A tale of whale and fiber: monitoring baleen whales with Distributed Acoustic Sensing (DAS)

Distributed Acoustic Sensing (DAS) converts fibers in existing underwater telecommunication fiber-optic cables into dense listening arrays of strain sensors. Recent advances in DAS interrogating technology enable increasing data quality, spatial coverage, and bandwidth, sparking interest in applied environmental sensing. Initially focused on seismic data collection, e.g., for earthquake monitoring, DAS has demonstrated abilities in detecting waterborne acoustic sources, including the low-frequency sounds of blue and fin whales (Balaenoptera musculus and B. physalus) over tens of km of fiber. DAS is instrumented from land, collects data in near-real time, and offers region-wide spatial coverage. Thus, this technology provides a unique opportunity for robust monitoring of endangered and threatened migratory baleen whales at ecologically meaningful spatial and temporal scales. This talk will introduce our research on using DAS to monitor low-frequency baleen whales, including detection and tracking, and the open-access DAS4Whales python package, developed to analyze terabytes of spatio-temporal data collected with DAS. We will also address the potential limitations of this new monitoring technology and provide a roadmap for further research and testing needed to exploit the technology's full potential.