Pacifica police Capt. Joe Spanheimer said the man was fishing off Pacifica State Beach around 4:55 p.m. when a shark approached, "bit the kayak, then briefly circled around the craft before swimming away," the San Francisco Chronicle reported Wednesday.
Spanheimer said authorities are not sure what kind of shark it was, possibly a great white, which are more common along the Bay Area's ocean coast when the water is warm during the summer and fall.
The captain said signs were being posted at the beach to inform people of the encounter.
Notable deaths of 2014 [PHOTOS]