Source > http://www.deseretnews.com/dn/view/0,1249,650213839,00.html
Sea lions are disappearing
Scientists studying reasons for animals' rapid drop in Alaska
By Alex de Marban
Anchorage Daily News
ANCHORAGE, Alaska The days of state-sanctioned sea lion hunts are
long gone in Alaska, but fishermen and hunters who gunned down the sea lions
are suspects in the latest study about the animal's crash.
Scientists puzzling over Steller sea lion numbers that plummeted about 75
percent in parts of Alaska in the last three decades have considered such
theories as over fishing, changing climate, diet and killer-whale attacks.
But the consequences of fishermen blasting sea lions to protect fish or
gear, and hunters harvesting thousands of pups for pelts, haven't been
significantly studied, said researcher Henry Huntington.
Yet sea lion shootings took place for decades until 1990, sometimes in
large numbers, and might have played a key role in the collapse, he said.
Fishermen slaughtered sea lions for revenge often aiming for adult
females because they punctured buoys, snatched fish and destroyed nets, said
Clem Tillion, a former state lawmaker and commercial fisherman.
Tillion participated in those killings and in state-authorized hunts in
the 1960s.
"We shot them because we didn't like them," he said. "They'd get on your
gear and take your halibut off. They were underwater and you couldn't hit them
then, so everyone would get real mad and go to a haul-out or rookery and just
butcher sea lions for what they'd done to your gear."
"Everybody shot sea lions. They were a pest, like ranchers consider
coyotes."
The shootings didn't really hurt Steller sea lion numbers when the
population was healthy, Tillion said. But they had a severe impact as soon as
their numbers began dropping sharply.
The barking, barrel-chested creatures, some weighing more than a ton,
lounge on rocks or beaches from Japan to California, occupying many of the same
areas where boats haul in fish.
They are divided into two stocks, at a line just east of Prince William
Sound. The estimated size of the western stock in Alaska, extending out to Attu
Island, peaked at 195,000 in the mid-to-late 1970s.
This stock is now considered in danger of extinction. It began plummeting
in the Aleutian Islands. The decline spread eastward, and the stock nose-dived
at a 15 percent annual clip in the late 1980s.
The losses continued after 1990 but slowed substantially. That year,
shooting became illegal except for Native subsistence hunts because Steller sea
lions were listed as threatened, a step short of endangered.
As the population kept dropping, the western stock in Alaska was declared
endangered in 1997. The stock made small comebacks in recent years and was
estimated at 45,000 sea lions in 2004, including about 20,500 adults.
Shootings are rare today, said Ken Hansen, a longtime federal enforcement
officer in Kodiak.
Why are they declining?
Estimated Steller sea lion numbers in Western and Southcentral Alaska
fell from as high as 195,000 in the late 1970s to about 45,000 today.
Hypotheses about why the animals took a dive include:
Competition for fish with the commercial fishing industry
Climate change altered the abundance or distribution of fish that sea
lions eat
Disease
Pollutants reduced the birth rate or killed sea lions
Predators such as killer whales
Entanglement in commercial fishing nets
Shootings
Source: The National Academies
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