DALY CITY (KRON/BCN) — A dead blue whale that washed ashore Wednesday on the Daly City coast will be left to decompose, a spokesman for the Marine Mammal Center said Friday.

Marine Mammal Center officials said on Friday the whale collided with a vessel.

Scientists said there were necrotic tissue areas near the fractured skull and extensive contusions that extended along the spine of the carcass.

“Blue whales can move very fast through the water column, so studying both the fractures, tissue, and internal fluids can help paint a clearer picture of the condition of this animal prior to sustaining the trauma,” Marine Mammal Center Chief Pathologist Padraig Duignan said.

The whale was spotted at about 12:30 p.m. Wednesday roughly a quarter-mile from the Daly City shoreline. It drifted closer to shore as the day went on, center spokesman Giancarlo Rulli said.

Scientists completed a full necropsy Thursday. Marine Mammal Center scientists took tissue and blubber samples and scientists with the California Academy of Sciences took a pelvic bone, Rulli said.

The academy already has a pretty extensive whale bone collection, he said.

“We are leaving the carcass to naturally decompose,” Rulli said.

The 65-foot sub-adult carcass is on a beach below a sheer cliff and not near a residential area so the smell of the decomposing carcass is likely to affect few people.

Blue whales are the largest animal on earth and an endangered species. The necropsy will give scientists solid baseline information to share with other scientists.

The whale was already pretty much decomposed when it got to shore, Rulli said.

Scientists were able to discover that the back of the whale’s skull was fractured in multiple places and the surrounding tissue had massive hemorrhaging.

Rulli could not say how the whale died.

The injuries are consistent with blunt force trauma, but he said the whale could have been struck after it died from lack of food or some other cause.