LONG ISLAND, N.Y. (PIX11) — A man was recovering Friday night after a possible run-in with a shark.

Jones Beach lifeguards and Nassau County police who rushed to the scene never found a shark, but medical personnel said the man’s injury did look like a bite.

Authorities told PIX11 News the 37-year-old victim was swimming in the ocean when something cut his right foot.

With tens of thousands of people expected to be swimming at beaches, officials said they’re on high alert. Lifeguards are scanning the water for potential dangers.

Typically, officials said sharks don’t swim around Jones Beach. And even if there was one in the water, beachgoers would have a hard time noticing it. That’s why people have to be wary of purple flags they see at the beach.

“When the purple flag is up, that means there is some kind of marine danger,” one official said. “You should not go in the water.”