APTOS (CBS SF) — Over a dozen great white sharks continue lurking near the shoreline at a Santa Cruz County beach.

About 15 have been close to Seacliff State Beach in Aptos for the past five days. No aggressive shark behavior has been reported so far.

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The Pelagic Shark Research Foundation believes the sharks are about two or three years old, and less than ten feet long. The largest shark in the group was seen swimming near Capitola on Tuesday, while the rest linger near the cement ship in Aptos.

“What is significant is not that these are great white sharks, but that this is a gaggle of pups,” Pelagic Shark Research Foundation director Sean R. van Sommeran told KSBW. “This is the furthest north a rookery has assembled.”

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WATCH: Aerial View Of Great White Sharks At Seacliff State Beach

Lifeguards say beaches will not be closed until there is a dead seal or other signs that the sharks are feeding.

KSBW reports beachgoers are still swimming despite the shark warnings.

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The NorCal Junior Lifeguards competition was called off last week due to the sighting.