Ocean
Watch
Friday, March 09, 2007
Squid pro quo:
Giant differs from colossal
While reading and listening to news reports about a big squid that
Patagonian toothfish fishermen caught recently, I remembered why, 20
years ago, I wanted to write this column.
To me, news stories about marine animals usually fell
short. I almost always wanted to know more, and thought other ocean
enthusiasts did, too.
Take this squid. The Associated Press wrote, "Colossal
squid are found in Antarctic waters and are not related to giant squid
found round the coast of New Zealand."
Oh. Earlier, I thought the word colossal meant a
super-size giant squid. But no. Colossal squid is a new common name for
a different species of deep-sea squid.
The New Zealand researchers who chose this name felt
that colossal conveyed both the size and aggressiveness of the animal.
This is "one of the most frightening predators out there," one said.
"It's without parallel in the oceans."
Frightening to whom? I wondered. I thought the giant
was the biggest squid. Is the colossal a new discovery? And what on
earth is a Patagonian toothfish?
Whether the colossal or giant squid is bigger depends
on what you measure and whom you ask.
My invertebrate zoology textbook shows a picture of a
giant squid stranded in Norway in 1954. The creature is 30 feet long,
measured from the top of the body to the tip of its longest tentacle.
According to the caption, this is a small one. The largest stranded
specimen was 60 feet long.
The colossal squid in the news was 39 feet long, but
the New Zealand biologist studying it believes the animal is only
two-thirds grown. Plus, he says, the body of the colossal is massive
compared with that of the giant squid. His conclusion is that the
colossal is the world's largest squid.
But researchers have to be careful here. Estimates of
deep-sea squid sizes were based in the past on the size of sucker marks
found on sperm whale skin. Later, however, biologist discovered that
sucker scars grow with the whale, making the squid-size estimates far
too large.
My take on size is that giant squids are longer but
colossal squids are beefier.
The colossal is also a more formidable predator. This
creature has swiveling hooks at the end of its tentacles, and the
largest mouth (called a beak in this class of animals) of all squid.
Giant squid, it is believed, hang around waiting
passively for a fish to swim within reach. But colossal squid are active
hunters, particularly of Patagonian toothfish. Most of us know these
6-foot-long fish as Chilean sea bass, a species that is being
aggressively overfished.
It doesn't matter how big or tough deep-sea squids are
when it comes to their sperm whale predators. Squid put up a fight, but
these whales are far more powerful and the squids nearly always lose.
Researchers have known about colossal squid since
1925, but this recent landing is the best specimen they have had to
study. Only six others have been found, five in sperm whales' stomachs.
Giant and colossal squids are the sea monsters of old,
but the notion that they sink ships and eat people is fiction. These
squid have no interest in us or our vessels.
And that answers my questions about deep-sea squid. I
hope it answers yours, too.
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