Walruses on a barrier island


In September of 2013 the National Oceanic and Atmospheric Administration observed thousands of walruses hauling out on a barrier island off of Alaska.  On September 12th an estimated 1,500 to 4,000 individuals present and by September 27th there were approximately 10,000.  While similar events have been reported, scientists say it is a recent phenomenon. Walruses generally use floating ice in the Chukchi Sea to rest while feeding at sea but due to recent climate change and melting sea ice, it is more difficult for them—and other species, such as polar bears—to find resting areas.

According to Physics Today sea ice has reached its lowest area measurements since it began being measured in 1979-with a 55% decrease (7.5 million square kilometers to 3.4 million square kilometers). While sea ice has previously been very thick, containing multiple years of accumulation, the current sea ice is much thinner, containing just ice from one season.  The more transparent ice is much quicker to melt (Martin).

The effects on the individual walruses is varied and widespread.  They will be exposed to more stress, depleted food levels, more energy will need to be expended to find prey, trampling caused by stampedes of spooked walruses and increased predation (Knowles).  Disease also spreads much faster in populations that are overcrowded. There is evidence that certain mollusks, crabs and fish are moving northward and the shift in the food base is of a negative consequence for bottom feeders such as walrus and seal that prey on these species (Martin).  The walrus is currently listed as a “Threatened” species and the increase of stressors they face may push it over the edge to “Endangered.”

Thank You to OCEAN Researcher Nicole Smith

For more information regarding the 2013 haul out, as well as previous ones visit NOAA at http://alaskafisheries.noaa.gov/newsreleases/2013/walrushaulout093013.htm.

Martin, Jeffries, et al. "The Arctic shifts to a new normal." Physics Today. American Institute of Physics. Web. 21 Jan 2014.