Walruses Move Ashore as Sea Ice Melts
March 30, 2012
The beaches of Alaska’s northwest coast are getting crowded. Giant aggregations of walruses are an increasingly common sight on the lands adjacent to the Arctic Sea, where warming temperatures have caused sea-ice—an important walrus habitat—to retreat farther into the Arctic Basin, and largely out of reach.
In both 2010 and 2011, walruses hauled out onto the northwest Alaskan coast in the tens of thousands—a phenomenon previously unknown to the region. Historically, females and their calves have used sea ice to rest, eat, and float to new feeding areas. But with the ice now restricted to areas over deeper waters, walruses avoid it, as they cannot swim to such depths to feed (walruses root out their prey from the ocean floor). Consequently, the animals are increasingly forced to feed in the shallow coastal waters, and swim to land to rest.
On land, walruses face greater risks to their survival. They can exhaust the food supply near the coastal haul-out locations, and their calves are prone to injury or death, as larger walruses often stampede when faced with minor disturbances such as rocks falling from a cliff or seabirds taking off in a flock. A young walrus can easily be crushed in the ensuing chaos. Village dogs may also harass land-bound walrus herds, and industrial activities, particularly those involving planes and helicopters, can also cause problems.
To address these challenges, conservationists from WCS, together with their scientific colleagues, Native groups, and agency staff from both the Russian Federation and United States recently met at a workshop in Anchorage. The experts discussed how to count and monitor walruses in such large aggregations, how to respond when the animals begin using new coastal areas—particularly those close to development activities or villages, and effective protocols to understand disturbance, disease outbreaks, and mortality among the herds.
“To protect the world’s walruses, it is critical that we move quickly in assessing how to respond to this recent phenomenon,” said Dr. Martin Robards, Director of the WCS Berengia Program. “This means planning with our partners both at home and abroad, gathering and sharing consistent data, and understanding the science behind these events. Armed with this knowledge, we can make timely recommendations to wildlife managers and industry that provide the best chance for walruses to safely adapt to their new environment.”
Industrial disturbances are expected to markedly increase over the coming years, as offshore developments are planned in the Chukchi Sea. Of most concern, hauled-out walruses on some Russian beaches can number as high as 100,000, which likely represents about half of the entire walrus population. Under such conditions, localized accidents, such as oil spills, could pose serious danger.
By understanding haul-out use, population demographics, disturbance factors, and sources of mortality, scientists and indigenous partners can better inform land and resource management decisions, impact assessments, mitigation strategies for development projects and tourism, and contingency plans for disaster response.
To learn more about the workshop, read the press release.