The Coast Guard began searching for possible missing people after a capsized vessel was found near Pigeon Cove in Pescadero Monday.
Bystanders reported to authorities around 11 a.m. that an 18 to 20-foot boat had capsized.
A Coast Guard helicopter crew and boat crews searched the area and found the boat, but didn't find any people. Responding agencies determined the boat was likely a panga.
Officials have seen a trend of smugglers coming from Mexico in panga boats, traveling farther north along the California Coast, taking longer routes and greater risks to evade patrols, Coast Guard officials sais.
"Fast 25- to 50-foot open-hull boats powered by two or more outboard motors, commonly referred to as 'pangas,' are used by smugglers to transport illegal drugs and people into the United States," said Capt. Greg Stump, Coast Guard Sector San Francisco commander.
The public is urged to report suspicious maritime activity by calling 911, or call the Department of Homeland Security Tip Line at 415-426-8815. All calls to the Tip Line are confidential and callers may remain anonymous.