Endangered male fin whale’s cause of death: ‘vessel collision’

A file photo of a fin whale. The dead whale found floating beside an Alameda dock this week was a young, 52-foot male fin whale. The species is the second largest animal after the blue whale. A file photo of a fin whale. The dead whale found floating beside an Alameda dock this week was a young, 52-foot male fin whale. The species is the second largest animal after the blue whale. Photo: Mark Jones Roving Tortoise Photos, Getty Images Photo: Mark Jones Roving Tortoise Photos, Getty Images Image 1 of / 4 Caption Close Endangered male fin whale’s cause of death: ‘vessel collision’ 1 / 4 Back to Gallery

The dead whale found floating beside an Alameda dock this week was identified Friday as a young, 52-foot male fin whale.

Photo: Dead whale washes up in estuary across from Jack London Square in Oakland. @TMMC is investigating. pic.twitter.com/swyeshTaS0 — NBC Bay Area (@nbcbayarea) August 26, 2015

The species is the second-largest animal after the blue whale, living primarily in the northern Pacific Ocean. It’s considered endangered and isn’t commonly sighted within the confines of San Francisco Bay.

The juvenile in the Oakland Estuary was apparently dragged there this week from the open seas by a container ship. Based on the necropsy, the whale was killed by blunt force trauma from a ship. The official cause of death is “vessel collision,” according to the Marine Mammal Center.

The whale had a fractured and dislocated vertebrae, fractured and dislocated ribs, as well as hemorrhaging, which indicated the whale was alive when it was hit.

“Every whale stranding is an important opportunity to learn more about these creatures, and how we can prevent future deaths,” said Frances Gulland, senior scientist at the center. “With an increase in worldwide shipping, deaths from ship strikes will become more and more of a problem. Locally we must identify a solution that both works for shipping companies and keeps whales safe.”

At least four dead fin whales have washed up on California beaches in recent years, according to the center. The latest was a 42-foot juvenile found on Stinson Beach in August 2013.

The whales typically live up to 90 years and grow to 85 feet long and 75 tons.

This week’s carcass was towed out of the Oakland Estuary, where it was obstructing a shipping lane, and taken to Angel Island for a necropsy.

Kurtis Alexander is a San Francisco Chronicle staff writer. E-mail: kalexander@sfchronicle.com Twitter: @kurtisalexander