Humboldt Squid Off the Coast of California

From the LATimes:

...It shows up briefly off California every four or five years, spurred by a warm current or some other anomaly, providing a boon for sportfishing businesses.

But amid this latest influx, to points as far north as Bodega Bay, there is a deepening concern among scientists that Humboldt squid are entrenching themselves off California, and may expand northward, eating their way through fisheries as they go. The same thing is happening in the Southern Hemisphere, where squid are being blamed for depleting the hake fishery off Chile.

The first verified capture off Alaska occurred three years ago. A year later, mass strandings made news in British Columbia, where wolves on outer island beaches were seen gnawing on rubbery squid carcasses.

Strandings and the subsequent deaths of squid, such as those along Orange County beaches in March 2005, have historically preceded infestations of local waters. In other words, these peculiar beings, which have a life span of less than two years, seem on their way to establishing residence along the length of the eastern Pacific.

"We really need to mount a research initiative soon," warns William Gilly, a professor at Stanford University's Hopkins Marine Station.

The reasons for the phenomenon have not been pinned down, although gradual ocean warming, pollution and over-fishing of large predators are suspected factors.

Nor is it known what the ramifications might be. But there is already proof that the squid are ingesting small rockfish, anchovies, sardines and much smaller market squid, which is the type prized as calamari.

IN fact, very little is known about Humboldt squid because they spend most of their lives at depths of 650 to 3,000 feet.

But when they rise, they can provide some big surprises.

Four divers found that out when they tried to document the squids' behavior in the Sea of Cortez 17 years ago. While a non-diving passenger battled to land a 14-foot thresher shark on rod-and-reel, Alex Kerstitch of Arizona and three friends submerged in the nighttime sea, carrying cameras. The divers settled near the dim fringes of the boat's lights. They could see the weary shark being pulled toward the boat. Below, dozens of squid began flashing iridescently, red-white-red.

The flashing is carried out via millions of chromatophores within the skin, opened to reveal red, closed to reveal white; it is believed by some scientists to be a means of communication.

A five-foot squid flung itself onto the shark and tore an orange-sized chunk from its head....

Gilly has learned that Humboldt squid thrive in this oxygen minimum layer, or OML, generally at great depths. The OML contains tiny lanternfish, on which the squid rely for sustenance.

In addition, Gilly says, "Inhabiting the OML may protect juvenile or smaller Dosidicus gigas from predation" by other fish.

Furthermore, large sharks were becoming scarce because of over-fishing in the Sea of Cortez, and this might have favored the cephalopods.

A squid-fishing industry established at Santa Rosalia on the Baja California coast north of Loreto has flourished in the last decade. Hundreds of skiff fishermen depart nightly during the summer, and use multi-pronged jigs and monofilament lines to haul the beasts up, hand-over-hand.

The fishery processes 100,000 tons of squid annually, most going to Asian markets, although U.S. markets are being explored.

Gilly has estimated that 10 million squid occupy a 25-square-mile area beyond Santa Rosalia....