San Francisco, California– Ferries, cargo ships and tankers crossed the choppy waters of San Francisco Bay on Tuesday, as a whale appeared nearby, its snout barely visible against its white caps. Until now, whales could easily go unnoticed by sailors, but an AI-powered detection network launched this week is designed to track them day and night.
The system, called WhaleSpotter, scans the bay around the clock for whale strikes and heat signatures up to two nautical miles away, alerting sailors to slow down or redirect when whales are nearby.
“They’ll be able to make adjustments before they get anywhere close,” said Thomas Hall, director of operations for the San Francisco Bay Ferry. “It will also allow us to track data over time and see where whales are camping so we can adjust our routes during whale season to completely avoid those areas.”
These efforts come amid a worrying rise Gray whale death In the Gulf. Last year, 21 gray whales were found dead in the wider Gulf region — the highest number in 25 years, according to the Marine Mammal Center — with at least 40% killed by ship strikes. At least 10 others have died in the Bay Area so far this year.
Scientists say these numbers likely underestimate the true number, as many whale carcasses sink or drift out to sea before they are found or reported.
Gray whales have long been migrating along the California coast on their roughly 12,000-mile (19,300-kilometer) journey between breeding lakes in Mexico and feeding grounds in the Arctic.
But instead of simply passing offshore, increasing numbers are now turning into San Francisco Bay and staying for days or even weeks within the crowded estuary — a shift that scientists are increasingly linking to… Climate change. High temperatures Shifts in Arctic sea ice are Disrupting the food web Gray whales depend on feeding during the summer months, according to A 2023 Study in ScienceWhich led to many people suffering from malnutrition during the migration.
Many of the whales are now concentrated in a dense traffic corridor between Angel Island, Alcatraz and Treasure Island, directly overlapping ferry routes and shipping lanes.
“It’s the worst possible place in terms of ship traffic,” said Rachel Rhodes, a project scientist at the Benioff Oceanographic Laboratory who led the initiative. There were so many collisions that “teams responding to the stranding said they ran out of places to land dead whales.”
Gray whale populations in the eastern North Pacific have been hailed as a conservation success story following their recovery from commercial whaling and removal from the Pacific Ocean. Endangered Species Act in 1994. But numbers have declined since then, falling by half over the past 10 years, according to the National Oceanic and Atmospheric Administration. Only 13,000 left
“They may not be getting the quality or quantity of food that they are used to in the Arctic,” Rhodes said. “This means they started this incredibly long migration at a disadvantage.”
AI automatically identifies potential whale sightings, which are then verified by trained marine mammal spotters before alerts are sent via radio to ferry operators and ship traffic controllers and posted publicly on Safe whale Website.
WhaleSpotter systems are already used on ships and fixed structures such as lighthouses and coastal towers in the United States, Canada and Australia. But researchers say the San Francisco Bay Network is the first to directly integrate ground-based and ship-mounted detections with official mariner alerts, allowing whale sightings to be relayed in near real-time to ships navigating the Bay.
The first hours of testing produced an immediate torrent of discoveries.
“Suddenly, I had a complete idea of how active whales are in this space, and it made me feel a little nervous,” said Douglas McCauley, director of Benioff’s lab. “But we will use that data and we will be smart about how we use that space and share it with the whales.”
Researchers say the biggest advantage of this system is continuous monitoring. Unlike human observers, thermal cameras can operate during the night and in many of the foggy conditions common in the Gulf.
One camera has been installed on Angel Island, and another will soon be installed on a ferry traveling between downtown San Francisco and Vallejo to create what Rhodes described as a “mobile data collection platform.” Scientists hope that additional cameras on the Golden Gate Bridge and Alcatraz will eventually be able to expand coverage across the Gulf.
A residual extreme marine heatwave off the California coast is shrinking the range of cold, nutrient-rich waters where krill, anchovies and sardines thrive. As marine waters warm, humpback whales are increasingly pursuing that prey closer to shore, where California’s lobster fisheries operate.
The fishery uses tens of thousands of vertical lines that connect seafloor traps to surface buoys, creating entanglement risks for migrating and feeding whales along the coast.
This spring, regulators again closed parts of the fishery off central California to conventional gear, a measure that has become increasingly common in recent years as warming waters increasingly overlap whales with lobster fishing seasons.
While gray whales are also at risk, humpback whales are the most vulnerable.
“Humpback whales are curious, and will scratch their backs on equipment,” said Cathy George, director of cetacean conservation biology at the Marine Mammal Center. “If they get a string stuck to their body, it will break and they will roll around and end up getting tangled.”
Whales can drag heavy equipment for months, unable to dive or feed properly, leading to starvation, infection and drowning.
Thirty-six whales have been confirmed stranded off the West Coast in 2024 — the highest number since 2018, according to NOAA — although scientists warn that most cases go undocumented.
The state of California has approved commercial use of ropeless pop-up crab fishing gear for the first time this spring, which will allow fishermen to continue fishing through the end of the season.
Instead of floating surface buoys tied to traps, the system stores ropes and buoys on the sea floor until fishermen return and emit a sound that lifts the gear to the surface.
Proponents say the technology allows fishermen to continue catching crab while greatly reducing the risks to whales.
As climate change Reshapes the ocean Because of the conditions and migration patterns of whales, scientists expect continued interference between whales, ships, and fishing gear.
“We will have to continue to adapt and rely on science in our management to reduce wildlife risks and keep hunters in the water,” said Caitlin Birch, Oceana’s Pacific Campaign Director and a marine scientist. “California has been a national leader in developing safe whaling techniques and we hope this model will help guide other fisheries on the West Coast and nationally.”
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