Davis Park Beach at the eastern end of Fire Island National Seashore in Patchogue was closed to the public until further notice due to shark sightings, according to a notice posted on the Town of Brookhaven's website Monday.
The sightings would be furthest east a shark has been seen on Long Island this summer.
Town officials did not immediately respond to a request for comment.
In recent weeks, several species of sharks have been spotted off Atlantic beaches, including Jones Beach State Park, Babylon's Robert Moses State Park and at Point Lookout in the Town of Hempstead, prompting officials to halt swimming.
Drones, water scooters, helicopters and surf and police boats have all been deployed to find the predators.
This summer, similar to 2020, more sharks are raising alarms as they swim closer to shore — possibly, scientists say, chasing bait fish.
Shark sightings are becoming more routine, as Long Island's waters revive from decades of pollution, though both the Great South Bay and Long Island Sound still have areas where oxygen levels have been sorely depleted, scientists say.
Scientists say the Atlantic Ocean is cleaner, so both the bait fish and the sharks that feed on them are more likely to be seen than just a generation ago. Improved wastewater treatment plants are the main reason the water quality has improved, environmental groups say.