A white orca sent researchers and a ship's crew scrambling for their cameras after the nearly mythic creature was spotted during a research expedition near Alaska's Aleutian Islands.

"I had heard about this whale, but we had never been able to find it," said Holly Fearnbach, a research biologist with the National Marine Mammal Laboratory in Seattle, who photographed the killer whale.

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The white orca was recently photographed in Alaska's Aleutian Islands ((NOAA))

"It was quite neat to find it," said Fearnbach.

The orca was spotted last month while scientists aboard the Oscar Dyson, a National Oceanic and Atmospheric Administration research ship, were conducting an acoustic survey of pollock.

The whale appeared to be a healthy, adult male about eight metres long and weighing an estimated 4,500 kg.

A white orca was spotted once in the Aleutians years ago but eluded researchers since, even though they had seen many of the more classic black and white whales over the years.

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The white orca is not a true albino given the coloration, say experts. ((NOAA))

Fearnbach said the white whale stood out.

"When you first looked at it, it was very white," she said.

Further observation showed that while the whale's saddle area was white, other parts of its body had a subtle yellowish or brownish colour.

It likely is not a true albino given the coloration, said John Durban, a research biologist at NOAA's Alaska Fisheries Science Center in Seattle, adding that's probably a good thing since true albinos usually don't live long and can have health problems.

Durban said white killer whales have been spotted elsewhere in the area twice before: In 1993 in the northern Bering Sea around St. Lawrence Island and in 2001 near Adak in the central Aleutians. There have also been sightings along the Russian coast.

While Alaska researchers have documented thousands of black and white killer whales in the Bering Sea and the Aleutians during summer surveys, this was something new and exciting, Durban said.

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Scientists aboard the Oscar Dyson, a National Oceanic and Atmospheric Administration research ship, photographed the rare creature. ((NOAA))

"This is the first time we came across a white killer whale," he said.

The white whale was in a family group of 12 spotted on a day when the seas were fairly rough about three kilometres from Kanaga Volcano on Feb. 23.

The ship stayed with the whales for about 30 minutes.

"Everybody actually came out and was taking pictures," Fearnbach said. "It was a neat sighting for everybody."