A surfer at Pleasure Point -- between Santa Cruz and Capitola -- reported spotting a shark Saturday, authorities said.
The sighting was reported about 9 a.m., according to the Santa Cruz sheriff's office.
According to a Santa Cruz sheriff's Facebook post, "the surfer reported seeing a shark's dorsal fin just outside the second break approximately 100 feet from shore."
The surfer told authorities he thought the shark measured between 12 and 15 feet.
Great White Sharks have been spotted off the Northern California coast for years and the species is thought to be about 16 million years old, according to Wikipedia.