The six whales washed up between May 21 and 28. The first, a yearling gray whale, washed up in Bolinas, in Marin County, on May 21. A partial necropsy that was conducted May 23 was inconclusive and the whale’s cause of death remains unknown, CalAcademy said.

Five more gray whales were found dead in the San Francisco Bay Area within the past week, bringing this year's total number of whale deaths up to 14.