Fifth Dead Whale Found in San Francisco Bay Waters

Marine biologists are investigating the death of a fifth whale discovered in the waters of the San Francisco Bay in less than three weeks [1]. The carcass was spotted Friday morning near the Golden Gate Bridge in Sausalito by an employee at the Bay Area Discovery Museum [1].

Key takeaways

• This is the fifth whale death reported in the region since March 17 [1].
• Analysis of two of the deceased whales has revealed injuries consistent with marine vessel collisions [1].
• Experts from the California Academy of Sciences and the Marine Mammal Center are conducting autopsies and collecting samples to determine the causes of death [1].
• Scientists have noted an "unusually high" number of gray whale sightings in the area this year, with more than 30 individuals confirmed [2].
• Federal law requires the public to maintain a distance of at least 100 meters from live whales [1].

Investigation into rising whale fatalities

The recent discovery follows a series of whale deaths that began in mid-March, with additional sightings reported on March 25, March 28, and over the weekend [1]. While the cause of death for the latest whale remains under investigation, experts believe it had been seen alive in the bay prior to its death [1]. The California Academy of Sciences is leading the response, with teams already working on autopsies for other whales found in the area [1].

Researchers are working to understand why so many whales have appeared in the bay this year, a trend that has surprised experts given the late timing in the season [2]. While vessel strikes have been confirmed as the cause of death for several of the whales, the reasons for other fatalities remain uncertain [2]. Common factors in recent years for whale deaths in the region have included malnutrition, entanglement in fishing gear, and trauma from ship strikes [3].

Why it matters

The spike in fatalities occurs as gray whale populations in the North Pacific continue to recover from a significant "unusual mortality event" between 2019 and 2023, which saw the population drop by an estimated 45 percent [2]. Scientists are concerned that climate change is altering ocean conditions and reducing the availability of prey in the Arctic, further challenging the species [2].

To assist in ongoing research and safety efforts, experts are urging the public to report sightings of injured or dead whales to the Marine Mammal Center hotline at 415-289-7325 [1]. Additionally, the National Oceanic and Atmospheric Administration (NOAA) promotes the use of the "Whale Alert" app, which helps maritime vessels avoid strikes and allows researchers to track the locations of marine mammals [1].