Rare gray whale swimming toward Alaska from Russia

TRACK: Western gray surprises scientists by crossing Bering Sea.

January 14, 2011 

A highly endangered whale typically seen near Russia's shore is taking a swim across the Bering Sea toward Alaska.

U.S. and Russian researchers are tracking a 13-year-old male western Pacific gray that has made it more than halfway across the Bering Sea, reaching shallow continental shelf waters, said Bruce Mate, director of Oregon State University's Marine Mammal Institute.

"This animal is probably surprising everybody by having crossed most of the Bering Sea so far in the last two weeks," Mate said.

Scientists can't say the whale is out of place. They don't know where western Pacific gray whales usually are in January.

"That's why we did this," Mate said of the tracking project. "We only really know these animals during their summer feeding season, and they're predominantly around Sahkalin Island at the south end of the Sea of Okhotsk."

Eastern Pacific gray whales, also called California gray whales, are a familiar sight in Alaska waters. They feed in the Bering, Chukchi and Beaufort seas in summer and migrate down the West Coast each winter to breed, mostly in the bays of Baja California. They were taken off the endangered species list in 1994. Their population stands at about 18,000, Mate said.

In contrast, western Pacific gray whales are the second-most threatened species of the large whales, behind North Pacific right whales, Mate said, and their population stands at just 130 animals.

"Almost all of those animals are known on sight from photo catalogs, and most of them have been biopsied for genetic analysis," he said.

Western gray whales were decimated by whaling in previous centuries and feared to be extinct in the mid-1970s. A population was rediscovered off Sakhalin Island, the Russian Island north of Japan, and has been monitored since the mid-1990s.

Sakhalin Island is the site of major offshore oil and gas activities. Whales also face threats from accidental entanglement in fishing gear. Five female western gray whales have died by entanglement over the past four years.

Gray whales are the only baleen whales that are mainly bottom feeders, according to the Alaska Department of Fish and Game. They feed by scraping the side of their head along the ocean floor and scooping up sediment, capturing small invertebrates on baleen and expelling sediment and other particles through the baleen fringes.

Gray whales rarely feed while migrating or during the winters in the tropical waters. Instead, they live off fat reserves built up during summers, when they each eat about 1.3 tons of food per day. A typical male is 45 to 46 feet long.

Mate and others in the research program had hoped to tag a dozen western Pacific gray whales, but two typhoons and two gales interfered.

"We felt pretty lucky when we tagged this animal on the last possible day of our field work," he said.

The whale, dubbed "Flex," was tagged in September with a tracking device the size of a small cigar.

There were hypotheses about where the animals spend their winters.

"One was that it would go down the Asian Coast and perhaps wind up in the southeast China Sea," Mate said. "Another was it might spend time off the Kamchatka Peninsula."

Instead, from about point about where the Aleutian Islands would intersect with Russia's Kamchatka coast, the whale on Jan. 3 began swimming east. By Sunday, it had reached the slope edge of the Bering Sea shelf north of the Aleutians, where waters decrease in depth from about 13,000 feet to about 240. The whale had covered more than 750 miles in 164 hours, for an average of 4.6 mph.

Satellite monitored radio tags have lasted as long as 385 days on a gray whale but average four months. The tag on "Flex" has been attached about 100 days. Mate can't predict how long it will stay attached.

He also doesn't know if Flex has company. Baleen whales generally don't bunch up except when congregating in prime feeding areas.

It's not the first time a gray whale has shown up in a surprising place. Gray whales were hunted to extinction in the Atlantic Ocean in the 18th century, but one showed up last year in the Mediterranean Sea off Israel.

"That was definitely the largest straying observation of any whale species in human knowledge to date," Mate said.

It likely was an eastern Pacific whale that crossed by way of the Northwest Passage. That would have been the shortest route and the one most favorable to its feeding regime, Mate said.

The public can track the rare western Pacific whale at the Oregon State website at http://mmi.oregonstate.edu/Sakhalin2010. It's updated every Monday.

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