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“…the Western Arctic Caribou Herd is not the only herd in decline.
Others in Alaska and Western Canada also are thinning.
“Taken collectively, these declines may merely be coincidence,” Dau
said in a written statement. “Alternatively, we may be entering a
phase when conditions throughout North America are less favorable for
caribou than during the past 30 years.”
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Seattle Post-Intelligencer
May 18, 2008
Alaska’s largest caribou herd falls by 20 percent
http://seattlepi.nwsource.com/local/6600ap_wst_alaska_caribou.html
THE ASSOCIATED PRESS
ANCHORAGE, Alaska — Alaska’s largest caribou herd fell by 20 percent
between 2003 and 2007, according the latest count by the state
Department of Fish and Game.
The Western Arctic Caribou Herd declined by 113,000 animals after
years of steady growth.
The reasons are not clear, said Jim Dau, the lead state biologist on
the herd since 1988, but warm spells in the middle of recent winters
may have played a role.
The herd ranges from the North Slope to Eastern Norton Sound and from
the Chukchi Sea to the Koyukuk River. It remains twice the size of
any other caribou herd in Alaska.
The herd is important for subsistence hunters in dozens of villages.
It’s also a major moneymaker for businesses that cater to sport
hunters and a key link in the area’s food chain, Dau said.
The population of the herd fell to as few as 75,000 animals in the
mid-1970s but had recovered to an estimated 490,000 in 2003.
New estimates based on aerial surveys in July 2007 put the number at 377,000.
The decline could be a natural occurrence due to disease, predators
and a shortage of food, Dau said.
“I’m not absolutely sure that that’s what happened here,” he said.
The herd suffered at least one tough winter since the previous census.
In 2005, just before Christmas, temperatures grew unseasonably warm
for four days and it rained for two of those days, Dau said.
After the rain came freezing temperatures, which covered the ground
in a hard crust of snow, and caribou struggled to find food, he said.
In 2007, there was another warm winter spell but extended warm
temperatures and high wind swept away the snow and herd thrived.
Climatologists predict midwinter thaws will become more common, Dau said.
Sue Steinacher, a wildlife education information specialist for the
state, said that when the Western Arctic herd reached nearly half a
million caribou, wildlife watchers wondered how long the herd could
continue to grow.
While the recent decline did not come as a surprise, Steinacher said,
it’s the first big dip in 20 years.
State biologists conduct their population survey with an old U.S.
Geological Survey mapping camera mounted in the belly of a
deHavilland Beaver. The state estimates it caught 99 percent of the
herd on camera.
Last fall, a veterinarian tested tissue and organ samples from the
herd, giving the caribou high marks for overall health, according to
the Department of Fish and Game.
The herd’s death rate was low and calf survival rate was high in
2007, Dau said, but the Western Arctic Caribou Herd is not the only
herd in decline. Others in Alaska and Western Canada also are
thinning.
“Taken collectively, these declines may merely be coincidence,” Dau
said in a written statement. “Alternatively, we may be entering a
phase when conditions throughout North America are less favorable for
caribou than during the past 30 years.”
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