As dawn broke over San Juan Island, a group of scientists stood on a barge, carefully lowering more than a mile of fiber-optic cable into the cold waters of the Salish Sea — home to the region’s endangered orcas.
Their experiment aims to turn the same fiber-optic strands that transmit global internet data into a continuous underwater microphone, capable of capturing the clicks, calls, and whistles of whales. The data could help reveal how orcas react to ship traffic, food scarcity, and climate change. If successful, the thousands of miles of fiber-optic cables already stretched across the ocean floor could become part of a vast listening network for marine conservation worldwide.
The technology, known as Distributed Acoustic Sensing (DAS), was originally designed to monitor pipelines and detect infrastructure issues. Researchers at the University of Washington are now adapting it to “listen” to the ocean. Unlike traditional hydrophones that record sound from a single location, DAS converts an entire cable into a massive array of sensors, allowing scientists to track an animal’s exact position and direction.
“We can imagine having thousands of hydrophones along the cable recording data continuously,” said Shima Abadi, professor at the University of Washington Bothell School of STEM and the School of Oceanography. “It enables us to locate animals more accurately and better understand their migration patterns.”
The technology has already worked with large baleen whales. In earlier tests off the Oregon coast, researchers used existing telecom cables to detect the low-frequency rumbles of fin and blue whales.
But orcas present a tougher challenge. Their sounds occur at much higher frequencies — a range in which the DAS system has not yet been tested.
A race against extinction
The urgency is clear. The Southern Resident orcas that inhabit the Salish Sea are critically endangered, with only about 75 individuals remaining. They face a combination of threats: underwater noise, toxic pollution, and a shrinking food supply.
“We have an endangered killer whale trying to eat an endangered salmon species,” said Scott Veirs, president of Beam Reach Marine Science and Sustainability, which develops open-source acoustic tools for whale conservation.
Populations of Chinook salmon, the orcas’ main prey, have plummeted by 60% since 1984 due to habitat loss, overfishing, dams, and climate change. Because orcas hunt using echolocation — emitting rapid clicks that bounce off fish — loud ship noise can interfere with their ability to locate food.
If DAS proves successful, scientists could use it to gather real-time data to protect the whales. For instance, if the system detects orcas moving south toward Seattle, it could alert Washington State Ferries to delay noisy operations or slow vessels until the whales pass.
“It will certainly help improve dynamic management and long-term policy with real benefits for the whales,” Veirs said.
The system could also help answer fundamental questions about orca behavior — such as how their communication changes in different situations, how they coordinate while hunting, or even which individual whale is making a particular sound.
A global opportunity
The implications extend beyond the Salish Sea. With roughly 870,000 miles (1.4 million km) of underwater fiber-optic cables already in place worldwide, much of the infrastructure for large-scale ocean monitoring already exists. It simply needs to be repurposed.
“One of the biggest challenges in wildlife conservation and climate research is the lack of data,” said Yuta Masuda, director of science at Allen Family Philanthropies, one of the project’s funders.
The timing is also crucial. The High Seas Treaty, which takes effect in January, will enable the creation of new marine protected areas in international waters. However, scientists still lack comprehensive data on how human activity affects ocean life — information that fiber-optic networks could help provide.
“We think this approach has enormous potential to fill those critical data gaps,” Masuda said.
Back on the barge, the researchers faced a delicate task: fusing two fragile fiber strands above the rolling waves. Using a precision fusion splicer, they struggled to align the fibers before melting them together with an electric current. After several failed attempts, the weld finally held.
Soon, data began streaming to a shore-based computer, forming colorful “waterfall plots” that visualize sound frequencies over time. Nearby cameras stood ready to record the moment an orca call was detected — linking sound with behavior.
With the system in place, the team could only wait — and hope the whales would come.
Source: AP