San Francisco Bay just installed a network of thermal cameras to track gray whales in real time — not because anyone wanted to build a marine surveillance grid, but because whale ship collisions have become routine enough to warrant one. Last year alone, 21 dead gray whales washed up in the Bay Area. At least 40% were killed by ships. Ten more have died this year already, and those are just the ones that didn’t sink or drift back out to sea before anyone noticed.
The system, called WhaleSpotter, scans the bay 24/7 for whale blows and heat signatures up to 2 nautical miles away. When it spots a whale, it sends alerts to ferry operators, vessel traffic controllers, and anyone checking the Whale Safe website. The idea is simple: if mariners know where the whales are, they can slow down or reroute before turning a 40-ton mammal into a statistic.
“They’ll be able to make adjustments way before they get anywhere close,” said Thomas Hall, director of operations for San Francisco Bay Ferry. “It will also allow us to track data over time and see where the whales are camping out so we can adjust our routes during whale season to avoid those areas completely.”
Except there’s a problem — the whales aren’t just passing through anymore. They’re staying.
Gray Whales Are Starving in the Arctic, So They’re Lingering in Shipping Lanes
Gray whales used to migrate along the California coast like clockwork: 12,000 miles from breeding lagoons in Mexico to feeding grounds in the Arctic, then back again. They’d pass offshore, barely visible from land, and that was that.
Not anymore.
Warming temperatures and shrinking sea ice in the Arctic are disrupting the food web gray whales depend on during summer feeding months — krill, amphipods, the usual suspects. A 2023 study in Science found that many whales are now arriving at their Arctic feeding grounds malnourished, which means they’re starting their southbound migration at a disadvantage. So instead of cruising past San Francisco Bay, they’re diverting inside, lingering for days or weeks, foraging in shallow waters where ferries, cargo ships, and tankers operate around the clock.
“It’s the worst place possible in terms of all the ship traffic,” said Rachel Rhodes, a project scientist at the Benioff Ocean Science Laboratory who led the WhaleSpotter initiative. There have been so many collisions that “the teams responding to strandings said they ran out of places to even land dead whales.”
The eastern North Pacific gray whale population was once a conservation success story — removed from the Endangered Species Act in 1994 after rebounding from commercial whaling. But numbers have since plummeted by half over the last decade. Just 13,000 remain.
“They may not be getting the quality or quantity of food they’re used to in the Arctic,” Rhodes said. “That means they’re starting this incredibly long migration at a disadvantage.”
So they’re stopping in San Francisco Bay to eat — right in the middle of one of the busiest shipping corridors on the West Coast.
Thermal Cameras Provide Real-Time Alerts — Because Human Observers Can’t Work 24/7
WhaleSpotter uses thermal cameras mounted on fixed installations, such as Angel Island, and aboard ferries traveling between San Francisco and Vallejo. The system scans the water for whale blows and heat signatures, flags potential sightings using machine learning, then routes them to trained marine mammal observers for verification. Once confirmed, alerts are broadcast via radio to mariners and posted publicly on the Whale Safe website.
The system is already used in the U.S., Canada, and Australia, but San Francisco’s network is the first to integrate land-based and vessel-mounted detections with official mariner alerts in near-real time.
The first hours of testing produced an immediate flood of detections.
“Suddenly to have a full sense of how much whale activity is in this space honestly put me a little bit on edge,” said Douglas McCauley, director of the Benioff lab. “But we’re going to use that data, and we’re going to be smart about how we use that space and share it with the whales.”
The system’s biggest advantage is constant monitoring. Unlike human observers, thermal cameras can operate through the night and in many foggy conditions common in the bay. Researchers hope additional cameras on the Golden Gate Bridge and Alcatraz could eventually expand coverage across the entire bay.
Humpback Whales Are Also at Risk — But From Fishing Gear, Not Ships
Gray whales aren’t the only ones in trouble. A severe marine heat wave lingering off the California coast is shrinking the band of cold, nutrient-rich water where krill, anchovies, and sardines thrive. As offshore waters warm, humpback whales are following that prey closer to shore — right into California’s Dungeness crab fishery, which uses tens of thousands of vertical lines connecting traps on the seafloor to surface buoys.
Those lines are entanglement hazards. Humpbacks are curious — they’ll scratch their backs on the gear, and if a line catches on their body, they’ll breach and roll, tangling themselves further.
“If they get a line caught on their body, they’ll breach, and they’ll roll and end up entangling themselves,” said Kathi George, director of cetacean conservation biology at The Marine Mammal Center.
Whales can drag heavy gear for months, unable to dive or feed properly, leading to starvation, infection, and drowning. Thirty-six whales were confirmed entangled off the West Coast in 2024 — the highest number since 2018 — though scientists caution most cases go undocumented.
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 have increased overlap between whale and crab fishing seasons.
California approved commercial use of ropeless pop-up crab fishing gear for the first time this spring, which allows fishermen to continue harvesting through the end of the season. Instead of floating surface buoys tethered to traps, the system stores ropes and buoys on the seafloor until fishermen return, after which it triggers an acoustic release that brings the gear to the surface.
Supporters say the technology allows fishermen to continue harvesting crab while dramatically reducing the risk to whales.
Climate Change Keeps Rewriting the Rules — And Nobody’s Keeping Up
As climate change reshapes ocean conditions and whale migration patterns, scientists expect the overlap between whales, ships, and fishing gear to persist.
“We will have to continue to be adaptive and science-driven in terms of our management to reduce wildlife risk and keep fishermen on the water,” said Caitlynn Birch, Oceana’s Pacific campaign manager and a marine scientist. “California has been a national leader in developing whale-safe fishing technologies, and we hope that model can help guide other fisheries on the West Coast and nationally.”
The thermal cameras are a start. The ropeless fishing gear is a start. But both are reactive measures to a problem that keeps accelerating — warmer oceans, shrinking food supplies, whales showing up in places they didn’t use to go, and humans scrambling to adjust shipping lanes and fishing seasons on the fly.
The whales didn’t ask to be in the ferry lanes. They’re just trying to eat.