Experts warn more shark attacks possible in Southern California

NEWPORT BEACH, Calif. -- There was still no swimming allowed Tuesday at the Southern California beach where a shark attacked 52 year old Maria Korcsmaros on Sunday. She was training for a triathlon, swimming about 500 feet off shore when the shark struck.

"She had extensive lacerations to her right arm," said Dr. Humberto Sauri, who treated Korcsmaros.

Sauri said Korcsmaros will survive, but that the shark left a very large bite mark.

"It extends from the upper torso area down to the pelvis," Sauri said.

"A lot of these sharks spend most of their time literally 100 feet off the beach," said marine biologist Chris Lowe, who has been tracking the growing shark population off Southern California for more than a decade.

In 2014, Lowe showed CBS News how his team is using underwater drones to follow and observe sharks.

He said the number of juvenile great white sharks in the area is rising significantly. They're drawn to warm water caused by El Nino and an abundance of fish to feed on. They also have no predators, and great whites are a protected species.

"The questions that we're trying to answer now are, why are they at these beaches, how long do they stay at these beaches, what makes this beach so much more special than that beach?" Lowe said.

According to Lowe, the six- to seven-foot-long juvenile great whites are skittish and usually stay away from swimmers.

But with more sharks and more people in the water, "I think the rate of shark attack is going to continue to go up," Lowe said. "And the reason for that is simple math."

Doctors said the bite mark Korcsmaros suffered was about 18 inches wide, meaning it was likely caused by an adult great white shark at least 10 feet long -- extremely rare in these waters.