JUNEAU -- Alaska's largest caribou herd, the Western Arctic
Caribou Herd, has grown to at least 490,000 animals, according
to a census completed this week by the Alaska Department
of Fish and Game.
This vast herd ranges more than a 140,000-square-mile area
bounded by the Arctic Ocean, the lower Yukon River and the
trans-Alaska oil pipeline. About 40 communities and 13,000
people are located within the range of the herd. For the
indigenous people of these communities, the herd is both
a vital link to their cultural heritage and a staple of their
diet. There is also growing use of the Western Arctic Caribou
Herd by resident and nonresident hunters living outside the
herd's range. These caribou are an important source of income
for commercial operators that provide services to hunters.
Because of its tremendous size, the ecological importance
of the Western Arctic Herd to Northwestern Alaska is incalculable.
Although they are important prey for wolves and bears, these
caribou directly and indirectly impact the entire food web.
Wildlife biologist Jim Dau, Alaska Fish and Game's lead
biologist for the Western Arctic Caribou Herd since the late
1980s, estimates the herd has grown about 1 percent annually
for the last 10 years. That's significant for this herd,
which crashed in the mid-1970s from about 242,000 to 75,000
Counting almost half-a-million caribou is no easy task.
Radio-collared caribou and low-altitude photography are two
The census was staged out of a remote airstrip on the western
North Slope last July. A team of 13 biologists and four planes
were involved, including a Beaver fitted with a large format
U.S. Geologic Survey mapping camera. One or more planes tracked
the herd daily to determine whether conditions were right
for the photography.
"The sample of radio-collared caribou tells us two
things," Dau said. "They obviously lead us to the
groups, but they also indicate what proportion of the herd
percent of a herd this size looks like all the caribou
in the world are beneath the plane. But until we are
certain at least 90 percent of all the collared caribou
are present, we know we need to keep looking for other
During the census the department determined 97 percent of
all collared caribou were present in the various aggregations
The Beaver then flew transects over each group and shot
photographs at a regular interval so that each photograph
overlapped on all four sides.
While the Beaver photographed large groups of caribou, two
Piper Cubs and a Cessna 185 radio-tracked caribou and searched
for small groups that did not contain a radio-collared animal.
When a group was found, the Beaver was either called in to
photograph it or the animals were counted directly from the
Once back in town the photos were laid out and areas of
overlap marked so that no caribou were double-counted.
"It took 11 of us three days to put the overlap lines
on photos," Dau said.
With the overlap lines marked, the tedious task of counting
began. The department took more than 1,100 9-inch-by-9-inch
photographs to capture the herd on film.
Since the Western Arctic Caribou Herd crashed in the mid-'70s,
biologists and hunters have been concerned that the herd
could experience a similar drop in coming years. According
to Dau, Western Arctic caribou have generally been in good
body condition during fall. Following several recent mild
winters caribou were in relatively good condition even during
"The body condition of caribou is really the ultimate
expression of their habitat in terms of quantity, quality
and availability of their food," Dau said.