The Guardian
Ferries, cargo vessels, and tankers navigate the turbulent waters of San Francisco Bay, often unaware of the whales surfacing nearby, their spouts barely detectable amidst the white caps. A newly launched AI-powered detection network, known as WhaleSpotter, aims to address this issue by tracking whale activity around the clock.
This advanced system monitors the bay day and night for whale blows and heat signatures up to 2 nautical miles away, providing alerts to mariners to slow down or change course when whales are detected in the vicinity.
"They'll be able to make adjustments way before they get anywhere close," stated Thomas Hall, the director of operations for the San Francisco Bay ferry. "It will also allow us to collect data over time and identify where the whales are congregating, enabling us to modify our routes during whale season to steer clear of those areas entirely."
This initiative emerges in response to a troubling increase in gray whale fatalities in the bay. Last year, 21 deceased gray whales were reported within the wider Bay Area, marking the highest number in 25 years, as per the Marine Mammal Center, with at least 40% of these deaths attributed to ship strikes. In 2023, an additional 10 gray whales have already been confirmed dead in the Bay Area.
Experts indicate that these figures likely underestimate the actual impact, as a significant number of whale carcasses sink or are washed out to sea before being discovered or reported.
Historically, gray whales have migrated along the California coast on their extensive 12,000-mile journey between breeding lagoons in Mexico and feeding grounds in the Arctic. However, an increasing number are now diverting into San Francisco Bay and lingering for extended periods, a trend scientists are increasingly connecting to the impacts of climate change. A 2023 study published in Science suggests that warming temperatures and changing sea ice conditions in the Arctic are disrupting the food resources that gray whales depend on during their summer feeding periods, leading to malnourishment as they migrate.
Currently, many whales are concentrated in a high-traffic area between Angel Island, Alcatraz, and Treasure Island, which directly intersects with ferry routes and shipping lanes.
"It's the worst possible location in terms of all the ship traffic," remarked Rachel Rhodes, a project scientist at the Benioff Ocean Science Laboratory who spearheaded the project. The frequency of collisions has been so high that "the teams responding to strandings stated they ran out of places to even land dead whales."
The eastern North Pacific gray whale population was once recognized as a conservation achievement, successfully recovering from commercial whaling and being removed from the Endangered Species Act in 1994. However, the population has since decreased by 50% over the past decade, according to the National Oceanic and Atmospheric Administration, leaving just 13,000 individuals remaining.
"They may not be getting the quality or quantity of food they traditionally relied upon in the Arctic," Rhodes explained. "This means they are commencing their incredibly long migration at a disadvantage."
The artificial intelligence system automatically flags potential whale sightings, which are subsequently verified by trained marine mammal observers prior to alerts being sent via radio to ferry operators, vessel traffic controllers, and publicly posted on the Whale Safe website.
WhaleSpotter technology is already in use on vessels and fixed installations, such as lighthouses and coastal towers, across the United States, Canada, and Australia. Nevertheless, researchers assert that the San Francisco Bay network is the first to seamlessly integrate both land-based and vessel-mounted detections with official mariner alerts, enabling near-real-time communication of whale sightings to vessels navigating the bay.
Initial testing yielded an immediate surge in detections.
"Having a comprehensive understanding of the whale activity in this area honestly made me feel a bit anxious," expressed Douglas McCauley, director of the Benioff lab. "However, we will utilize that data wisely to manage this space while sharing it with the whales."
Researchers highlight that the greatest advantage of the system lies in its ongoing monitoring capabilities. Unlike human observers, thermal imaging cameras can operate continuously, even during nighttime and in the frequent foggy conditions typical of the bay.
One camera has been installed on Angel Island, with plans for a second camera to be placed aboard a ferry operating between downtown San Francisco and Vallejo, creating what Rhodes refers to as a "moving data collection platform." Scientists hope to expand coverage further with additional cameras on the Golden Gate Bridge and Alcatraz.
A significant marine heatwave persisting off the coast of California is contracting the area of cold, nutrient-rich waters that sustain krill, anchovies, and sardines. As these offshore waters warm, humpback whales are increasingly following their prey closer to the shore, particularly in areas frequented by California's Dungeness crab fishery.
This fishery utilizes tens of thousands of vertical lines connecting traps on the seafloor to surface buoys, posing entanglement risks for whales that are migrating and feeding along the coast.
In response, regulators have once again closed portions of the fishery off central California to conventional gear. This action has become more common in recent years as rising sea temperatures increase overlapping timelines between whale activities and crab fishing.
While gray whales face their share of risks, humpback whales are particularly vulnerable.
"Humpbacks are curious creatures and may rub against the fishing gear," explained Kathi George, director of cetacean conservation biology at the Marine Mammal Center. "If a line becomes entangled on their body, they often breach and roll, further compounding the entanglement."
Whales can drag heavy gear for months, severely impacting their ability to dive or feed, which can result in starvation, infection, and even drowning.
In 2024, 36 confirmed whale entanglements occurred along the west coast, representing the highest count since 2018, according to the National Oceanic and Atmospheric Administration. Scientists caution that the majority of such incidents likely go undocumented.
California has initiated the commercial use of ropeless pop-up crab fishing gear for the first time this spring, enabling fishermen to continue their harvests through the end of the season without endangering whales.
Rather than employing traditional floating surface buoys tethered to traps, this innovative system stores ropes and buoys on the seafloor until fishermen return to trigger an acoustic release that brings the gear to the surface.
Proponents of the technology argue that it enables fishermen to maintain their livelihoods while significantly lowering the risks to whales.
As climate change continues to alter ocean conditions and whale migration patterns, scientists anticipate a sustained overlap between whales, ships, and fishing gear.
"We must remain adaptive and driven by scientific data when managing these issues to minimize risks to wildlife while ensuring that fishermen can remain active," asserted Caitlynn Birch, Oceana's Pacific campaign manager and a marine scientist. "California has emerged as a national leader in developing whale-safe fishing technologies, and we hope this model can be adopted by other fisheries along the West Coast and across the country."
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