LOS ANGELES — They're large enough to fit an African bull elephant in their mouths. Loud enough to rival a 747 jet. And lithe enough to ply any ocean.

And the mighty blue whale, the world's largest mammal, is having a whale of a year off the coast of Southern California.

"It's looking like it's shaping up to be one of the best blue whale seasons ever," said Alisa Schulman-Janiger, a naturalist with the Los Angeles-based American Cetacean Society, who has guided whale-watching tours for three decades.

"From what I hear, the numbers just keep increasing daily. It could be a record year."

The chance of beholding the behemoths now feeding in the Pacific Ocean from San Diego to Santa Barbara is greater than ever, whale watchers and tour operators say. The breathless bounty could last until November.

Blue whales migrated early this year from Mexican waters to Southern California in search of thumb-sized, shrimplike krill.

And humpbacks, normally seen in spring, are also hanging out to feed in huge numbers.

And nowhere offers a richer krill table — and a chance to watch blue whales devour 4 tons a day apiece — than the Santa Barbara Channel.

Each time he heads out, whale-tour skipper Mike Connally spots at least five blue giants off the Santa Cruz or Santa Rosa islands.

On one recent trip, gawkers marveled at a pod of 22.

"It's a good season. It's constant sightings," said Connally, co-owner of Island Packers, with boats out of Oxnard and Ventura. "We don't have to hunt very far. We've had really good krill blooms, which is causing a lot of feeding."

Once hunted to near extinction for their oil in the 1900s, blue whales now number less than 10,000, scientists say.

Measuring up to 100 feet and weighing up to 200 tons, the endangered animals can emit one of the loudest calls in nature, up to 190 decibels, capable of signaling other whales more than 1,000 miles away, Schulman-Janiger said.

"You don't hear it, you feel it," she said. "Your teeth rattle. Your bones rattle. It's like a real low bass, louder than a jet engine."

A fully grown blue whale, with a heart the size of a Volkswagen Bug, could open its jaws wide enough to envelope a bull elephant, she said.

When it slowly flukes, its tail can span 25 feet, loosing a cascade of water like Niagara Falls.

The American Cetacean Society, which advocates for whales, dolphins and porpoises, will host whale-watching tours Saturday and Aug. 15, the same day as the next Island Packer trip.

They may not have to sail far to see leviathans. At least a whale a day is seen as close as a mile off San Pedro. And up to a dozen a day are tallied off Santa Barbara.

"It is better than anybody ever remembers," said Bernardo Alps, president of the society's L.A. chapter, who has been whale watching each weekend. "It is really spectacular.

"It's absolutely incredible to see a blue or humpback whale lunge at krill and fill its mouth on the surface."