Necropsy: Whale at Ocean Beach died from ship strike

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Scientists at The Marine Mammal Center confirm the gray whale that stranded at Ocean Beach in San Francisco died from blunt force trauma that can be attributed to a ship strike

A necropsy was performed Tuesday on a gray whale that washed ashore at Ocean Beach in San Francisco, bringing the total this year to nine in the Bay Area -- the highest number seen in the last two decades, scientists said.

“We’re incredibly concerned to discover the death of four gray whales due to ship strikes already this year, along with deaths attributed to malnutrition,” sayid Dr. Padraig Duignan, Chief Research Pathologist at The Marine Mammal Center. “While this is a tragic discovery, the information gathered from these whales is shared directly with our partners, helping inform policy decisions that can protect habitat areas, change shipping lane speeds that intersect migration routes and better understand shifting food sources for marine mammals.”

During the necropsy, scientists discovered multiple fractures to the animal’s skull and upper vertebrae with significant bruising and hemorrhaging in the surrounding area consistent with blunt force trauma as a result of a ship strike. The Center’s scientists identified the gray whale as a 41-foot adult female that was in the early stages of decomposition based on the quality of the skin condition and internal tissues. The team also noted that the whale was in poor body condition with a thinner than usual blubber layer. 

So far, the center has completed necropsies on nine gray whales in 2019. Three of those whales died because of ship strikes and four died of malnutrition. The cause of death for the eighth whale in Point Reyes National Seashore has not yet been determined. Blunt-force trauma from ship strikes, malnutrition and entanglements are the most common causes of death in whales according to the Marine Mammal Center.

The "anomalous oceanographic conditions" are a result of warming oceanic conditions, which have contributed to shifting food sources, according to The Marine Mammal Center.

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What's also happening this year is that there are more gray whales in the San Francisco Bay than usual, he said, as the population continues their northerly migration this spring. Why that is still hasn't been determined.

Several onlookers came to watch scientists take pictures and examine the massive mammal.

Myla Jung brought her children to witness science in action.

"To see it in person," she said, noting the krill, the barnacles and the sheer size of the whale, "is amazing."

Others were saddened.

"It's so emotional to me," said Jackie Mitchell. "So emotional. I went whale watching once and only saw a small killer whale. And so my goal this year was to see a big one. But I didn't want to see it like this.