The sharks spotted off Westhampton appear to be relatively harmless, according to a marine expert, but a stretch of beach near where they were sighted will be off-limits until the weekend as a precaution, Suffolk officials said Wednesday.
Chris Paparo, senior aquarist at Atlantis Marine World in Riverhead, said pictures he had seen led him to believe they were basking sharks, adding that they typically appear off Long Island as summer approaches.
"Right on cue. Right at this time of year they show up," he said.
Beach staff and park police are monitoring the waters after sharks were seen Tuesday and Wednesday swimming off Cupsogue, said Tracey Bellone, deputy commissioner for the County Department of Parks, Recreation and Conservation.
She said up to five shark fins were spotted Wednesday between the bathing area and the Moriches Inlet at Cupsogue at about 10 a.m., but that she had personally seen only three.
She said a department employee estimated that one of the sharks was 16 to 20 feet in length, and two were smaller.
Basking sharks are a large, plankton-feeding species, and generally are harmless to humans, but they have turned up off Long Island before.
No sharks have been sighted at Smith Point, which staff is monitoring because it's next to Cupsogue, Bellone said.
"In all the years, I've never seen sharks on this coast," she said. "They are gigantic."
The beach will be closed to swimmers until officials feel comfortable, said Capt. Gary Henke of the Suffolk County Park Police. "We're going to err on the side of caution."
Signs warning of sharks are posted at both beaches, and park police and staff are also patrolling, Bellone said. Staff at the entrances to both parks are "letting people know of recent shark activity," she said.
Lifeguards do not begin monitoring weekday swimming at the beaches until June 24, Bellone said. Until then, people may swim only on weekends -- with lifeguards -- from 10 a.m. to 6 p.m.
"We'll continue to monitor the beaches 'til this weekend, when the lifeguards come on duty," Bellone said. "Then, on Saturday and Sunday, if there are any sightings, they'll clear the beaches."
With Gary Dymski
BASKING SHARK: A COUPLE OF FACTSName: So called because of its habit of sunning itself at the surface
Size: Usually about 25 feet in length, but up to 40 feet
Range: Found throughout Arctic and temperate waters. Typically seen in summers when it swims slowly through offshore waters, its mouth open to collect foodStatus: Heavily overfished, it is now a protected species in the United States