Dead 44-Foot Gray Whale Likely Collided With Ship

A massive gray whale that was found near the Bay Bridge in San Francisco was likely killed by blunt force trauma from a ship, according to necropsy results from the Marine Mammal Center in California.

With the help of the California Academy of Sciences the MMC performed a necropsy of the 44-foot-long female gray whale on Wednesday. The necropsy found that the whale had "significant bruising and hemorrhaging to blubber and muscle tissue" on one side of its body. The whale also had fractures and contusions that further suggested blunt force trauma, according to a release from the MMC.

While examining the whale, researchers found "a very significant fracture along the cranium," Pádraig Duignan, the chief research pathologist at the MMC, told Newsweek. "It would be like a massive concussion, and she probably lost consciousness right away," Duignan said about the whale.

"One of the challenges with whales, as opposed to other animals, is that they decompose rapidly," said Duignan. But the researchers were able to identify the likely cause of death in this particular whale about halfway through the examination, Barbie Halaska, a research assistant at MMC told Newsweek.

The Coast Guard alerted the MMC to the whale that was seen floating below the Bay Bridge on Friday. The whale ended up stuck on rocks near Oakland Airport over the weekend and the MMC towed it Tuesday before the necropsy was performed Wednesday, Halaska said. The whale is the third to die in the area since early March.

On March 9, a male gray whale was found on Angel Island, in the San Franciso Bay, and the MMC reported that the minimal contents in the whale's stomach suggest it died from "severe malnutrition." Less than a month later on April 3, another whale was discovered. The MMC tweeted that the mammal "showed severe entanglement and orca trauma," that were likely contributors to its death.

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A 44-foot adult female gray whale carcass decomposes on Sandy Springs Beach at Angel Island State Park, in San Francisco Bay. After a complete autopsy, scientists concluded the injuries sustained by the whale are consistent with a vessel collision. © The Marine Mammal Center

Gray whales are currently making their migration from the Baja area of California up to the colder regions along the northern West Coast and the Arctic. The migration usually begins in March and continues until the end of May, which puts whales on track to be passing the Bay Area right around this time of the month.

Some whales even stop for part of their migration in Northern California near the Redwood National and State Parks, and some stay in the area for the summer, according to the National Park Service.

This female whale may have been feeding on the bottom of the shallow bay and surfaced into a ship. "The volume of ship traffic is really high," said Duignan. While all three of the whales died in a similar area, they all died of different causes and their deaths are not linked.

As for this whale, its body will stay on the beach on Angel Island where it will it will decompose. "We can let it decompose naturally," Halaska said. "It's basically an area where nature can be allowed to take its course."