Dead blue whale washes ashore at Daly City beach

A dead blue whale floated in the bay Wednesday before washing ashore at Thornton State Beach in Daly City. A dead blue whale floated in the bay Wednesday before washing ashore at Thornton State Beach in Daly City. Photo: KTVU Photo: KTVU Image 1 of / 10 Caption Close Dead blue whale washes ashore at Daly City beach 1 / 10 Back to Gallery

A dead male blue whale — the largest animal in the world — washed ashore Wednesday at Thornton State Beach in Daly City.

Veterinarians with the Marine Mammal Center and California Academy of Sciences will go to the beach Thursday to conduct a necropsy, collect tissues and bones, and try to determine what caused the whale to die.

The center was alerted to the whale, floating roughly a quarter mile from the shore, about noon Wednesday. By the time it washed ashore there was little sunlight left for the examination.

Visible, prolapsed genitalia made it clear the whale was male, said Giancarlo Rulli, a spokesman for the mammal center.

The creature was the seventh blue whale carcass beached in the last 40 years along the Central and Northern California coastline, Rulli said.

The last dead blue whale to wash ashore in the region was in 2010 at the Bean Hollow State Beach in San Mateo County. That female whale, which had been carrying a fetus, died of blunt force trauma after being hit by a ship, the veterinarians determined.

Rulli advised beachgoers to stay clear of the carcass.

Blue whales can grow larger than the length of an NBA basketball court and weigh more than 15 school buses.

Whales often migrate to the Central California coast in autumn for feeding, Rulli said.

Kimberly Veklerov is a San Francisco Chronicle staff writer. Email: kveklerov@sfchronicle.com Twitter: @kveklerov