A San Diego County beach is open again after being shut when a shark was seen circling kayakers.

The 1 1/2-mile stretch of beach from La Jolla Cove to Scripps Pier reopened at 7 a.m. Sunday.

San Diego Fire-Rescue spokesman Lee Swanson says the beach will remain under a "shark advisory." That means lifeguards will warn beachgoers about the Saturday sighting of the 8- to 10-foot hammerhead shark.

Swanson said Saturday that the shark appeared to be acting aggressively toward a group of kayakers and followed them into shore.

Lifeguards reviewed a video taken by a kayaker of the shark and ordered the beach closed. A marine biologist at the nearby Scripps Institution of Oceanography confirmed that the size, species and behavior of the shark warranted the closure.