'Shark was crunching my chest:' Swimmer describes encounter with great white (VIDEO)

Steve Robles recovered at his Lomita home with his wife, Glenda Robles (left), after he was attacked by a shark on July 5, 2014. (Photo: KTLA)

LOS ANGELES (CNN) -- Nightmares and a panic attack haunted Steven Robles after a great white shark attacked him at a Southern California beach Saturday, but he was out of the hospital Sunday.

Robles, 40, was weak and sore a day after the attack near the Manhattan Beach pier, he told CNN.

Robles said he was in a "complete state of panic" when he came face to face with the 7-foot shark, but "pure instinct" kicked in. "I saw this shark eye to eye, staring at me as it was crunching into my chest." He grabbed its nose and pried it away from his chest, he said.

The shark, which a fire official said was a juvenile great white, immediately swam away and did not return, Robles said.

The great white was apparently agitated after struggling for its life for the previous half hour before the attack on Robles. A fisherman who used chum to attract sharks to the pier had cut it loose after hooking it but failing to land it, Robles said.

WATCH: Swimmer describes his encounter

Marine biologist Eric Martin told CNN affiliate KABC that it likely was a "response bite" by the juvenile shark and "the swimmer just happened to be at the wrong place at the wrong time."

"I thought 'Oh, my God, this is it, I'm gonna die," Robles said. But the shark's bite was not deep, sparing Robles' ribs and organs, he said.

"It wasn't a full-size bite," said Capt. Tracy Lizlotte, a lifeguard for the Los Angeles County Fire Department.

The scars to his psyche may be deeper. Robles, who would swim two miles from the Hermosa Beach pier to the Manhattan Beach pier each Saturday, said he is afraid to go back into the water.

"I hope I do someday, but it's off the table right now."

He spent a restless night Saturday, waking up from nightmares, he said.

The aftermath of the attack was recorded on cell phone video by someone on the beach who was alerted by the screaming. CNN affiliate KTLA posted the video on its website. It shows a group of swimmers frantically trying to reach shore with the victim screaming loudly from the water and people on the pier urging him to hurry, yelling that the shark was still close by.

WATCH: Cell phone video captures scene

Manhattan Beach Pier has been closed until Tuesday, police said in a news release.

There are plenty of great white sharks in the Southern California surf, but they pose no danger to beachgoers, according to Randy Hamilton, a shark expert with California's Monterey Bay Aquarium.

"I just go back to the last 50 years on how many great white sharks have actually caused a death in Southern California," Hamilton said in a CNN interview in December. "I only know of one incident where someone got a nip on the foot."

The great whites around Southern California are juveniles, also known as "young of the year." At less than 18 months old, they only eat fish, Hamilton said. When the sharks approach adulthood, they relocate to the cooler waters near San Francisco, where they change their diets to mammals -- sea lions and seals, he said.

Shark attacks are still pretty rare, but they have increased at a steady rate since 1900, "with each decade having more attacks then the previous," according to statistics from the International Shark Attack File based in Gainesville, Florida.

ISAF says on its website that in 2013 there were 72 unprovoked shark attacks on humans, actually the lowest number of global attacks since 2009, when 67 attacks occurred.

The research organization emphasized on its website that an increasing number of shark attacks doesn't mean the rate of attacks is increasing. ISAF research shows people are spending more time in the surf, which increases the interactions between humans and sharks.

CNN's Anne Woolsey,Janet DiGiacomo and Greg Botelho contributed to this report

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