California State Parks said in a news release the 26-year-old man was surfing off Manresa State Beach on the northern end of Monterey Bay in Santa Cruz County around 1:30 p.m. when he was attacked by an "unknown shark species."
"State Parks expresses its deepest sympathy to the family of the victim," the agency said.
The 26-year-old man was pronounced dead at the scene. The victim's name has not been released. Deputies from the Santa Cruz County Sheriff’s Department notified the man's family.
"The type of shark species that attacked the victim is unknown," the statement said.
One woman who lives near the state beach told KRON-TV that shark activity was common in the area, but news of the fatal attack was "terrifying."
“It makes me horribly sad,” she said Saturday. “I love the ocean and I hate for people to be scared of it.”
In the wake of the attack, the water 1 mile north and south of the attack will be closed for five days and not reopen until Thursday.
Signs were posted warning beachgoers about the attack on access points and beach entrances within a 1-mile radius of the incident, according to KTVU.
The sign said the attack happened within 100 yards offshore and that water sports and activities are "highly discouraged."
"With the exception of water sports, Manresa State Beach is fully closed from 11 a.m. to 5 p.m. daily, meaning there is no public access during this time," state parks said.
Surfing and swimming activity has been steady while local officials have closed the beach every day between 11 a.m. to 5 p.m. to deter a surge of visitors to the coastline to avoid spreading coronavirus.
Monterey Bay drone photographer Eric Mailander told KRON-TV he has been observing dozens of great white sharks swimming near the shoreline in recent days. He said he counted 15 sharks while out on his boat Saturday morning.
None were showing signs of aggressive predatory behavior, Mailander told KRON on Saturday.
The Associated Press contributed to this report.