Coastal waters from Mendocino to San Francisco Bay have become a graveyard for gray whales

MENDOCINO CO., 5/5/26 — The 40-foot male gray whale on RCA Beach had drifted past Tiburon on March 28, slid through the Golden Gate on a strong tide, and washed ashore in Bolinas the night of April 1. By the next afternoon, a team from the Marine Mammal Center and the California Academy of Sciences was on the sand in waders and elbow-length gloves, racing the next tide for samples — bone saws and meat hooks against the foul stench one writer compared to “a refrigerator left for weeks without power.”

They were looking for trauma.

Maggie Martinez, a veterinary pathologist who lacks a sense of smell, worked the gastrointestinal tract. “They tell us what and how much they are eating and if they’ve been exposed to any algal bloom toxins,” Martinez said. “I’m also grabbing a couple of tissues, like blubber and muscle, to try to look for trauma.”

Two weeks earlier, the same team had performed the same workup on the body of an adult female towed to a remote stretch of Angel Island; the Marine Mammal Center later classified that death as a suspected vessel strike. By Earth Day, at least nine gray whales had been found dead in Bay Area waters in 2026 — already on pace to challenge last year’s grim ledger of 24 dead whales, 21 of them grays, the highest tally in a quarter century.

Twelve days after the Bolinas necropsy, a paper landed in Frontiers in Marine Science that put the carcasses in context. Sonoma State graduate student Josephine Slaathaug and a team from the Marine Mammal Center and the California Academy of Sciences had spent the better part of a year matching photographs of living whales to photographs of dead ones. Their conclusion: at least 18% of the gray whales that have entered San Francisco Bay since 2018 have died there, and of those whose cause of death could be determined, more than 40% showed evidence of pre-mortem vessel trauma. Among the carcasses that received full internal necropsies, 60% bore the signature of a strike.

In fact, Slaathaug and her collaborators believe the real mortality rate is closer to half.”

Gray whales have a low profile to the water when they surface, and this makes them difficult to see in conditions like fog, which are common to San Francisco Bay,” Slaathaug explained in the study’s release. “Additionally, San Francisco Bay is a highly trafficked waterway, and the Golden Gate Strait serves as a bottleneck through which all traffic and whales must enter and exit.”

Co-author Bekah Lane, of the Center for Coastal Studies, was blunter. “In San Francisco Bay, the biggest threat to these whales is vessel traffic,” Lane said. “Route changes and speed restrictions have been found to significantly reduce vessel strike mortality to large whales.”

So why, with the science increasingly settled, are speed restrictions in the Bay and along the northern California coast still optional?

The science on speed

The science on vessel speed has been settled for almost two decades. A 2007 study in Marine Mammal Science established the dose-response curve every regulator now cites: at eight knots, a ship strike has about a one-in-six chance of killing a large whale; at fifteen, it is almost certain. Each additional knot of speed multiplies the odds of a fatal outcome roughly one and a half times.

In 2008, NOAA imposed mandatory 10-knot zones around North Atlantic right whale habitat on the East Coast. A follow-up analysis cut fatal-strike risk by 80 to 90 percent. The West Coast has no equivalent rule. California’s voluntary speed-reduction program, by the modeling of Cotton Rockwood at Point Blue Conservation Science, has cut blue and humpback strike deaths in the SF approaches by only 9 to 13 percent.

A voluntary fix for a mandatory problem

On Earth Day, April 22, California’s signature whale-protection program — Protecting Blue Whales and Blue Skies — formally expanded statewide under Assembly Bill 14, signed by Gov. Gavin Newsom last fall. The Vessel Speed Reduction zone, in which ships of 300 gross tons or larger are asked to travel at 10 knots or less, now extends along the entire California coastline and farther offshore — including, for the first time, the migration corridor off the Mendocino and Sonoma coasts, where the same gray whales transit twice a year past Bodega Head, Point Arena and Fort Bragg en route to and from the Arctic. The waters off Point Arena have produced their own gray whale strandings in recent years, including a carcass that washed up there in April 2020, cause undetermined.

“It’s a really big and positive step forward in maximizing whale protection in California,” said Jessica Morten, director of marine resource protection at the California Marine Sanctuary Foundation, who has worked on the program for a decade. The expansion, she said, was overdue: “We’ve implemented the program mostly near shore in recent years, and now we’re expanding to cover offshore habitat important to those migratory species.”

Cooperation has been climbing — 52 shipping companies enrolled for the 2026 season, up from 44 last year. But participation outside those zones is uneven, there are no penalties for opting out, and the bottleneck inside the Golden Gate, where Slaathaug’s whales are dying, sits largely outside the offshore VSR map.

The federal regulatory architecture for the SF approaches has been in legal limbo since 2022, when a federal court vacated NOAA’s biological opinion supporting the existing shipping lanes — finding the agency’s conclusion that the lanes posed no risk of “take” to whales and turtles “defies logic.” Three years later, the court-ordered replacement analysis still hadn’t materialized. In October 2025, the Center for Biological Diversity and Friends of the Earth sued NOAA and the Coast Guard a second time. That case is live in the Northern District of California.

What the Coast Guard already does — and what it can’t

In the meantime, the closest thing the Bay has to a real-time response runs out of the Coast Guard’s Vessel Traffic Service in San Francisco. When a whale is reported, VTS broadcasts the sighting to commercial mariners and asks them to slow down. When concentrations build along ferry routes, VTS coordinates with operators to reroute around them — most often east of Angel Island, last year’s hot spot.

“This year, gray whales have been migrating into the bay — whether it be for food or rest,” Gary Reed, the director of VTS San Francisco, told a newspaper. “When whales are reported, the Coast Guard broadcasts their location to commercial vessels and asks them to slow down. Ferries can be rerouted when concentrations of whales appear along their fixed transit routes, but container ships are confined to the deep-draft channel. Large ships are constrained by their draft. Unless we spend billions and billions of dollars on dredging different channels, they can’t deviate.”

That work happens with the existing VTS crew. There is no dedicated full-time staff for whale coordination, and the data flowing in is whatever a passing ship’s bridge officer or a shore-based biologist happens to phone in.

The Save Willy Act, introduced on Earth Day by Rep. Sam Liccardo, D-Campbell, with nine Bay Area cosponsors, would change that — funding a four-year pilot “Cetacean Desk” inside VTS San Francisco with up to two full-time positions, mandated to integrate real-time data from NOAA, the Coast Guard, state agencies, academic research groups, tribes, and the much larger fleet of commercial and recreational boats already on the water.

“Researchers track these whales daily, but we can scale their impact by crowdsourcing data from the many more numerous commercial and recreational boats, and building a centralized alert system,” Liccardo said in announcing the bill. “A whale desk will protect these magnificent creatures and help mariners avoid costly, harrowing collisions. Together, let’s Save Willy.”

Even the bill’s supporters concede it is a coordination fix, not a regulatory one. It does not impose a mandatory speed limit inside the Bay. But it would put dedicated eyes inside the room where the broadcasts are made.

Why this time may be different

Giancarlo Rulli, the Marine Mammal Center’s associate director of public relations and a 22-year volunteer at the Sausalito hospital, has been one of the most visible faces of the strandings response. In a phone interview this week, he made an argument that doesn’t fit on a press release: the gray whale’s storied resilience may be running out.

“It’s gone through a mass mortality event before, in 1999, 2000, and recovered,” Rulli said. “Only to have another one happen 20-plus years later. And in the years since, it is not recovering to the same degree, at all, that it did the first go around.”

NOAA’s most recent population estimate puts Eastern North Pacific gray whales at roughly 13,000 — down from 27,000 in 2016, the lowest count since the 1970s. Calf production in 2025 was 85, the lowest since records began in 1994. The Center for Biological Diversity’s October complaint cited “roughly 80 whales killed annually by vessel strikes on the West Coast.”

Gray whales make one of the longest migrations of any mammal — a 12,000-mile annual round trip between Arctic feeding grounds and the calving lagoons of Baja California. On the northbound leg, when they’re funneling through California waters in February through May, many of them arrive lean. The working theory among the biologists pulling the carcasses out of San Francisco Bay is that the whales now showing up inside the Golden Gate are hungry, and that the Bay — with its anchovy schools and ghost-shrimp-rich mudflats — looks like an emergency rest stop. The most visible evidence is the muddy plumes that surface as a whale rolls onto its right side and suction-feeds the bottom. Whether the whales are actually getting enough is another question.

Rulli said the Center is now actively trying to put extra eyes on the water in real time and is exploring whether individual whales might be tagged with location devices to help vessels avoid them. “Post-release tracking devices that we would typically use, like maybe an endangered species we’re caring for at our Sausalito hospital, cost anywhere between three and five-plus thousand dollars a pop,” he said. “And so, again, that’s where funding, resources, come into play. When we’re talking about two nonprofits that are doing everything we can, additional funding to assist not only on research but protective safety action is really critical.”

That, he said, is why the Marine Mammal Center has formally endorsed the Save Willy Act and the proposed cetacean desk inside the Coast Guard’s vessel-traffic service.

Whether grays are gaining real nutritional benefit from foraging in the Bay remains an open question even at the agency that pulls the carcasses. “We just don’t know, in terms of how much true sustenance they’re gaining by foraging in San Francisco Bay,” Rulli said. “There are other research groups that are looking at the content itself of what we’ve been able to gather in necropsy from stomach contents to try to decipher what’s being foraged on, likely small crustaceans and invertebrates. And just how much, if any, sustenance they’re gaining in terms of how much they’re eating, and is it overall improving their body condition? That’s something that we don’t have answers to at this point.”

Whale Smart and the gap policy isn’t closing

In the absence of mandatory rules, Marine Mammal Center Director of Cetacean Conservation Biology Kathi George has been quietly building the next line of defense: a vessel-operator training program called Whale Smart, launched in February in partnership with the San Francisco Harbor Safety Committee’s Marine Mammal Subcommittee, where George chairs the work group on vessel-strike risk. The program produces short-form training videos for professional mariners — Golden Gate Ferry, Blue & Gold Fleet, San Francisco Bay Ferry, City Cruises — on how to read whale behavior, recognize a “blow,” and slow down when the bay’s fog burns off into the conditions where strikes happen.

“Every action we take in San Francisco Bay matters,” George said when the program launched. “Whale Smart gives mariners the information they need to protect whales while maintaining safe and efficient operations, at a time when the species needs it most.”

It is the work that policy hasn’t done yet — training operators because regulators won’t compel them to slow down.

Moe Flannery, the California Academy of Sciences’ senior collections manager and a co-author on Slaathaug’s paper, framed the stakes plainly to the BBC: “It’s an immediate crisis that needs to be addressed, and this paper is just the first step in gathering the science that’s needed to help inform conservation and management of this species that’s in trouble.”

Back at RCA Beach, after the researchers had located the whale’s ear plug — the waxy deposit that allows scientists to estimate age — and packed up their samples, the carcass was left to the tide. Forty feet of evidence, surrendered to the same open Pacific the whale had peeled off from to enter the bay.

The next one is probably already on its way.