[MCN] Baby Beluga? Rare, & "hard animals to research"

[Lance Olsen]

Rare beluga data show whales dive to maximize meals
UNIVERSITY OF WASHINGTON
PUBLIC RELEASE: 12-FEB-2016

-----------------------------------Excerpts---------------------------------
"They found the whales most frequently dove to 
depths where Arctic cod congregate (200-300 
meters or 650-1,000 feet), confirming these fish 
are a significant source of food for belugas, and 
that the whales will dive to depths that maximize 
their encounters with prey."

"Both beluga populations frequently dove to the 
bottom of the sea to feed on bottom-dwelling 
organisms in the northern Bering Sea and Chukchi 
Sea, but then dove in more mid-depth ranges along 
areas that sloped from shallow to deep. They were 
likely looking for opportunities to eat based on 
where prey was concentrated by oceanographic 
features, Hauser said."
-----------------------------------------------

Children's singer and songwriter Raffi may have 
brought beluga whales into popular culture with 
his 1980 song "Baby Beluga," but surprisingly 
little is actually known about the life and 
ecology of these elusive marine mammals that live 
in some of the world's most remote, frigid waters.

Two distinct populations spend winters in the 
Bering Sea, then move north as sea ice melts and 
open water allows them passage into the Beaufort 
and Chukchi seas. There they feast on Arctic cod, 
frequently diving to depths of 200 to 300 meters 
-- and sometimes over 900 meters (0.5 miles) -- 
to find food.

As the Arctic continues to change due to rising 
temperatures, melting sea ice and human interest 
in developing oil and shipping routes, it's 
important to understand belugas' baseline 
behavior, argue the authors of a new paper 
published this winter in the journal Marine 
Ecology Progress Series. Its authors drew upon a 
rare dataset that spans 15 years of dive 
information for 30 whales to produce a 
comprehensive analysis of beluga migration and 
feeding patterns in the Arctic.

"This study gives us a benchmark of the 
distribution and foraging patterns for these two 
beluga populations," said lead author Donna 
Hauser, a doctoral student in the University of 
Washington's School of Aquatic and Fishery 
Sciences. "However, there still needs to be 
additional work to see how beluga behavior has 
changed in concert with changing sea ice 
conditions in the Arctic."

Beginning in 1993, researchers worked with Alaska 
Native communities in Northwest Alaska and 
Aboriginal tribes in Canada to tag beluga whales. 
The whales often swim close to shore during early 
summer, making it possible to capture a whale and 
attach a satellite-linked tag to the dorsal ridge 
along its back.

The tags are designed to turn on when the whale 
surfaces to breathe, then transmit locations and 
dive depth to a satellite that then relays data 
back to researchers electronically. Tag 
technology has improved over time, with one tag 
remaining on a whale and transmitting data for 18 
months.

"It's a really fantastic system for getting 
relatively high-resolution information for these 
animals that spend most of their time underwater 
and offshore," Hauser said. "In addition to their 
inaccessibility, these populations use remote 
areas of the Arctic, so they are generally hard 
animals to research."

For this study, the researchers also looked at 
the distribution of Arctic cod, a primary food 
source for both beluga populations, and compared 
that data to the locations and depths where the 
whales dove. They found the whales most 
frequently dove to depths where Arctic cod 
congregate (200-300 meters or 650-1,000 feet), 
confirming these fish are a significant source of 
food for belugas, and that the whales will dive 
to depths that maximize their encounters with 
prey.

The data evidenced this second finding by 
recording diving behavior that was all over the 
map, literally. Both beluga populations 
frequently dove to the bottom of the sea to feed 
on bottom-dwelling organisms in the northern 
Bering Sea and Chukchi Sea, but then dove in more 
mid-depth ranges along areas that sloped from 
shallow to deep. They were likely looking for 
opportunities to eat based on where prey was 
concentrated by oceanographic features, Hauser 
said.

Ultimately, this study helps illuminate aspects 
of a yearly migration that spans thousands of 
kilometers in a region that's experiencing rapid 
change.

"The results of this work can be used not only to 
understand ecological relationships for Arctic 
top predators but also inform the management of 
beluga whales, which are an important subsistence 
resource for northern communities," said 
co-author Kristin Laidre, a UW assistant 
professor of aquatic and fishery sciences.

The researchers will look next at how the timing 
of beluga fall migration south may be affected by 
later sea ice freeze-up in the northern Arctic 
under climate change.

###
Other co-authors are Sandra Parker-Stetter of UW 
aquatic and fishery sciences and the Northwest 
Fisheries Science Center; John Horne of UW 
aquatic and fishery sciences; Robert Suydam of 
Alaska's North Slope Borough Department of 
Wildlife Management; and Pierre Richard of 
Fisheries and Oceans Canada's Freshwater 
Institute.

Beluga tagging was funded and supported by a 
number of organizations, including the Alaska 
Beluga Whale Committee, village of Point Lay, 
North Slope Borough and National Marine Fisheries 
Service (see the paper for a full list).

Funding for Hauser's analysis came from the 
National Science Foundation through UW's 
Integrative Graduate Education and Research 
Traineeship (IGERT) Program on Ocean Change.
-- 
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"Our results indicate that future reductions in 
Arctic sea ice cover could significantly reduce 
available water in the American west...."

Jacob O. Sewall and Lisa Cirbus Sloan. 
Disappearing Arctic sea ice reduces available 
water in the American west
GEOPHYSICAL RESEARCH LETTERS VOL. 31, 2004

*******************************************************
" Š the proportion of the land surface in extreme 
drought is predicted to increase from 1% for the 
present day to 30% by the end of the twenty-first 
century." 

Eleanor J. Burke et al. Modeling the Recent 
Evolution of Global Drought and Projections for 
the Twenty-First Century with the Hadley Centre 
Climate Model. JOURNAL OF HYDROMETEOROLOGY 
OCTOBER 2006

******************************************************
"Linkages between northern high-latitude climate 
and precipitation in the Sierra Nevada suggested 
here could indicate that, under conditions of 
continued global warming, this drought-prone 
region may experience a reduction in 
Pacific-sourced moisture."

Jessica L. Oster et al. Late Pleistocene 
California droughts during deglaciation and 
Arctic warming. Earth and Planetary Science 
Letters 2009
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