PACIFICA, Calif. (AP/CBS13) — A 12th dead whale has now washed up on a San Francisco Bay Area beach this year, authorities said.

The carcass of a gray whale was discovered on Pacifica State Beach on Friday.

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Tissue samples collected on Saturday confirmed it was an approximately 47-foot (14-meter) adult male, said Giancarlo Rulli, a spokesman for The Marine Mammal Center. He said because the whale was in an advanced state of decomposition, scientists decided not to perform a necropsy to determine how it died.

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Ten gray whales, one pygmy sperm whale and one fin whale have been reported dead on San Francisco Bay Area shores since the start of 2021, according to the California Academy of Sciences. Necropsies revealed that two died of a ship strike and two others were suspected to have died of ship strikes. Eight of the deaths were from undetermined causes.

Since 2019, the U.S. National Oceanic and Atmospheric Administration has been investigating what it terms an unusual mortality event because of a higher rate of emaciated or injured gray whales stranded on beaches across the West Coast.

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Malnutrition, entanglement and trauma from ship strikes have been the most common causes of whale deaths in the Bay Area in recent years, according to the Mammal Center.