A few sharks spotted about 250 to 300 yards offshore at Jones Beach State Park prompted officials to halt swimming from 8:15 a.m. until 5 p.m. on Tuesday.
Only wading up to the waist was allowed to resume, approximately two hours after the last shark was sighted and one day after a lifeguard possibly was bitten at the beach.
Parks officials stepped up patrols — by air, land and sea — and increased drone flights following the sightings, the first of which were at 8:15 a.m., before continuing off and on throughout the day, according to George Gorman, Long Island regional director for the state parks system.
Swimmers at state parks are usually not allowed back in the water until at least an hour after a shark is seen, according to Gorman.
Before opening any beach daily, lifeguards check the conditions — from rip currents to the presence of any sharks.
Just last week, Nassau County outlined increased shark patrols, as biologists say Long Island's cleaner waters are attracting both prey fish and their predators.
State police officers on Tuesday were scanning the Atlantic Ocean by boat and helicopter, and both the state police and lifeguards were flying drones.
"And they have confirmed the sightings from this morning," Gorman said.
He said two species were identified: sand and thresher sharks. Adult sand sharks can reach about 10 feet in length; threshers around twice that, experts say.
Large schools of bluefish and bunker fish have been observed in both the drone footage and by the helicopter patrol as they are swimming closer to shore than usual. This appears to be drawing the sharks.
"We also have seen stingrays," Gorman said, "and a fish called a Cobia that is usually in southern waters."
"It's marine life; what's unusual is that they are closer to shore than we would normally see them."
Cobia, which can grow to about six feet, are "most abundant from Virginia south through the Gulf of Mexico," according to the National Oceanic and Atmospheric Administration website.
On Monday, a lifeguard went to the hospital for an inch-long gash on his left calf to be treated. Police said he reported that he felt a tug and saw a fin which he believed to be that of a shark. No further details about his condition were released.
Last week, three sharks seen near two Nassau ocean beaches prompted Nassau County Executive Laura Curran on Friday to announce increased helicopter and marine patrols in case these predators — for the second year in a row — visit Long Island's cleaner seas more often.
The state parks department on Tuesday announced several additional steps, including adding lifeguards, increasing patrols by them and by park workers and park police, sending lifeguards and park police out in boats, and flying more drones and a state police helicopter.
"Long Island beaches are a crucial resource for New Yorkers in summer, and we must make sure people feel safe when visiting," State Parks Commissioner Erik Kulleseid said in a statement.
"With assistance from New York State Police, we are expanding our measures to patrol for sharks and other potentially dangerous marine animals," he said.