While the gray whale population may be rebounding, this is also having the side effect of more of them turning up dead in the waters of the San Francisco Bay, as the 21 dead whales found dead here this year are the most in 25 years.

There have been encouraging signs in recent years that the West Coast gray whale population was rebounding in numbers. And this may correlate with the troubling trend of more of these creatures being found dead in the San Francisco Bay waters, as during just one week this past May, five gray whales were found dead, in what may have all been separate, unrelated incidents.

KPIX has the news that yet another 37-foot, female subadult whale was found dead in mid-July near the Richmond-San Rafael Bridge, likely killed when hit by a vessel. But the more troubling aspect to that report is that 2025 has been the deadliest year in 25 years for gray whales in the San Francisco Bay, as this whale’s death marked the 21st gray whale death in the bay this year.

"This latest gray whale caught everyone a bit by surprise given how late in the season it is and the fact that we had not sighted the species in the Bay in nearly two weeks," Marin County’s Marine Mammal Center director of cetacean conservation biology Kathi George told KPIX.

The large number of gray whale deaths may just be a consequence of there having been what biologists describe as an "unusually high number" of whales entering the San Francisco Bay this year. There were 35 confirmed gray whale sightings in the SF Bay this year, compared to only four in the entire year of 2024.

But with 35 confirmed sightings, 21 dead seems like a much higher number than it ought to be. And biologists believe boat collisions are the problem, encouraging even the smallest boats to exercise caution in the bay.  

"With the bay and our immediate coast serving as a shared space for commerce and increasing whale activity, including humpback whales, it's vital that all boaters, from large commercial vessels to sailboats, be whale aware,” George added to KTVU. “If you see a blow, go slow.”

Related: Five More Dead Gray Whales Bring Bay Area Death Toll to 14 [SFist]

Image: @LACoLifeguards via Twitter