Four dead gray whales washed ashore on San Francisco Bay area beaches in nine days, with experts announcing that two of the giant aquatic mammals died from ship strikes and an investigation is ongoing Saturday on the other two. Biologists with the non-profit Marine Mammal Center in California said in a release Saturday that two dead whales washed ashore in the Bay area on Thursday, joining two more that were discovered dead in area beaches since March 31. Of the four animals, two died from blunt force trauma from ship strikes, the center said. “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,” Padraig Duignan, director of pathology at the center said in a news release. Other common causes of gray whale deaths include starvation and complications from becoming entangled in deep …