WELLFLEET, MASS. -- Cape Cod officials are reminding visitors ahead of the July Fourth holiday that the famous Massachusetts tourist destination remains a popular gathering spot for great white sharks.

Cape Cod National Seashore Chief Ranger Leslie Reynolds warns that sharks are coming close enough to shore to be a concern for swimmers.

Local officials say they've documented at least two shark attacks on seals in recent days. Gregory Skomal, a prominent local shark researcher, tagged three great whites earlier this month.

Local residents concerned about the booming shark population say they'll boost their efforts to help protect swimmers this summer using spotter planes.