Blame it on "Shark Week."
Beachgoers along some parts of Nassau County's South Shore reported shark sightings this week, prompting lifeguards at Long Beach and other nearby areas to briefly close beaches to swimmers.
Those sharks were, in fact, cownose rays that were mating, lifeguards said Friday.
Lifeguards speculated that the Discovery Channel's "Shark Week" series was responsible for the heightened awareness of the fearsome finned ones. The popular annual series highlights everything from how to fend off shark attacks to a big-air competition between different species of sharks.
Lifeguard Vinny Leis, 32, a 14-year veteran at Long Beach, was sent on a water scooter to investigate the sightings Thursday.
"There were maybe two dozen stingrays along a two-mile stretch of beach, and at least 200 yards offshore," he said. "They were swimming with one fin out of the water, so I get why people were confused."
Leis said that before he went out to investigate, beachgoers and fellow lifeguards who have tuned in to the series lectured him on the dangers of the bull shark.
"I guess everyone is a marine biologist this week," Leis said with a laugh.
The shark-sighting reports, which came from patrons along a half-dozen beaches, were the first all year, Long Beach assistant chief of lifeguards George Schilling said, tying the phenomenon to "Shark Week."
"We closed the beach for about 10 minutes to investigate the sightings and reopened immediately after we determined there was no danger," Schilling said.
The rays usually show up every year in early August and in the past have swum in close to shore, Schilling said.
"A few years ago they were swimming in knee-deep water," he said. "We closed the beach then."
Similar sightings were made off the beaches at Hempstead Town's Town Park at Malibu and the Nickerson Beach campground, according to spokeswoman Susie Pokalsky.
The false alarm did not prevent rumors of shark sightings from spreading even after Leis determined the fish were really rays.
Janet Nash, the mother of one of the lifeguards, said she even heard people talking about sharks while at her job at NYU Medical Center in Manhattan.
"It must be 'Shark Week,' " she said before heading into the water for a swim.