Jumbo squid rising from the inky depths in Southland waters

The barracuda mystery was solved in a day.

The popular game fish flooded into Santa Monica Bay last Friday, thrilling holiday weekend anglers.

They all but vanished Monday.

Tuesday, fishermen dropping lures intended for 10-pound barracuda instead latched onto 30- to 40-pound Humboldt squid.

“I don’t know if it’s a coincidence or what,” said Rick Oefinger, owner of Marina del Rey Sportfishing. “But we had a big jag of barracuda out there and on Monday there weren’t any left.”

Humboldt or jumbo squid, referred to incorrectly by some as giant squid, are voracious predators that live by the thousands at depths of 600 feet or more, and rise at night to feed.

Barracuda had been over that deep water, on the fringes of drop-offs, and probably were frightened off by the squid.

Humboldt squid have been targeted offshore for the last two weeks by twilight boats out of San Diego and Orange County.

This same phenomenon occurred in late February, with the squid showing first down south and then off Palos Verdes.

This time, however, they might also have been foraging for grunion in the surf.

Chris Lindeman discovered squid while stalking grunion near his Newport Beach home. A barely live specimen had three grunion stuck to its tentacles.

Hoping to free a wriggling grunion, Lindeman touched the squid and it “flashed red through its body.” Squid do that, scientists believe, as a means of communication or as a warning.

It was the second time Humboldt squid had been linked to grunion runs. The other was in 2002 off San Diego.

Because the predators return to darker depths before daylight, they are not considered a threat to swimmers.

Late-night grunion hunters, however, might use caution while wading. Grunion are expected to run again, for four consecutive nights, beginning tonight.

Calamari for wolves

It’s becoming increasingly likely that highly adaptive Humboldt squid, common from Peru to Baja California, are expanding their territory.

The stranding of squid in large numbers -- nearly 400 were picked up this week in Orange County, and there have been similar incidents in recent years -- has historically preceded settlement.

Mass wash-ups of dead squid occurred sporadically in the Sea of Cortez years before they became year-round residents there.

Specimens have been found recently off Oregon and Washington, and two years ago they drifted ashore for the first time off British Columbia. That was a surreal scene worthy of the Nature Channel:

“North coastal British Columbia, late summer, 2005. Wolves on weather-worn Dewdney, Banks, Porcher and Pitt islands are sought by researchers with the Raincoast Conservation Society....

”... On Dewdney Island, scientists almost literally trip over freshly dead squid, still purplish and iridescent, thousands of miles beyond their known range.

“Excursions to other islands reveal similar findings. But it is ‘not until Banks Island where we found evidence of wolves dining on calamari,’ Chris Darimont later recounts.

“At a known wolf rendezvous site, the team discovers squid carcasses strewn about the forest, and wolf pups scampering around with tentacles dangling from their jaws. Some of the pups are dragging squid carcasses as large as themselves across the sand.”

There have been no known stranding incidents since.

Blue whales in O.C.

Blue whales are lingering off Dana Point, as they did for an extended period last year, providing glimpses of the largest animals known to have inhabited the planet.

Though they grow to 100 feet and can weigh 150 tons, blue whales prey almost exclusively on tiny shrimp-like krill and their presence is not related to that of Humboldt squid.

Dana Wharf Sportfishing and Capt. Dave’s Dolphin Safari are among companies running blue whale excursions.

Irvine Lake blues

Irvine Lake on Thursday stocked 5,000 pounds of blue catfish weighing 20-plus pounds. An additional 5,000 pounds of much smaller channel catfish will be stocked next week.

(The blue catfish wear tags indicating that they must be released.)

Beginning next Friday, the Silverado reservoir will remain open till 2 a.m. on Friday and Saturday nights.

Mexico, sharks

and long-lines

Facing strong opposition to the passing in Mexico of NOM-029, which regulates a previously unregulated shark fishery and allows extensive long-lining as close as 15 miles from shore, the country’s agriculture and fishing commission, Conapesca, issued a press release, saying that it would support various modifications.

Among them: forbidding the commercial marketing of billfish and dorado, or mahi-mahi; setting bycatch limits, and establishing regionalized fishing areas.

Though marlin and dorado have for years been reserved for sportfishing, they’ve commonly been caught as bycatch and sold to restaurants.

Legally, a year must pass before modifications are put into effect.

Closing with a quote

Bass-fishing pro Gerald Swindle after being eliminated in the semifinals of the recent Bassmaster American tournament at Greensboro, N.C.:

“I feel like I’ve been double-dipped in peanut butter and rolled down a dirt road.”

pete.thomas@latimes.com