A necropsy on a stranded blue whale indicates that the creature died from blunt force trauma due to a boat strike, the Marine Mammal Center said Saturday.The 79-foot blue whale was found beached on Agate Beach in Bolinas. Scientists with the Marine Mammal Center identified the blue whale as an adult female. This particular whale was first spotted in 1999 and has been seen about a dozen times, mostly near the Santa Barbara Channel, according to the Center. A team of scientists from the Marine Mammal Center and the California Academy of Sciences came to the beach to take initial measurements and tissue samples Friday, the Marine Mammal Center said. The whale's body is mostly intact. Researchers say it's rare to find a carcass in such good condition and that could help them learn more about the species. Blue whales are the largest animal on earth and have a distinct blue-gray coloration, the Center said. About 2,800 live off the California coast. -- Associated Press contributed to this report.