Four dead gray whales have washed ashore San Francisco Bay Area beaches in the last nine days, with experts saying Friday one was struck by a ship. They were trying to determine how the other three died. "It’s alarming to respond to four dead gray whales in just over a week because it really puts into perspective the current challenges faced by this species," says Dr. Pádraig Duignan, Director of Pathology at The Marine Mammal Center. The carcass of a 41-foot adult female gray whale landed at San Francisco’s Crissy Field on March 31. A second adult female was found last Saturday in Moss Beach in San Mateo County. A third was found Wednesday floating near the Berkeley Marina and the following day one washed up in Marin County's Muir Beach. More from the AP: