Smith Point and Cupsogue Beach suspended swimming Sunday after the lifeguard was bitten during a training exercise.
"While shark attacks off Long Island Shores are extremely rare, officials will provide an update on the situation and outline additional measures residents can take to remain safe in the water," County Executive Steve Bellone's office said in a statement.
The lifeguard, identified as Zach Gallo, had been playing the role of a victim during a training exercise when the shark bit him in the chest and hand, Bellone told an afternoon news conference.
The attack happened about 10:15 a.m. at Smith Point Beach in Shirley. The lifeguard received stitches and was in "very good spirits," Bellone said.
"If you're going to have an encounter with a shark this is probably the best scenario you could have," Bellone said, adding the lifeguard received immediate treatment from other officials already engaged in the training. "We have never had an incident like this occur. Hopefully, we never will again."
Bellone said there was an additional shark sighting following the attack, though it was not clear whether it was the same shark.
The beach was closed to swimming for the rest of the day but is expected to reopen Monday with officials monitoring the water for sharks.
Last week, police in Nassau County investigated a possible shark attack after a 37-year-old man who was swimming in the waters off of Wantagh sustained a laceration on his right foot.
Shark sightings at Long Island beaches are becoming a growing problem.
Warming ocean temperatures are believed to be helping draw sharks to the New York coastline. Wildlife experts say that new types of sharks could be spotted this year, including tropical hammerheads.
The state is expanding a drone program to track sharks this summer.
With the Associated Press.