Swimmers beware, great white sharks are lurking in waters close to Cape Cod beaches. 

Recent sightings reported by the Sharktivity app have included a shark 100 feet off Chatham's North Beach Island, 59 yards off Nauset Outer Beach in Orleans and 50 yards off Nauset Beach, also in Orleans. 

According to experts the number of sharks in local waters is expected to increase as the seal population grows.