 Puzzle in the Pribilofs
Consortium researchers set sights on northern fur seals
It is early July, and summer has arrived in the northern most reaches
of the Bering Sea. For a few short months each year, winter relaxes its
icy grip and provides local wildlife with a fleeting window for mating
and birthing the young of the year.
On the far-flung Pribilof Islands, an obscure
five-island chain in the eastern Bering Sea, a most unlikely event
is occurring. Hundreds of thousands of northern fur seals (Callorhinus
ursinus), once pushed
to the brink of extinction, have converged on the Pribilofs in time
for the breeding season. More than 57% of the world’s million-strong
population of northern fur seals comes here to breed, providing a spectacular
display of nature’s resilience.
Few species on Earth have faced extinction and lived to tell the tale.
One look at the thick, luxurious coat of a northern
fur seal makes the cause of their historic near-extinction immediately
apparent: they were hunted into obscurity. Beginning in the 1780s and
continuing unabated until 1911, northern fur seals were hunted for
their thick pelts, on land and at sea, with an intensity that reduced
the Pribilofs’ breeding
population from 2.5 million to just 300,000 individuals.
Since the 1911 International North Pacific Fur
Seal Treaty—which
prohibited Japan, Russia, Canada and the United States from killing seals
at sea in the North Pacific—populations of northern fur seals have
recovered from this historic low. But their present population of about
600,000 is a far cry from the 1950s level of 2.1 million, and it continues
to decline at a rate of 6% per year.
The causes of the current decline are unknown and are likely complex. Northern
fur seals spend eight months of the year at sea, scattered throughout the
North Pacific, only coming ashore in summer to mate. Their breeding distribution
and behavior is well studied by scientists, but they remain an enigma for
the rest of the year.
 Reports From the Field
With hunting pressure almost entirely removed, save a small subsistence
hunt on the Pribilof Islands, the ongoing decline of northern fur seal
populations poses a puzzle to researchers. Are commercial fisheries influencing
the availability of their key prey? Could disease or pollution be a factor?
Are killer whales or natural variations in ocean climate affecting them?
Scientists with the North Pacific Universities Marine Mammal Research
Consortium have identified northern fur seals as a key area of interest,
and are currently studying the breeding population in the Pribilofs.
Pamela Lestenkof, a Masters candidate at the University of British Columbia
who hails from the Pribilof Islands, has embarked on an ongoing field
study of northern fur seals. Over the summer, this website will feature
her exclusive updates from the Pribilofs describing her research and
experiences in the field.
Consortium researchers have also prepared a new
section of this website
detailing the natural history and conservation status of northern fur
seals.
Summer is brief in the Bering Sea, and soon the hundreds of thousands
of breeding northern fur seals will abandon the Pribilof Islands for
the sanctuary of the open ocean. If winter is kind to them, they will
return en masse next summer in an attempt to renew and reinvigorate
their dwindling population. And Consortium scientists will be on hand,
carefully studying their biology and ecology in an attempt to conserve
these important denizens of the North Pacific Ocean.
For more information on northern fur seals see:
NEW northern fur seal biology section describing diet, reproduction,
distribution and more. Stay tuned for 'Reports from the field' over
the coming months.
12 July 2006
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