Text 2440, 86 rader
Skriven 2010-10-04 21:58:00 av JIM WELLER (1:123/140)
Ärende: squid vs salmon
=======================
Manny sometimes sends me stuff on the Humboldt squid, so this may be
of interest...

"The short-lived invasion of the salmon snatchers"

by Justine Hunter in Victoria for the Globe and Mail

It sounds like a dodgy premise for a B movie: An invasion of fierce,
cannibalistic predators from the deep.

But there was a very real threat posed by an unprecedented Humboldt
squid migration into northern waters.

The first encountered Humboldt squid north of California was in
Oregon by chance one night off the coast seven years ago.
Researchers saw something odd: Huge numbers of sardines were
churning the dark water. Then they saw what was causing the panic.
"We were watching these five-foot squid coming up out of the depths,
tentacles first, grabbing fish and then disappearing again." For the
scientists on board, it was thrilling to meet a real-life Kraken
mythical monster. At the time, the Humboldt squid were almost
unheard-of in such northern waters.

Since then, Ms. Weitkamp has come to worry about what this shift
might mean for the oceans. "In some ways it's really scary. It's
this huge biomass. They had one test net last year off the mouth
of the Columbia River and they caught 40,000 pounds of squid in a
single tow of the net." Last year saw a population explosion; squid
were washing up on the beaches of Tofino on Vancouver Island. The
tropical cephalopods were turning up in commercial fishing nets in
Alaska.

But this summer there was a record high return of sockeye salmon on
the Fraser River. Now, the mystery deepens: It seems the Humboldt
squid, the locusts of the ocean, have vanished from the Pacific
north of California this year. This year, researchers have been
searching for them in vain.

Her work has been rippling through the research community. Now the
Cohen commission, the Canadian inquiry into the 2009 collapse of the
Sockeye salmon run on the Fraser River, is asking if the squids'
unwelcome presence in northern Pacific waters may have played a
part. Buried beneath the debate over salmon farming, the Cohen
commission has listed the Humboldt squid as a potential marine
predator of the Fraser River sockeye.

Earlier this year, fishery biologist John Field of the National
Oceanic and Atmospheric Administration in Santa Cruz, Calif.,
confirmed for the first time that the Humboldt squid have developed
a taste for salmon, with the discovery of otoliths, the ear bones
of salmon, in their stomachs.

The Humboldt squid, which can grow to two metres in just two years,
are opportunistic feeders: They'll eat each other and have been
found with seabird feathers in their stomachs.

However the Humboldt squid prefer smaller prey than a full-grown
salmon. While they are feeding on juvenile salmon, he believes the
more significant link between the squid and salmon populations may
be ocean conditions.

Warming oceans have allowed the Humboldt to move north, but this
year, temperatures in the Pacific have dropped, with lots of cold,
subarctic water that is probably very high in oxygen, he said.
Better for salmon, less appealing for the squid.

Confirming that link may help salmon researchers better understand
the wild swings in salmon stocks, and the future of what is both a
profitable industry and a reliable food source.

Ms. Weitkamp expects her chance to study the squid isn't over.
"Squid in general are designed to take advantage of temporary
environmental conditions. And these Humboldt squid are the
specialists. I can only imagine they'll be back."


Cheers

YK Jim


... The real monsters aren't hiding under your bed.

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