Persistent sightings have some calling for an expedition to determine how many of the predatory creatures exist in Canadian waters.

VANCOUVER - When British Columbia's hake fleet sets off to trawl the deep ocean off the West Coast later this month, the crews will be on alert for a strange, voracious squid that is invading the north Pacific.

The Humboldt, or jumbo squid, is usually found off Mexico, but there is a heightened alert on the B.C. fishing grounds this year because the species has been making its way up the coast of North America, devastating hake stocks as it goes.

"I don't know much about them but they sound like quite a predator," said Brian Mose, director of the Deep Sea Trawlers Association of British Columbia.

Mr. Mose is sending a message to all fleet members, asking them to report any encounters they have with the large squid, which has been expanding its range both north and south.

Last year, researchers reported a breeding population had become established off the coast of central California, where it has been linked to a crash in hake stocks.

Off the coast of Chile, where prior to 2002 it was seldom seen, the squid is now supporting a commercial harvest of about 200,000 tonnes annually.

Jim Cosgrove, recently retired manager of natural history at the Royal B.C. Museum, said there have been so many persistent reports of jumbo squid in northern waters that it's time a research expedition was sent to determine how many there are and where they are roaming in Canadian waters.

The range expansion of jumbo squid, he said, appears linked to warming ocean temperatures and it could have both good and bad side effects.

On the positive end, if enough squid move into the north Pacific, it could launch a lucrative commercial fishery, as it did in Chile.

But at the same time there are concerns about the impact it will have on hake, and possibly on stocks of wild salmon.

"The Humboldts generally are taking smaller fishes ... but I don't think they'd be fussy. If they could catch [a salmon], they would eat it," he said.

Mr. Cosgrove said he first took note of the growing presence of jumbo squid in the summer of 2004 when a fisherman e-mailed him a picture of a "strange squid" caught in Alaska.

He recognized it immediately as Dosidicus gigas, the jumbo squid that grows to more than two metres in length, weighs up to 50 kilograms and swims up to 24 kilometres an hour, snaring its prey with suckers edged with teeth.

"Two things were very unusual about this find," he would later write in a report. "One, Humboldt squid seldom come farther north than central California, and this picture was taken near Sitka, Alaska. Two, if there were Humboldt squid in Alaska there were sure to be Humboldt squid in British Columbia too."

It didn't take long for his suspicions to be confirmed.

A few weeks later a sports angler trolling for salmon off the south coast of Vancouver Island felt an unusual jolt on his rod, and played a thrashing squid to the net.

Gudmund Gudmundseth's catch went into the books as the first jumbo squid specimen ever retained in B.C.

The reports were fast and heavy after that, and Mr. Cosgrove was left with no doubts that there were a lot of jumbo squid in northern waters.

Captain Alan Otness of the fishing vessel Commander saw "hundreds, if not thousands of these squid" hunting baitfish.

On the U.S. research vessel Maurice Ewing, scientists were peering over the side at night as sediment cores were pulled up in the Gulf of Alaska, when strange creatures began flashing through shafts of light in the dark water.

"A school of large squid suddenly appeared, perhaps a hundred in number ... and initiated a feeding frenzy upon the baitfish. ... The water was literally churning as the squid chased the baitfish, their tentacles reaching up above the surface of the water," reported an oceanographer in an e-mail to Mr. Cosgrove.

Some crew members speared a few of the squid and a positive identification was made. They were Humboldts.

At about the same time, a commercial fisherman off the south coast of Vancouver Island reported seeing a school of thousands of squid resting on the surface at night.

Sightings have continued.

"There are a lot of reports that they have been seen off Tofino and elsewhere this year," Mr. Cosgrove said.

But Eric Hochberg, curator of invertebrate zoology at Santa Barbara Museum of Natural History, said it is too soon to tell if the expansion of the jumbo squid is just a temporary phenomenon, brought on by warmer ocean currents, or if a permanent population has been established.

He said that dating back to the mid-1800s there have been occasional sightings of jumbo squid as far north as Alaska.

Typically, he said, there would be a flurry of reports along the coast, then the squid would vanish, before reappearing decades later.

One possibility is that the squid expand their range whenever intermittent El Nino events push warm water north, and then they retreat when colder water returns.

"We still have a lot of questions," Mr. Hochberg said.