A total of 15 whales, including 14 gray whales and one minke whale, have died so far in 2025, according to a joint press release from California Academy of Sciences and the Marine Mammal Center.

“The reason or potential reasons behind the massive spike in sightings this year are still being investigated by researchers,” the release said.

The latest death, a gray whale found in the San Francisco Bay Area on Wednesday, marked the sixth whale death in as many days.

Newsweek reached out via email to the California Academy of Sciences and the Marine Mammal Center on Saturday during non-working hours for more information.

Why It Matters

There has been “unusually high number of sightings” of whales in the region this year but there has also been an increase in deaths. The whale population has seen a 45 percent decrease since the 2019- 2023 Unusual Mortality Event (UME), according to the release.

A record-low number of newborn whales was also seen this year, causing concern among researchers for the long-term outlook for the North Pacific gray whales, following the second UME in a 20-year period.

“These whales basically left the Arctic with a half tank,” Giancarlo Rulli, a spokesperson for the Marine Mammal Center in Sausalito, recently told Phys.org about the other deceased whales discovered in the region.

“The food sources that they were normally accustomed to eating that were highly nutritious for this massive, 10,000–12,000-mile journey, had moved farther away due to climate change, and as a result, these whales were left to forage on food matter that was much less nutritious.”

What To Know

The whale on Wednesday was found near the Alamere Falls in Point Reyes National Seashore, the joint release said, which is about 30 miles northwest of San Francisco.

While some of the deceased mammals have been necropsied, others have either been too far decomposed or stranded in areas that are inaccessible, making it difficult to pin these deaths on one similar cause.

While it is not unusual to see whales in the region as they migrate, the number of deaths is the highest it has been, including in 2019 when 14 whales were found deceased in the UME, according to the release.

The number of deaths currently matches the record of 15 for all of 2021, the release said. At least three of these deaths have been attributed to suspected vessel strikes, but others remain undetermined.

The whales that have been spotted alive have been observed to be either regular size or emaciated.

There are a total of 33 confirmed gray whale sightings in the San Francisco Bay this year, compared to only six seen last year, with about a third of those whales remaining in the bay for about 20 days.

Whale carcasses have been found as far north as Alamere Falls, as far west as Farallon Islands and as inland as Berkeley.

What People Are Saying

The California Academy of Sciences and partners at The Marine Mammal Center said in the press release: “With San Francisco Bay serving as a shared space for commerce and increased gray whale activity, experts at the Academy and the Center note it’s vital that all boaters—from large commercial vessels to sailboats—be ‘whale aware’ and continue to slow down. Gray whales often have a very low profile in the water that can make them difficult to sight, unlike other coastal whales like humpback whales.”

What Happens Next

The results of the necropsy on the whale found on Wednesday are still pending, complicated by a number of factors due to “inaccessible locations that hinder full post-mortem investigations, as well as poor tissue quality from advanced decomposition, and the lack of available locations to tow for further investigation.”

Meanwhile, the whales that are alive are expected to be in “the bay for another one to two weeks before continuing their annual northern migration to arctic feeding grounds,” according to the release.

If people do see whales, they can report them through an app called Whale Alert or the Marine Mammal Center website. Sightings of dead whales should be reported to the Academy’s department of Ornithology and Mammalogy.