A 16-year-old boy says he was bitten by a shark while swimming at Delaware's Cape Henlopen State Park.
The shark attack happened around 5:00 p.m. Monday.
The teenager, Andrew Vance of Delmar, was wading in 5 feet of water when the shark bit his arm.
He reported that the shark released its bite and swam away after he batted it with his right arm.
"I believe it was a juvenile sandbar shark. The sandbar sharks are in the area right now having their young. There are a good many of the young ones out there right now," Scott Newlyn of the Delaware Division of Fish and Wildlife said.
Officials say sandbar sharks are very common in these waters, especially this time of years because they are having their pups, but attacks are extremely rare.
"I've been talking to staff who've been here for 15 to 20 years, they can't remember the last time there was one of the these," Collin O'Mara, Secretary of Natural Resources and Environmental Control, said.
State officials say the reported shark bite led them to delay Tuesday's opening of swimming areas at the park.
The beach was reopened just after 1:00 p.m.
The Associated Press contributed to this report