San Francisco launches AI whale detection to prevent ship strikes

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Ferries, cargo ships and tankers moved through choppy waters in San Francisco Bay on Tuesday as a whale surfaced nearby, its spout barely visible above the white caps. Until recently, whales could go unnoticed by mariners in those conditions, but the Bay has now launched an AI-powered detection network designed to track whales around the clock.

The system, called WhaleSpotter, is meant to detect whale blows and heat signatures and to help crews adjust their routes when whales are nearby. WhaleSpotter scans the bay continuously and can alert mariners to whales up to 2 nautical miles away, with the goal of reducing the risk of deadly collisions.

Thomas Hall, director of operations for San Francisco Bay Ferry, said the system would give crews time to respond before ships get close. He also said the approach would support longer-term tracking to show where whales are “camping out,” so routes during whale season can be adjusted to avoid those areas, rather than reacting only after contact.

The effort comes amid what researchers and conservation groups described as an alarming rise in gray whale deaths in the wider Bay Area. The Marine Mammal Center reported that 21 dead gray whales were found there last year, the highest number in 25 years, and said at least 40% were killed by ship strikes. At least 10 more gray whales have died in the Bay Area so far this year, and scientists say the true toll may be higher because carcasses can sink or be swept back out to sea before they are found and reported.

Officials and scientists said the conservation challenge has shifted as well as intensified. Gray whales have long migrated along the California coast on a roughly 12,000-mile journey between breeding lagoons in Mexico and feeding grounds in the Arctic, but researchers said more whales are now diverting into San Francisco Bay and lingering for days or even weeks in the crowded estuary. They increasingly link that change to climate change, saying warming temperatures and shifts in Arctic sea ice disrupt the food web gray whales rely on during summer feeding months, leaving them malnourished during migration.

Rachel Rhodes, a project scientist at the Benioff Ocean Science Laboratory who led the initiative, said the concentration of whales overlaps with a high-traffic corridor in the bay between Angel Island, Alcatraz and Treasure Island—directly intersecting ferry routes and shipping lanes. She said the amount of collision risk has become so high that response teams treating stranded whales have sometimes “run out of places to even land dead whales.”

The technology behind WhaleSpotter blends AI screening with human verification. Researchers said artificial intelligence flags potential whale sightings, and trained marine mammal observers then verify those sightings. After verification, alerts go through radio channels to ferry operators and vessel traffic controllers, and detections are also posted publicly on the Whale Safe website.

Researchers said WhaleSpotter systems already exist on vessels and fixed installations elsewhere in the United States, Canada and Australia, but that the San Francisco Bay project is distinctive because it integrates land-based and vessel-mounted detections with official mariner alerts. Douglas McCauley, director of the Benioff lab, said early testing produced a “flood of detections,” and he described the surprise at the scale of whale activity as something that put him “a little bit on edge.”

McCauley said the system’s value comes from constant monitoring that can operate through the night and in foggy bay conditions, when human observations can be limited. Researchers installed a camera on Angel Island and planned another camera aboard a ferry traveling between downtown San Francisco and Vallejo, described as a “moving data collection platform,” with scientists hoping to expand coverage with additional cameras on the Golden Gate Bridge and Alcatraz.

The whale-detection push is also unfolding alongside other climate-linked risks to marine mammals. Researchers described a severe marine heat wave off the California coast that is shrinking the band of cold, nutrient-rich water where prey species such as krill, anchovies and sardines thrive, pushing humpback whales closer to shore. They said humpbacks are increasingly drawn into areas near the Dungeness crab fishery, where fishing gear creates entanglement hazards.

Kathi George, director of cetacean conservation biology at The Marine Mammal Center, said humpbacks can get lines caught on their bodies and may breach and roll in ways that lead to entanglement. She described how whales can then drag heavy gear for months, becoming unable to dive or feed properly, and may die from starvation, infection or drowning.

NOAA statistics cited by the researchers showed 36 whales confirmed entangled off the West Coast in 2024, described as the highest number since 2018, while scientists cautioned that many cases go undocumented. For this spring, California approved commercial use of ropeless pop-up crab fishing gear for the first time, replacing surface buoys tethered to traps with gear stored on the seafloor until fishermen return and trigger an acoustic release that brings the equipment to the surface.

Supporters said the technology would allow continued crab harvesting while reducing the risk to whales. Caitlynn Birch, Oceana’s Pacific campaign manager and a marine scientist, said California had developed whale-safe fishing technologies and hoped the approach could guide other fisheries as climate change reshapes ocean conditions and whale migration patterns, increasing the overlap between whales, ships and fishing gear.