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Gray whale baby boom holding strong despite persistent sea ice in 2012

Alex DeMarban
Gray Whale breaching. Gray Whales are distinguished from Humpbacks by their lack of a dorsal fin, among other characteristics. Merrill Gosho / NOAA photo

It's apparently a good year to be a gray whale, despite menacing killer whales and the persistent sea ice around much of Alaska that made feeding difficult last summer at the northern extent of their migration.

Biologists this year estimate that a bumper crop of more than 1,100 gray whale calves passed a spot near San Simeon in central California, on their migration from warm lagoons in Mexico, to summer off Alaska's northwestern coast.

Many of the once-endangered whales made it to their feeding grounds in the Far North, from the Bering Sea to the U.S. Arctic Ocean. But some probably got snatched by killer whales along the way.

Wayne Perryman, with NOAA’s Southwest Fisheries Science Center near San Diego, said biologists choose a spot for counting migrating gray whales near San Simeon called Piedras Blancas because the whales often skirt the shoreline there.

The thinking is whales are seeking safety from the orcas, by using the shallower water to confound the killer whales' hunting technique of attacking from below. The noise of the surf might also help the gray whales hide, said Perryman.

But killer whales -- they "make tyrannosaurus rex look like a pussy cat" -- are a problem for gray whales all the way to Alaska. Biologists thought the danger stopped at Unimak Pass, an Aleutian Islands choke point where gray whales slipping into the Bering Sea are vulnerable to attacks from orcas.

"But we now know they track them all way to the Bering Strait," said Perryman.

According to KPBS.org, 1,166 gray whale calves were born in 2012. But the lowest birth rate ever recorded came in 2010, with 254 births.

The gray whales leave in October for Mexico, as do a lot of Alaskans.

Contact Alex DeMarban at alex(at)alaskadispatch.com