Shark attacks are on the rise along the California coast.

"Beach access to the water is closed today because we had a girl get bit by a shark," said one park official.

Beachgoers were greeted by scary warning after 35-year-old Leeanne Ericson was attacked in knee-deep water north of San Diego last week.

"It was a large wound," said her surgeon, Dr. Gail Tominaga.

Tominaga said Ericson likely survived because of quick action on the beach.

Shark attacks and shark sightings are on the rise along the Calif. coastline. CBS News

"That was crucial because they were able to put a big dressing on and a partial tourniquet on to help the bleeding, you know, decrease the bleeding," Tominaga said.

Marine biologist Dave Bader of the Aquarium of the Pacific said that in his experience, a shark is never intentionally going after a person.

"We know what great white sharks like to eat and especially as juveniles, we know they like to eat small fish," Bader says. "Nothing on you looks like a small fish."

But there have been an increasing number of shark sightings in southern California, including one breaching near surfers ealier this week.

One marine biologist says shark attacks are on the rise in southern California due to better conservation. CBS News

Most of them are young great whites, some six feet long and just a year old, according to marine biologist Chris Lowe.

"I attribute a lot of that to better conservation, we protected white sharks 20 years ago in California, their food source has come back, and in many ways, our coastal oceans are getting healthier," Lowe says.

But frequent shark sightings are causing fear.

"It was beyond the most terrifying experience of my entire life," says Sophia Raab, 18, who believes she may have been bitten last Wednesday while surfing back to shore north of Los Angeles.

"I looked down and my leg was opened in half," she said. "And I just began screaming bloody murder."

Doctors told Sophia Raab, 18, that she was bitten by a shark but shark experts say she was more likely cut by a surfboard fin. CBS News

Doctors told her it was a shark bite, but from the look of the wound, shark experts say she was more likely cut by a surfboard fin.

Marine biologists say the fear generated from these incidents is a reminder that even with crowded beaches in southern California, what lurks beyond the shoreline is mostly unknown.

"It is wild. There is wild life there and certainly we have to respect that," Bader says.

Doctors say Ericson has already had two surgeries and will need at least two more. It's not clear when she'll be out of the hospital, but doctors do think she will be able to use her leg again.