Ocean Watch
By Susan Scott
Friday, January 4, 2002
LAST week I wrote that seabirds eat flying fish and flying squid. "Flying squid?" a reader wrote. "Surely these merit their own column. (I know, don't call you Shirley.)" Squirrely squid are known
to take trips upstairs, tooActually, I don't mind being called Shirley because it was my father's name. Anyone with a lick of sense, though, called that cowboy Bud.
But on to flying squid.
A few years ago, I mentioned flying squid in a column, and another reader wrote, "Not to be critical, but didn't you mean flying fish?"
No, there really are flying squid. During an offshore voyage once, we once found a flying squid lying on the 6-foot-high deck of our sailboat. That might not sound like much of a jump, but this squid was only about an inch long. Flying squid have been found on ship decks 12 feet above the water's surface.
The squids that make such leaps belong to the squid family Onycoteuthidae.
Members of this group have long narrow bodies and such powerful funnels they can shoot from the water like little rockets.
Actually, squids don't fly any more than flying fish fly. They glide. Both these creatures burst from the water at speed and then soar on aerodynamic fins.
Squids are the speed demons of marine invertebrates, reaching rates of 24 mph. Such a burst of speed is called escape swimming and usually occurs when a predator is about to eat the squid.
During less stressful moments, squids can hover, cruise slowly and swim in precise directions.
They do all this using their multipurpose mantle, the thick cloak of muscle surrounding squid bodies. For a squid, its mantle is everything. It protects the soft body organs, creates water flow for respiration and is the organ of jet propulsion.
Here's how it works. Between the squid's mantle and its body is a space, or cavity, containing gills. The squid opens the top of its mantle (around the neck) and inhales water into the space. To exhale, the muscular mantle contracts. This closes the top opening and forces water out through a tube called the funnel, located under the head.
The squid can move its funnel, enabling the creature to swim in all directions. Small triangular fins on the outside of the mantle stabilize the squid and fine-tune its course. These fins can also propel the animal slowly.
When the squid needs speed, it contracts its mantle strongly, pushing water out the funnel with great force. Bending the funnel backward causes the squid to dart forward so it can grab prey. But when the funnel points forward and straight, the squid shoots backward like a tiny torpedo.
All squids dart with some speed, but the flying squids are champs. Their superstrong mantles, dartlike bodies and gliding-style fins make them able to clear the water and "fly" away from whatever is chasing them beneath.
Unfortunately, there is often something chasing them from above, too. The seabirds are up there, cruising over the water in constant search of food.
So just when the poor squid escapes the jaws of a tuna by bursting from the water, it gets plucked from the air by an albatross. But that's nature.
Because squid are mostly offshore animals, it is rare to get a look at a live one while snorkeling or diving. But right now, the Waikiki Aquarium has several Hawaiian reef squid on display. This is a rare exhibit that won't last long, because these squid live only about nine or 10 months. They're worth a visit. Surely.
Marine science writer Susan Scott's Ocean Watch column
appears weekly in the Star-Bulletin. Contact her at http://www.susanscott.net.
