In September, 76 southern resident killer whales entered the Salish Sea, representing the remaining members of an endangered population that returns to the region each year. They travel through Admiralty Inlet toward Puget Sound, moving through those waters from late summer until early winter.

These orcas are among the few killer whale communities that depend on fish. They enter the fjords to hunt Chinook salmon, but heavy maritime traffic creates noise that can interfere with hunting, communication and echolocation while vessels also present a deadly collision risk.

Scientists did not recognize southern residents as a genetically distinct group from the more populous Bigg’s killer whale until the 1970s. The first survey in 1974 counted 71 whales, with the population reaching 97 in 1996 before declining to 79 in 2001.

The southern resident killer whale was listed as endangered in 2005. Rachel Aronson, program director of Quiet Sound, an initiative within Maritime Blue that promotes sustainable maritime practices, described the scale of the acoustic problem plainly: “Underwater noise is a pervasive threat.”

Aronson said loud conditions can make it harder for the whales to find food. Some expend energy pursuing prey without success, while others may abandon hunting, creating particular concerns for females preparing for pregnancy or nursing a baby.

A 2024 study quantified the effect. For every one decibel increase in maximum noise level, females were 58% less likely to pursue prey, while males and females were 12.5% less likely to capture prey.

The conservation challenge intersects with Washington’s dependence on maritime commerce. In the state, 40% of jobs are tied to international trade, making the balance between protecting wildlife and maintaining shipping activity especially delicate.

Quiet Sound introduced a voluntary ship slowdown program in 2022, following a model used by its Canadian counterpart, the Echo Program. The effort covers a 20 mile stretch approaching Seattle, Tacoma and Everett, Washington’s three largest ports.

Slower vessels produce less noise. Aronson said participation reached 73% this season, while underwater noise has fallen by as much as 50% since the voluntary slowdown began.

Locating the whales, particularly southern residents, remains difficult. Before their migration to Puget Sound this year, Quiet Sound joined SMRU Consulting and Microsoft to launch an acoustic buoy using AI to listen for killer whale calls.

SMRU Consulting, a subsidiary of the University of St Andrews in the United Kingdom, has developed smart buoys since 2014. The technology has monitored wildlife in Scotland, the US East Coast and the Pacific Northwest, including places where a human presence could cause disturbance.

In July 2025, SMRU Consulting and Microsoft began a partnership to create and test whether AI aboard a buoy could correctly recognize killer whale and humpback whale calls. Microsoft equipped an SMRU buoy with Water SPARROW, an aquatic version of its wildlife monitoring AI.

Water SPARROW processes images, audio and sensor data for species identification. Working with Quiet Sound, Microsoft and SMRU Consulting launched their Communications Acoustics Buoy in July and placed it in the Haro Strait, which spans the Canada US border.

The buoy uses three hydrophones anchored underwater. Microsoft’s system floats inside the buoy, while SMRU’s analysis system sits below the surface, allowing the teams to compare which system detects southern resident killer whale signals most accurately.

“The results so far are encouraging,” said Juan Lavista Ferres, Microsoft’s chief data scientist and corporate vice president, and lab director of the Microsoft AI for Good Lab. As researchers adapted the models and collected more field data, false positives declined enough for Water SPARROW to function as a detection system.

Because false positives remain a concern, the buoy has not started sending findings to the Whale Report Alert System, a conservation tool managed by Ocean Wise. That system combines human sightings, thermal imaging and hydrophones to create a map of whale locations and help prevent ship strikes.

Commercial marine pilots receive a text alert when a phone is within 10 nautical miles of a whale sighting. Aronson said the advance warning matters because large vessels can require five miles to slow down.

Each detection method has limitations. Human observations occur mainly during daylight, thermal imaging is mostly limited to the surface, and hydrophones work when whales are calling, but SMRU principal scientist Jason Wood said combining those datasets with AI could eventually improve species detection.

Microsoft also wants to provide information about seasonal killer whale patterns for wildlife managers and conservationists, with the model potentially extending to other Salish Sea species. Ferres said Water SPARROW is also intended to become open source and available for compatible buoys used by more conservationists.