Shark attack: Surfer seriously injured after being bitten by great white while swimming in California

The 39-year-old was able to swim to shore, where bystanders treated a leg injury

A surfer was hospitalised on Saturday after being bitten by a great white shark at Gray Whale Cove State Beach in Half Moon Bay, California. (CAL FIRE San Mateo)

A 39-year-old surfer in Northern California is in serious condition after a great white shark bit him on the leg at Grey Whale Cove State Beach, just south of San Francisco.

The man was bitten around 9.15am by a six to eight foot great white, according to the San Mateo County Sheriff’s Office.

Bystanders said they spotted the man swimming to shore and falling onto the beach as blood poured from his leg.

"He called out to me, then collapsed," Thomas Masotta, who was fishing onshore, told NBC. "He was rolling around on the ground and said he wasn’t in a lot of pain but was worried that he was losing a lot of blood."

Mr Masotta tied off the leg wound with a backpack strap then called 911.

Heavy fog around the beach complicated rescue efforts, making it hard for rescue helicopters to land. Firefighters had to carry the wounded man up a steep stairway, where emergency responders were waiting alongside Highway 1.

Authorities shut down the beach for the time being, and the man was taken to Zuckerberg San Francisco General Hospital’s trauma centre, having lost a pint of blood on the beach.

Bystanders said they would be afraid to go back to the beach.

"Yeah, terrifying, I’ve seen Jaws I know what they can do, it’s crazy," Marcel Madison, of Sacramento, told ABC7 News.

Shark attacks of all kinds are extremely rare and rarely fatal. Since 1905, there have only been 194 shark incidents in California involving all species of shark, according to the California Department of Fish and Wildlife, most involving white sharks. Only 14 of those incidents were fatal.

“It is important to note that while human beach use and ocean activities have greatly increased due to the growing population and greater popularity of surfing, swimming, and scuba diving, shark incidents have not increased proportionally,” the department says on its website. “This is even more evident when looking at incidents where a person was injured.”

According to one research project, the chances of being bitten by a shark are 1 in 11.5 million. The most dangerous part of an ocean swim, in other words, is the drive to the beach.

Nonetheless, humans kill about 100 million sharks a year, out of a mix of commercial interests and cultural fears of the imposing predators, often driven by movies like Jaws and sensational media coverage.