SAN FRANCISCO – A gray whale found floating off the coast of Alameda on April 20 likely died because of this of blunt force injuries from a ship impact, in line with an autopsy.
The death was the primary “local whale mortality” of the 12 months, the California Academy of Sciences said in a press release on Tuesday.
Scientists from the academy and the Marine Mammal Center conducted the autopsy Saturday. According to the academy, the whale was identified as a 40-foot adult female with “full stomach contents and injuries consistent with blunt force trauma.”
The academy said the official explanation for death couldn’t be fully confirmed on account of the whale's decomposed condition and posture.
The whale was first spotted on April 20 near the Robert W. Crown Memorial State Beach in Alameda. The next morning, it landed barely offshore in a sandbar or mud deposit before breaking away and floating freely with the tide, the academy said.
On April 22, the whale was towed to a protected location on Angel Island.
The academy said extreme wind conditions and the timing of the tides delayed the autopsy by several days.
According to the academy, the variety of gray whale strandings tends to extend between March and May, when the whales pass the Bay Area on their method to Alaska.
The academy said the whale's death occurred shortly after the National Oceanic and Atmospheric Administration (NOAA) ended an unusual mortality event (UME) involving North Pacific gray whales on the west coast of North America.
According to the academy, the UME was first declared in 2019 after changes within the whale's feeding grounds led to the whales dying off.
The academy said NOAA estimates the grey whale population declined from 20,500 whales in 2019 to 14,526 whales in 2023. Malnutrition, killer whale hunting, entanglements and ship strikes were listed as probably the most common causes of death.
“We continue to document ship strike injuries in gray whales in San Francisco Bay, regardless of other threats to the animals,” said Denise Greig, a research scientist on the academy. “We hope the information we collect can help make the bay safer for whales, ships and people.”
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