Dusty Payne exits the water of Ocean Beach after his
shark sighting. Photos: Rip Curl / Nate Lawrence

Kelly Slater is mobbed after his first round heat.
Photo: Rip Curl / Lawrence

Kelly Slater was in-form in his Rd 1 heat win. One
more needed to claim his 11th world title. Photo:
Rip Curl / Mike Smolowe

Ocean Beach's aggressive barreling waves and
shifting sands make for challenging conditions.
Photo: Rip Curl / Nate Lawrence

A seal and a surfer look very similar from a shark's
point of view.Pro surfer Dusty Payne exited the water in the final minutes of his first heat at the Rip Curl Pro Search contest at Ocean Beach in San Francisco after spotting what he claimed was a large Great white shark in his vicinity.

He described "the biggest fin I've ever seen in my life coming at me." Payne, 22, from Hawaii, had no doubt in what he saw, "I've seen dolphins and it wasn't a dolphin."

Shark activity is high this time of year near the waters around San Francisco, in an area known as the red triangle, which extends from Bodega Bay, north of San Francisco, offshore past the Farallon Islands, and south to Big Sur, near Monterey.

The cool autumn waters promote feeding activity for seals and sea lions, which then attract the large predatory fish like the Great White.

The Rip Curl Pro is hosting the world's top competitive surfers this week and is one of the last stops of the 2011 ASP World  Tour. Ten-time World Champion Kelly Salter won his Round 1 heat today and can clinch an unprecedented 11th world title if he wins his Round 2 heat tomorrow.

Anticipating his 11th title Slater was characteristically calm.

"I've been pretty relaxed actually. It's the type of situation where you could get tense but I've been focused and relaxed.  I'm just gonna go do my job, I just need 4 good waves in each heat," Slater said.

Today's shark encounter marks the third incident in California involving Great Whites in the last five days. On Monday surfer Brent Manion, at Beacons Beach in San Diego claimed that a 10-12 foot Great White circled his board around 3pm, after which he paddled immediately towards shore. Lifeguards confirmed his report, "He saw the shape of the nose, and a vertical tail fin."

Last Saturday 27-year-old Eric Tarantino was attacked near Monterey by a large white shark. The animal bit the surfer's upper torso including neck, shoulder and forearm inflicting a number of deep wounds. Fortunately Tarantino escaped critical injury. He is expected to make a full recovery after doctors repaired his wounds during a 2-hour surgical procedure.

Experts think sharks attack surfers because they mistake them for the natural marine mammal prey. From the sea floor a surfer's silhouette looks very much like that of a seal.

The Rip Curl Pro is scheduled to begin with Round 2 action at 8 a.m. Wednesday.