Endangered blue whales resurfacing in Alaska

ANCHORAGE — Blue whales are returning to Alaska and could be re-establishing an old migration route several decades after they were nearly wiped out by commercial whalers, scientists say.

The endangered whales, possibly the largest animals ever to live on Earth, have yet to recover from the worldwide slaughter that eliminated 99 percent of their number, according to the American Cetacean Society. The hunting peaked in 1931 with more than 29,000 animals killed in one season.

The animals used to cruise from Mexico and Southern California to Alaska but had mostly vanished from Alaskan waters.

But several sightings in recent years off the coasts of Alaska and British Columbia suggest the massive animals are expanding north again in search of tiny shrimplike krill to eat, scientists contend in an article in the journal Marine Mammal Science.

Blue whales can grow up to 100 feet long and typically eat 4 tons of krill a day during the summer.

Researchers got an inkling of the trend in 2004 during a humpback-whale survey in the Gulf of Alaska, said Jay Barlow, a scientist with the National Oceanic and Atmospheric Administration (NOAA).

After the 2004 sightings, John Calambokidis, a research biologist at Cascadia Research Collective in Olympia, who works with NOAA and the Canadian Department of Fisheries and Oceans, said one or two blue whales were seen each year off British Columbia in 2005 and 2006.

In 2007, researchers saw five in one day near the Queen Charlotte Islands off British Columbia. Three were seen the next day.

Researchers eventually documented 15 blue whales off the coast of British Columbia and in the Gulf of Alaska.

Calambokidis said it appears blue whales are going farther north.

"We speculate that this represents the re-establishment of a traditional migration pattern for an eastern North Pacific blue whale population," the scientists say in the article written by Calambokidis, Barlow and others.