Trouble for walruses in warming world

In the early fall of 2010, over ten thousand walruses were spotted on the Northern coast of Alaska. That many walruses onshore is an unprecedented sight, according to Tony Fischbach, a wildlife biologist for the U.S. Geological Survey.

Tony Fischbach: They normally spend their entire summer in the Chukchi Sea, which is a sea between Alaska and the Russian Far East, and these walruses feed on clams there.

Fischbach attributes their presence onshore to the Arctic’s melting sea ice.

Tony Fischbach: It’s a really different game for walruses. Suddenly they’re stuck onshore. Previously walruses got to the middle of the sea by riding on sea ice flows. In recent years these sea ice flows have melted.

Fischbach tracks the movement of walruses – and ice – using data collected from satellites, direct observation, and electronic devices attached to the walruses themselves. He said melting ice has created special challenges for female walruses trying to feed and nurture their young.

Tony Fischbach: Female walruses spend a lot of time with their calves. Suddenly they’re forced to swim great distances between the shore and these feeding beds. These feeding beds are 150 to 200 miles offshore. They’re no longer hopping off a piece of ice and feeding directly underneath them.

He explained it’s not been affecting the males as heavily, as far as he can tell.

Tony Fischbach: The boys have a lot less to worry about they don’t take care of the calves. They’re different from the females. They have this unique adaptation where they have these inflatable pouches underneath their shoulders which they can fill with air, so they can rest at sea. The females can’t do that.

The females have to rest on something stationary, like ice, or land.

Fischbach also clarified that not all Arctic ice has melted, just the ice in shallow water that’s handy for walruses. In other words, the ice has moved north over colder, deeper water, where walruses have nothing to eat.

Tony Fischbach: We’re just learning where all these clam beds our, it’s a big aspect of our study, and what it “costs” them to commute to from their resting spot on shore to the clam beds.

He explained why he feels walruses are so magnificent, and also difficult to study:

Tony Fischbach: They live in a difficult place to work. They spend 80% of their time in water in a large area. To access walruses you typically need to fly aircraft far offshore over very dangerous waters. We’ve lost people doing this sort of tracking work. So everything we learn about the walruses is a piece of the puzzle.