Ship noise threatens killer whales...and artificial intelligence techniques seek to save them

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(CNN) - Last September, 76 orcas arrived in the Salish Sea, marking the latest appearance of an endangered group known as the "Southern Resident Killer Whales."

Every year, the few remaining numbers of these whales head to Admiralty Strait, before continuing on to Puget Bay in the US state of Washington, where they move back and forth in its waters from late summer until early winter.

These whales are classified as one of the most endangered species, and they are among the few orca groups that depend on fish as a source of food.

This journey takes you through the fjords in search of Chinook salmon.

The noise resulting from heavy maritime traffic affects their ability to hunt, communicate, and locate their prey using echo, while ships pose an additional threat to their lives, due to the possibility of colliding with them.

In the 1970s, scientists determined that southern resident killer whales belong to a separate population that is genetically distinct from the more widespread "big" killer whales.

The first scientific survey of this group, conducted in 1974, showed that its numbers amounted to only 71 whales, before rising to 97 whales in 1996, then declining to 79 whales by 2001.

In 2005, this group was officially included on the endangered species list.

“Underwater noise is a widespread threat,” said Rachel Aronson, program director for Maritime Blue's Quiet Sound Initiative, which works to promote sustainable practices in the marine sector.

She added: "The higher the level of underwater noise, the more difficult it becomes for the killer whales residing in the south. Sometimes, these whales chase their prey without being able to catch it, which causes them to waste their energy without obtaining any food. At other times, they give up hunting completely, which raises concern, especially if the female is preparing to become pregnant or breastfeeding a young."

A study published in 2024 showed that increasing the maximum noise level by one decibel reduces the probability of females chasing their prey by 58%, and reduces the chances of males and females successfully catching prey by 12.5%.

Washington relies heavily on international trade, with about 40% of the state's jobs linked to it, which makes balancing the interests of the maritime sector with the requirements of protecting wildlife a very delicate task.

Building on the experience of the Canadian “Echo” program, the “Quiet Sound” initiative launched, in 2022, a voluntary program to encourage ships to reduce their speed, along a 20-mile sea route, towards Seattle, Tacoma and Everett, the three largest ports in the US state of Washington.

In general, slowing ship traffic reduces noise pollution.

Aaronson explained that the participation rate in the program has reached 73% so far, while underwater noise has decreased by up to 50% since the initiative began.

However, monitoring the movements of killer whales, specifically the group residing in the south, to avoid endangering them, remains a challenge.

In preparation for the whale migration to Puget Bay this year, the Quiet Sound Initiative collaborated with SMRU Consulting and Microsoft to launch an acoustic buoy equipped with artificial intelligence technologies to monitor whale sounds and track their presence.

SMRU Consulting, affiliated with the University of St Andrews in the United Kingdom, has developed a series of smart buoys since 2014.

They have already been used to monitor wildlife in Scotland, the East Coast of the United States and the Pacific Northwest, specifically in areas where human presence might disturb the animals.

Cormac Booth, the company's general manager, said monitoring of marine sounds has been ongoing for decades, but analyzing the data previously took several months after collecting it.

He explained that technological development has made it possible to go beyond archiving and subsequent analysis, adding: “Today we can provide reliable information about what is happening in real time, allowing immediate decisions to be made.”

In July 2025, SMRU Consulting partnered with Microsoft to develop a buoy that uses artificial intelligence to recognize the calls of killer and humpback whales.

“Underwater observations produce more audio recordings than humans can manually review,” said Juan La Vista Ferris, chief data scientist at Microsoft. “This is where artificial intelligence can process these amounts of data quickly and in near real-time.”

Microsoft provided an SMRU buoy with the WaterSpar system, an aquatic version of its AI-based wildlife monitoring technology.

It generally allows analysis of sounds, images and sensor data to identify different species.

In July, Microsoft and SMRU Consulting, in cooperation with the Quiet Sound Initiative, deployed a sonic buoy in the Harrow Strait, which straddles the border of Canada and the United States.

“This area is the most suitable area to have the greatest potential benefit in protecting southern resident whales,” said Jason Wood, chief scientist and deputy director of technology at SMRU Consulting.

The buoy includes three underwater microphones, or hydrophones, while the Microsoft system is located inside the buoy itself, and SMRU's analysis system is below the surface of the water.

According to Wood, the two systems are competing to determine which is more accurate in detecting the sounds of southern resident killer whales.

“The results so far are encouraging,” Ferris said. “After adapting the models to the nature of the underwater sounds in Puget Bay, and collecting more field data, the false alarms decreased to a level where the Water Sparrow became viable as an actual detection system.”

Wood explained that the buoy has not yet begun sending its data to the “WRAS” system, which is run by the “Ocean Wise” organization, to alert navigators of the locations of whales and avoid ship collisions with them, due to the possibility of false alarms being issued, but that may change.

The system relies on combining data from multiple sources, including human sightings, thermal imaging, and hydrophones, to create a map that identifies whale spotting locations.

According to Aaronson, captains of commercial ships receive a text alert when a whale is spotted within 10 nautical miles.

Wood pointed out that each method of monitoring has its limitations. Human sightings are often limited to daylight hours, thermal imaging monitors what appears near the surface of the water, while underwater microphones rely on whales issuing their calls.

However, he expressed his hope to enhance the accuracy of species monitoring and provide more useful information by employing artificial intelligence techniques in data analysis.

For his part, Ferris said that Microsoft is working to provide data on the seasonal patterns of killer whales, to support efforts to protect them and manage wildlife, with the possibility of expanding the experiment to include other species in the Salish Sea.

He pointed out that Microsoft seeks to make the Water Sparrow system available as an open source, like its land version, so that more agencies concerned with wildlife protection can use it and install it on other compatible buoys.

“Given the critical situation of this endangered group, the question is no longer whether these AI-powered buoys will be deployed, but rather when this will happen, as protecting the whales depends on this step,” Ferris said.