San Francisco Bay became a whale death trap. This new tech could help reverse the trend.

On a sunny Tuesday in the San Francisco Bay, the spout of a gray whale emerged from the depths and sent a heart-shaped cloud of mist into the air. But right behind the majestic marine mammal was a tanker the size of a building, and it was getting closer.

It’s now a common scene in the Bay. With their Arctic food supply dwindling, more migrating gray whales have been making pit stops in San Francisco Bay to search for food, putting them directly in the path of tankers, ferries, cruise ships, and cargo vessels, leading to fatal ship strikes. A recent study revealed that around 18 percent of the gray whales that entered the Bay between 2018 and 2025 died there. At least seven gray whales have died in the Bay this year, and experts estimate that at least 40 percent of those deaths were caused by ship strikes.

But, in typical San Francisco fashion, a new piece of technology has been developed to alleviate the problem. On May 19, local scientists, conservationists, ferry operators, and government officials gathered on Angel Island—a small island in the heart of the Bay overlooking the skyline—to celebrate the installation of an AI-powered whale monitoring device atop its western peak. 

The device—developed by WhaleSpotter, a company dedicated to whale tech—uses thermal imaging to detect heat signatures from whale spouts; it pinpoints their location up to four miles away. 

Once the system’s AI detects a whale, an expert who works with WhaleSpotter verifies it and posts its location to the website Whale Safe, where it can be monitored by anyone, including law enforcement, the public, and ship captains, who have the website open on their dashboards. Conservationists hope that this new technology will help ship captains steer clear of gray whales in San Francisco Bay and that the device on Angel Island will be the first of many.

Thermal detection technology is already being used to avoid strikes with elusive orcas in the Pacific Northwest, and scientists are currently testing it on the East Coast to see if it can help reduce the number of ship collisions with critically endangered North Atlantic right whales.

Gray area

The sight of a gray whale breaching beneath the Golden Gate Bridge is undoubtedly beautiful, but that beauty belies an ugly truth: Gray whales don’t belong in San Francisco Bay. 

Gray whales make the longest migration of any mammal, traveling 12,000 miles round-trip from their feeding grounds in the Arctic to their breeding grounds off the coast of Baja California. In the Arctic, they gorge themselves on bottom-dwelling crustaceans, which they catch by swimming along the seafloor on their sides and scooping up mouthfuls of mud. But outside the Arctic, these whales rarely eat. Their migrations are almost entirely powered by their fat reserves.  

However, climate change has reduced the amount of prey for gray whales in the Arctic, forcing them to embark on their epic migrations without enough gas in the tank. By the time they reach San Francisco Bay, many are starving. 

“What does climate change look like? It looks like skinny whales coming into the Bay, digging for food,” says Douglas McCauley, director of the Benioff Ocean Science Laboratory at the University of California, Santa Barbara. McCauley, who helped pioneer Whale Safe, says that before 2018, the presence of the occasional gray whale in the Bay wasn’t necessarily a cause for alarm, but times have changed. 

After humans hunted gray whales out of the Atlantic in the 18th century, the species now survives only in two Pacific populations. The larger of the two has undergone a roughly 50 percent decline over the last decade, dropping from a peak of nearly 23,000 whales to about 13,000.

“Every single whale that comes in the Bay, we gotta get back out,” says McCauley. "If ever there was a moment to even be doing incremental gains, it would be right now.”

Eyes in the sky

Ship strikes aren’t unique to San Francisco Bay. Along the U.S. West Coast, at least 118 whales were fatally struck by ships between 2015 and 2024, and those are just the ones scientists know about. Ships can fatally strike a whale without those on board even knowing it, and many whales struck by ships die from blunt force trauma or propeller lacerations, quickly sinking to the bottom, never to be seen again. 

In many places, ships are asked or required to reduce their speed to 10 knots—that’s about 11 mph—in areas where whales are present. (Gray whales typically swim at half that speed.) However, this alone hasn’t stopped whales from being struck by ships. That’s why in San Francisco, the Coast Guard’s Vessel Traffic Service will often alert captains via radio when they are approaching a whale. But their network of spotters can’t cover the entire bay, and they only work 12 hours a day. That’s where the new technology comes in. 

Having a whale spotting device atop Angel Island will be game-changing, says Gary Reed, director of the Vessel Traffic Service in San Francisco. "It’s like an extra set of eyes… We did great 12 hours a day, but now we can do 24.”

“It’s very promising,” adds Anna Nisi, a wildlife ecologist at the University of Washington, who wasn’t involved with the new tech. She notes that whale-spotting cameras should not replace existing measures such as vessel speed limits, which can further eliminate strikes. Nevertheless, “whale detection technology is a really useful new tool in the toolbox.” 

Back on Angel Island, within hours of being turned on, the thermal camera had detected dozens of spouts—one of which came from the whale swimming by the tanker. Watching from beneath the WhaleSpotter atop Angel Island, Reed turned on his radio and relayed the whale’s position to his team. But his team already knew from monitoring Whale Safe, and they’d alerted the tanker’s captain. They’d also received an alert from a local whale-watching boat.

The whale, it seemed, was in good hands. The ship and the whale parted ways. Hopefully, they will never cross paths again.