This flag will fly at Nickerson Beach if sharks are near

Nassau rolled out a new warning system Monday to alert beachgoers when it’s safe to go back in the water following a shark sighting.

The announcement came hours after Smith Point County Beach in Shirley was closed to swimming Monday after lifeguards spotted several sharks less than 20 yards from the shoreline.

In Nassau, South Shore beach closures have become all too common this summer, where there have been 26 shark sightings this summer — including two more Monday at Jones Beach — as compared to 20 sightings all last summer, said County Executive Laura Curran.

At a news conference at county-run Nickerson Beach, Curran unveiled a purple flag with a white shark silhouette that she said will hang at the beach's entrance if a shark has been spotted in the previous 24 hours. Swimming will be restricted for one hour in the area as lifeguards on jet skis and aerial patrols confirm there are no sharks nearby.

The flag system, Curran said, is in use at beaches throughout New England, including Massachusetts and Maine.

"This appears to be our new normal," Curran said. "We want people to know if they’re coming to the beach, if they can go into the water or not and this is a clear and easy way to let them know."

Sharks have been attracted to Long Island by warmer waters, a growing presence of gray seals and by large schools of bait fish that have come up the coast.

"Sharks are on the increase and it's all because of the ecosystem where the waters are getting better," said Capt. Tom Paladino, who operates a sightseeing boat out of Brooklyn.

Most of the sharks spotted in Nassau this summer have been sand tiger sharks and threshers, which are not known to attack humans. However, a Jones Beach lifeguard reported a possible one-inch shark bite last month after he noticed his leg was cut and saw a possible sand tiger shark nearby .

Officials last year spotted larger more aggressive predators like bull sharks close to shore.

At Smith Point, multiple five- to six-foot sharks were spotted by lifeguards Monday morning near the shoreline, forcing the closure of the beach, said Suffolk County Executive Steve Bellone. It was the second time this summer that Smith Point, located on the east end of Fire Island, was closed due to shark sightings. Before this summer, there were no closures there due to shark sightings, officials said. The beach, which was previously closed to swimmers on Aug. 2 after a shark sighting, reopened at 3 p.m. Monday.

Suffolk lifeguards actively patrol for sharks on paddle boards, surfboards and jet skis, while also monitoring from the shore.

"This is not a common occurrence," Bellone said. "Our lifeguards are on alert. They are watching very closely."

Bellone urged beachgoers to swim in groups, to not wander too far off shore, to swim only when lifeguards are on duty and to take off shiny jewelry before going into the water.

Shark bites off Long Island are extremely rare. Since 1837, officials said, there have only been about a dozen shark attacks off the beaches of Long Island and the rest of the metropolitan area.

With Howard Schnapp and James Carbone

By Robert Brodsky

robert.brodsky@newsday.com,john.asbury@newsday.com@BrodskyRobert,

Robert Brodsky is a breaking news reporter who has worked at Newsday since 2011. He is a Queens College and American University alum.