Updated

Nine beaches on Nantucket have been closed to swimming after testing found high levels of bacteria.

The island’s health director suspects that a sampling error may be responsible for the results and additional testing will be conducted on Monday.

The nine beaches are Miacomet Pond; Dionis Beach; Washing Pond Beach; Jettes Beach; Children's Beach; Washington Street Beach; 40th Pole; Wauwinet Harbor Side Beach; and Wauwinet Ocean Side Beach.

The beaches are not scheduled to officially open for the summer season until next week. There are more than 20 public beaches on the Massachusetts island.

The health department says on average there are only about three beach closures per year on the island due to high bacteria levels.