Page 113 - MIN VOS 18 feb,2016

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SCIENCEThursday 18 February 2016

Study shows beluga whales dive to great depth to catch cod

DAN JOLING This May 11, 2011 photo released by North Slope Borough and the National Oceanic and Atmo- that formerly had been
Associated Press spheric Administration (NOAA) shows a beluga whale pod in the Chukchi sea near Alaska. covered year-round with
ANCHORAGE, Alaska (AP) sea ice, trying to learn
— Beluga whales off Alas- Associated Press what habitat they use on
ka’s northern coast target their long migrations.
Arctic cod and will dive and a thick blubber layer Alaska has five popula- Hauser and other research- Without much information
to great depths to reach that can be 5 inches thick, tions of beluga whales. ers looked at data collect- about the diet of belugas
them, according to data according to the Alaska Two spend winters in the ed from 30 whales tagged in the Arctic Ocean, Haus-
collected over 15 years Department of Fish and Bering Sea, and when sea over 15 years from 1997 to er and other researchers
that provides insight into Game. ice melts head through the 2012. matched dive information
their foraging patterns in Male belugas grow as long Bering Strait into the Chuk- One retained a tag for 18 to data they had on the lo-
the remote region under- as 15 feet and females to chi or Beaufort seas. months. cation of schools of Arctic
going profound changes 12 feet. They feed on salm- During the study, research- Polar bears and Pacific cod and found a correla-
from climate warming and on, crab, shrimp, squid, ers applied tags linked to walrus need sea ice as a tion.
a loss of sea ice. clams and small schooling satellites to whales. When platform for hunting. Be- The whales likely made
The dive information on fish such as herring, cape- tagged belugas surfaced luga whales can move dives based on where
two U.S. Arctic Ocean be- lin, smelt and cod. They are to breathe, the tags would around it. prey was concentrated by
luga populations showed hunted by Alaska Native transmit locations and dive The researchers tracked oceanographic features
the white whales in the subsistence hunters. depths. belugas into feeding areas such as undersea slopes
Chukchi and Beaufort seas from shallow to deep wa-
diving as deep as 900 me- ter, Hauser said. The whales
ters — or more than 2,950 commonly dove 650 to
feet. 1,000 feet.
The lead author of the “So we could confirm,
study says it adds to the for one thing, that there
limited information scien- was this correspondence
tists have on the diet and between the depths the
behavior of the two whale Chukchi belugas were
populations. diving and the depths at
“In the context of a chang- which Arctic cod were
ing Arctic with changes in most abundant,” she said.
sea ice in particular, but The tags attached to the
also changes in anthro- belugas could record
pogenic interest, it’s sort dives to 1,000 meters, or
of important to get some 3,280 feet.
benchmarks and some One male beluga dove to
baseline information,” said 956 meters, or more than
lead author Donna Hauser, 3,100 feet, in the Cana-
a doctoral student in the da Basin, which reaches
University of Washington’s depths of more than 10,000
School of Aquatic and Fish- feet. Researchers don’t
ery Sciences. know why belugas would
Belugas are small, toothed dive so deep there, Hauser
whales born gray that turn said.
white as they age. They The research was pub-
have muscular bodies lished in the journal Marine
with distinctive, bulbous Ecology Progress Series in
structures on the forehead December.q