The Town of Hempstead closed all beaches to swimmers in the afternoon, but they later reopened, CBS2's Jenna DeAngelis reported.
In a briefing, Town Supervisor Don Clavin said the shutdown was a safety precaution they had to take after multiple sharks were spotted along the shoreline.
"We've put out additional lifeguards on the coastline. We also have our Jet Ski shark patrol going up and down the coast," Clavin said.
"All of a sudden, they just had everybody come out of the water," said Tracy Fowler, who was visiting from South Carolina.
"They whistled and there was a lifeguard out on a surfboard, they called him in, so we were like, uh-oh," Merrick resident Sue Tice said.
Shark patrol teams were out on the water to monitor the situation. Swimming was suspended for about two hours.
It started around 1 p.m. when lifeguards said they saw a shark about 20 yards from the shore. Another was spotted jumping out of the water.
Around 6:30 p.m., there was another shark sighting at Jones Beach by a state police helicopter.
This followed several shark sightings at Jones Beach on Tuesday. A lifeguard was bitten by what was suspected to be a shark the day before.
An abundance of bait and bunker fish are likely attracting the sharks, as seen in video captured Saturday off Southampton by Christopher Paparo, Manager of Marine Sciences Center at Stonybrook University Southampton and member of the South Fork Natural History Museum's Shark Research team.
"The one thing about sharks is without sharks our whole ecosystem collapses, sharks are a sign of a healthy ecosystem," he said. "Seeing the sharks here is a sign that our waters are getting better."
Paparo researches and studies sharks with a team using satellite tags.
"It gives us a really good idea of how these sharks utilize our waters," he said.
In the waters at Lido Beach, lifeguards believe they saw two blacktip reef sharks.
"We have a very intense education process, and by that, they're able to identify the sharks," said Justine Anderson, head lifeguard at Point Lookout/Lido Beach.
"These are really unique sharks. They're more of a Caribbean shark. They're known to come close to the shoreline in feeding areas, so the concern is obviously with swimmers," Clavin said.
Paparo says they could also be the nearly identical spinner shark.
"They look almost identical they both have black tips on their fins, the only difference is the black tip shark does not have a black tip on its anal fin," he said explaining its hard to differentiate the two without taking it out of the water. "But both of them, they act, the same they feed the same, they jump out of the water."
Regardless, these sightings, to him, are no surprise.
"What's happening is as climate changes, oceans are warming, populations are shifting north," he said. "People don't realize how many species of sharks are found here on Long Island."
Paparo says, however, you mostly likely don't need to worry too much.
"Realistically in the world there's about 80 to 100 attacks worldwide each year. There's a better chance you're going to get into a serious accident on the way to the beach than probably even ever seeing a shark," he said.
Even so, he offered some advice.
"If there's a large school of baitfish like bunker in the water, probably not a wise idea to go swimming. It's not that they're going to try to eat you, but in a confusion frenzy of trying to grab little bait fish, they might not see you and then accidentally bump you or bite you," he said.
The town supervisor said most sightings last year were in August, so this year, it's a bit sooner. Either way, you can expect to see more patrols to help keep beachgoers safe.
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