Paramedics took the boy to a local hospital for a bite on his thigh. He said he was on his surfboard when he was bitten, according to authorities. The boy swam out of the water and to his parents, authorities said.
The beach remained open as of 4 p.m. but swimming was not allowed, Ocean Rescue said.
This would be the second shark bite on the Treasure Coast in as many weeks. A German tourist was seriously injured last week in Vero Beach when a shark attack her thigh, officials there said.
It would also be the second shark attack in Jensen in three months. Frank Wacha, 61, said a bull shark chomped on his arm in March. Friday's attack happened in the same beach area as Wacha's bite.
This story will be updated with more information when it becomes available.
Staff writer Lamaur Stancil contributed to this report.