Head of the Meadow beach in Truro was closed to swimmers Friday after a shark was spotted chasing a seal just 10 feet away from the shore, according to the Cape Cod National Seashore.

The hungry fish was seen around 11 a.m. The water was closed to swimmers for one hour, seashore officials said in the Sharktivity app.

The beach was reopened to swimmers around 12 p.m., said CCNS Chief Ranger Leslie Reynolds.

Katie Camero can be reached at katie.camero@globe.com. Follow her on Twitter @camerokt