NEWPORT BEACH, Calif. — More than 1,500 jumbo squids — common to South America — have washed onto Orange County beaches in the past few days, leaving marine experts perplexed as to why so many of the torpedo-shape mollusks have traveled so far north.

"We've known that there's something peculiar going on with those species," said John McGowan, professor emeritus at Scripps Institution of Oceanography in La Jolla and one of the leading oceanographers on the West Coast.

Dotting Crystal Cove State Park beach up to Newport Beach, the dead creatures with their elongated, gooey-looking tentacles and oversize heads have caught beachgoers off-guard, said Eric Bauer, Newport Beach lifeguard captain.

"They look like a miniature sea monster, something you'd see out of a Jules Verne novel," he said.

Unlike their smaller cousin — known to most people as calamari — the beached and mostly juvenile pink-and-black creatures are about 3 feet long and 5 to 15 pounds. The Dosidicus gigas, also known as the Humboldt squid, are not recommended eating. Adults can grow to 6 feet long and weigh up to 100 pounds.

The creatures are typically found off Peru and elsewhere in South America, but in recent years they have been turning up in larger numbers in the Gulf of California, and waters off Oregon and Alaska.

McGowan called the recent stranding "dramatic" but said marine experts don't know much about the squids, including why they've reached Southern California.

"These things are invading, and we don't know what's going on," he said. "It may be they're following a warm California current. Oceanographers don't have a clue why a large population of squid like this is moving north or why they strand themselves."

Linda Blanchard, laboratory director at the Ocean Institute in Dana Point, said recent articles in scientific and wildlife journals suggested the big squids were migrating because with sharks and other large predators being depleted by fishing, squids can forage without a threat.

"The belief is that with the heavy fisheries, especially in the Sea of Cortés [Gulf of California], focusing on sharks and big tunas, that maybe the big squids are coming in to fill that gap," she said.

About 500 jumbo squids were found Tuesday and Wednesday along a 6-mile stretch of beach in Newport Beach.

At Crystal Cove State Park, more than 1,000 creatures — some weighing 15 pounds — were stranded both days, with smaller squid sightings in Laguna Beach and a single jumbo at San Onofre State Beach in San Diego County.

"These were substantial," said Ken Kramer, Crystal Cove state superintendent. "They're in the 10- to 15-pound range. The seabirds are having a feeding frenzy."

For beach maintenance officials, the jumbo squids are a headache.

Dave Niederhaus, Newport Beach maintenance director, said that because of the recent Southern California storms, his crews have picked up 400 to 500 tons of debris that washed ashore.

"We've found dead raccoons and other animals. I would prefer picking up seaweed instead of these squid because even dead, they squirt you with ink," Niederhaus said.