A sheriff's helicopter crew warned a group of paddleboarders to exit the water after spotting more than a dozen great white sharks along the Southern California coast.

Sheriff's video obtained by the Orange County Register shows about 15 sharks swimming near paddleboarders Wednesday at Dana Point south of Los Angeles.

From the helicopter a deputy alerts the paddleboarders and tells them to leave the water calmly.

Advisories have been posted for beaches up and down Southern California after shark sightings this week - including at San Onofre State Beach, where a woman was bitten by a shark April 29.

Lifeguards say there have been no reports of swimmers or surfers being bumped or charged.