Autumn sea north of Barrow heavy with whales

October 2, 2010 

Attracted by some of the smallest creatures in Alaska, dozens of the state's largest gathered recently off Point Barrow.

Bowhead whales in groups of almost 100 were grouped a few tens of miles from Barrow to take advantage of one of the richest whale feeding hot spots off the coast of Alaska. Steve Okkonen was there to see them in the shallow waters above the continental shelf north of Barrow.

"The whales we saw Friday and Saturday were in eight meters of water," said Okkonen, a research associate professor with the University of Alaska Fairbanks School of Fisheries and Ocean Sciences. "That's an eight-meter (-long) animal in eight meters of water, sometimes up to a 15-meter animal in eight meters of water."

The creatures, weighing more than 100 bull moose, were congregating off Point Barrow because of a staggering concentration of one of their favorite foods, krill. Krill, shrimplike organisms about an inch long, are so small it would take a few hundred to fill a cereal bowl. Okkonen and researchers from Woods Hole Oceanographic Institution, the University of Rhode Island, the North Slope Borough and others are studying the Barrow whale-feeding hot spot to determine how unique and important it is, a question developers will be forced to ponder when considering which areas to alter in the search for oil and gas.

From the Annika Marie, a 43-foot research ship, Okkonen and his colleagues witnessed a phenomenon common offshore of Barrow in the fall. Strong east winds help create a current that forces krill toward the shallow continental shelf from the depths of the Beaufort Sea. These east winds also push the krill-infested waters westward along the Beaufort coast toward Point Barrow.

When the east winds settle down, another current flowing northeastward up the Chukchi Sea coast acts as a wall.

"The krill will tend to stack up," Okkonen said.

Sometimes swimming in an echelon formation reminiscent of migrating geese, bowhead whales plow through the stacks of krill, filling their bathtub-size bellies with tens of thousands.

Okkonen and his coworkers want to find out how the Barrow hot spot compares to other great feeding areas along the whales' annual migratory path through cold northern waters.

Bowheads spend their entire lives in the Bering, Chukchi and Beaufort seas.

"In Alaska (the Point Barrow area) is the hot spot, but how important is that spot?" Okkonen asked, adding that areas off Camp Simpson and Kaktovik are also productive for whales.

"We also want to find out if krill overwinter (off Point Barrow after the sea ice forms)."

Point Barrow is an important place for bowhead whales, which pass it during spring as they move from the northern Bering Sea to where they spend their summers in the Canadian arctic. Barrow-area Natives have harvested bowheads in both spring and fall for thousands of years.

Researchers including Okkonen wrote a paper detailing the Barrow hot spot and the prevalence of bowheads in the June 2010 issue of Arctic.

Here is their conclusion: "Because ... whales appear to persist despite ongoing climate variability, the fall whale harvest by the Inupiat community at Barrow should be relatively resilient to climate change. The whale harvest at Barrow could, however, be particularly vulnerable to anthropogenic activities such as ship traffic, oil development or an oil spill."


Ned Rozell is a science writer at the Geophysical Institute, University of Alaska Fairbanks. He can be reached by e-mail at nrozell@gi.alaska.edu.

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