Huntington Beach authorities Monday closed access to the waters off Sunset Beach, between Warner Avenue and Anderson Street, following a shark sighting.
A beachgoer flagged a lifeguard between 12:30 p.m. and 1 p.m., saying a shark had been spotted, said Jennifer Carey, a spokeswoman for the city of Huntington Beach.
The shark was estimated to be between 8 and 12 feet, Carey said.
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"Based on those sizes, it may not be a juvenile shark,'' Carey said.
The city has a policy that if a shark shows aggressive behavior or is a certain size, then the waters are closed for at least four hours, Carey said.
Access to the water could be reopened between 5 p.m. to 6 p.m., Carey said.
Visitors to the beach should check safebeachday.com for updates, Carey said.