Vandenberg Air Force officials have closed three beaches after a surfer was attacked by a great white shark Thursday evening.
The surfer suffered non-life threatening injuries to his knee, as well as cuts to other parts of his body, in the attack, which occurred about 5:30 p.m. a quarter-mile north of Wall Beach, officials said.
Ralph Collier, president of the Shark Research Institute, said the shark was 8 to 10 feet long.
The confirmed attack prompted Vandenberg Air Force Base to close Surf, Wall and Minuteman beaches for 72 hours. The order will be lifted at 4 p.m. Sunday, according to a statement from the base, which is north of Lompoc in Santa Barbara County.
Officials at the base asked the public to avoid the beaches "due to safety considerations."
Collier said he plans to examine the surfer's surfboard, which was scraped, to get more information about the shark in the attack.
With more beachgoers heading to the shore and a main food source -- seals and sea lions -- on the upswing in California, the chances of a shark encounter have jumped, he said.
"I am surprised we don't have more events like this," Collier said.
Still, shark attacks remain extremely rare: Someone is more likely to die by being struck by a falling coconut than being attacked by a shark, Collier said.
Officials have logged 50 to 100 shark attacks per year worldwide since record-keeping began, he said. Of those attacks, only eight to 12 have been fatal.