At a beach in the Bay Area, local researchers theorize that a gray whale found deceased this month had been hit multiple times, including at least once by a ship.
The 39-foot male gray whale, according to scientists from the Marine Mammal Center in Sausalito, the California Academy of Sciences in San Francisco, and the National Park Service, likely suffered a ship strike to its back while in the San Francisco Bay. This unfortunate incident, they believe, led to malnourishment and a gradual decline in the whale’s health.
A lengthy scar on the whale’s back was first noticed sometime in February. Following this, the Marine Mammal Center noted the whale’s deteriorating condition over a record-breaking 75 days of observations. After performing a necropsy, the researchers deduced that the whale had been struck on the head just before its demise.
On May 7, the whale’s lifeless body washed up on North Beach in Point Reyes, just a day after another dead gray whale was discovered on the northern tip of Agate Beach in the same area. The 37-foot adult male didn’t display any signs of trauma, which led scientists to assume his death was abrupt.
Addressing the back-to-back discoveries of two gray whales, including one that had been under active monitoring in the San Francisco Bay, Dr. Pádraig Duignan, director of pathology at the Marine Mammal Center, expressed that it was both demanding and worrisome.
This year, these two whales are the third and fourth to be found deceased along the Bay Area coastlines. Except for the whale located on Agate Beach, vessel strikes are suspected to have caused the death of each whale.
The National Oceanic and Atmospheric Administration has identified an unusual mortality event among West Coast gray whales since early 2019. While the federal agency noted that many of these whales exhibited signs of emaciation, these findings haven’t been consistent across all the examined whales.
By the end of 2022, the bodies of 81 whales had washed up on the beaches of California.
Duignan noted that gray whales, as indicators of ocean health, are subject to several anthropogenic threats, including vessel strikes. He emphasized, “This crucial observation and pathology data can help make a more compelling argument about the current challenges faced by this species and possible solutions to address them.”