aerial film crews have been ordered to keep their distance.
However, while flight restrictions might minimize the risk of baby walruses getting crushed in a frenzy, the major threat to Odobenus rosmarus is climate change. The decline in Arctic sea ice has become so drastic that US Geological Survey's Chadwick Jay warned, “Those animals have essentially run out of offshore sea ice, and have no other choice but to come ashore.”
US Geological Survey. Walruses have become so numerous at some spots they are spilling off the beach.
A USGS statement notes, “Hauling out on shore forces walruses to either forage near shore where their prey base is understood to be of lesser quality or to travel long distances to their preferred offshore foraging grounds.”
While sea ice across the Arctic has been higher this summer than in a handful of previous years, the trend is strongly down with the Alaskan area particularly warm this year.
Walruses play a unique role in the Arctic ecosystem. While hunting for clams and other bivalves on the ocean floor, they release nutrients into the water column and encourage the growth of many species.
The loss of sea ice does not pose the sort of direct threat to humans through drowning of low lying areas that melting glaciers do, but it is thought to be causing unpleasant weather effects in Europe and North America. As World Wide Fund for Nature put it, “We are the walrus.”
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