HEMPSTEAD, N.Y. (CBSNewYork) -- Some Nassau County beaches were closed to swimmers after shark sightings.
There have been at least three shark sightings Monday.
One took place at Lido Beach in the morning. Officials took no chances, putting up red flags, and saying that bathing isn't allowed.
Monday morning, Lido beachgoers were escaping the heat at around around 10:15 a.m. in Hempstead.
"All of a sudden the lifeguards stood up and starting blowing the whistles," one person said.
It was lifeguard Logan Fitzgerald who was patrolling the waters on his surfboard when he saw a telltale dorsal fin.
"It came out, shot out of the water, spun around, just didn't look like a dolphin. Fin - definitely a shark," he told CBS2's Carolyn Gusoff.
Officials call it a sizable shark, likely a 7'-12' bull shark, swimming a stone's throw from the shoreline.
"Eight to ten feet out. So it was pretty close, folks. That is really close to the shore line," said Hempstead Town Supervisor Don Clavin.
Beaches for 13 miles - from Atlantic Beach to Jones Beach - were closed to bathers for hours, then reopened for wading, only to be closed again after a second sighting of a bull shark off Long Beach.
"This is something we haven't seen down here in a number of years. Size of it was a concern. The staff haven't seen a shark this size in quite a long time, if ever, and this is just out of an abundance of caution to the residents for their safety," Clavin said.
An uptick in shark sightings, possibly due to the heat. Over the weekend, two thresher sharks were seen off Robert Moses, and the ominous bite marks found this weekend in marine life.
"There's whales, dolphins and this is just something else that's in the ocean that we have to be aware of and know it's out there," said Town of Hempstead Chief Ocean Lifeguard Mike Romano. "A bull shark in this territory, this far north, we take, consider as a concern."
For the few hours swimmers were allowed back in the water, many said "no thanks."
"I don't want to go in the water today," one person said.
"I've never seen one before, so it was pretty cool, honestly. But kind of scared after I realized I should get out of the water," said another.
More lifeguards are on boats, Nassau County police and Coast Guard are patrolling.
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