September 30, 2013 at 7:55 pm #441MikeKeymaster
By Jeffrey Hope
Updated: 2:36 a.m. ET April 06, 2004
April 5 – Alaska’s dramatic sea otter population decline has
researchers around the globe concerned. This week, the Alaska SeaLife
Center in Seward is hosting a workshop on the issue. The sea otter
population in Southwest Alaska has been declining for years, and
researchers hope this special conference will help find out why.
It’s a rare gathering of both Russian and U.S. sea otter experts.
Researchers from both countries have been extensively studying sea
otters for years. The last 20 years, there’s been a dramatic decrease
in the sea otter population, from 56 percent to 68 percent down on
the Alaska Peninsula and Aleutian Chain. The cause remains unclear.
Doug Burn is a biologist with the U.S. Fish and Wildlife
Service. “I’d like to see more of these comprehensive studies that
look at things like survival, look at things like starvation, and
what’s out there for them to eat, look at things like contaminants
and disease,” he says. “Basically, this holistic approach to try to
rule out some of these other possibilities and hopefully narrow in on
some sort of cause.”
Burn may get his wish. The conference is designed to help researchers
determine which project should be done next, while the U.S. Fish and
Wildlife Service goes through the long process of proposing the sea
otter be listed as a threatened species.
So what’s to blame? Jim Estes has the most controversial idea so far.
He believes killer whales are eating more sea otters because other
prey populations have also declined.
“It seems to me that the most obvious explanation is that, when they
ran out of these other things, they expanded their diet to include
other species, and sea otters were one of those other species. And
that’s what happened,” Estes said.
Another mystery is that populations in Russia, just a few hundred
miles from Alaska, are stable. The Russians are proposing more
studies in the Commander Islands, an ecosystem the SeaLife Center is
also targeting as an important research area.
“I think we have to give all of the ideas equal weighting until
there’s enough evidence to be able to dismiss them,” said Shannon
Atkinson of the Alaska SeaLife Center.
Over a century ago, some populations were hunted to near extinction.
Now, this population could see a similar fate, but nobody knows why.
The U.S. Fish and Wildlife Service is accepting public comments on
the proposal until June 10. They expect to make a decision by
Researchers say they see almost no sea otter carcasses on beaches
anymore, where they used to be common. That leads them to suspect
that many more otters are dying at sea.
Also, during about 4,000 hours of observation time, biologists saw
killer whales make six successful strikes on sea otters. Researchers
say that, plugging those numbers into a computer model would yield
approximately the decline in numbers that they’re seeing, so it’s
possible that orcas actually are taking thousands of otters each year.
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