SAN JUAN ISLAND, Wash. — As dawn broke, a group of researchers from the University of Washington embarked on a crucial mission to deploy over a mile of fiber-optic cable into the chilly waters of the Salish Sea. The primary goal? To utilize the same technology that carries internet signals to create an underwater microphone that could capture the clicks, calls, and whistles of endangered Southern Resident orcas. The ability to monitor these vocalizations is critical for understanding how this vulnerable population interacts with environmental challenges—primarily food scarcity, underwater noise pollution, and climate change.

This experiment, spearheaded by scientists from the University of Washington's School of Oceanography, involves a technology known as Distributed Acoustic Sensing (DAS). Unlike conventional hydrophones that capture sound from a fixed point, DAS transforms an entire fiber-optic cable into a sensory network capable of pinpointing the exact location of aquatic animals while monitoring their movements.

We can imagine thousands of hydrophones along the cable recording data continuously, said Shima Abadi, professor at the University of Washington. We can know where the animals are and learn considerably more about their migration patterns compared to traditional methods.

Orcas rely on echolocation to hunt for salmon, but ship traffic is causing disruptive background noise, further endangering their survival. If the DAS project proves successful, it may not only provide real-time alerts to protect these majestic creatures but could also facilitate conservation management and inform future marine protected areas. As the project advances, important questions about orca behavior and vocalization patterns remain to be explored, highlighting the critical need for a reliable dataset. As the world prepares for the upcoming High Seas Treaty, the implications of this project could extend well beyond local waters, paving the way for an expansive global network for marine monitoring.