2025_programme: Detection and tracking of baleen whales using a subsea telecommunication cable on the Northwest Shelf of Australia

• Day: June 20, Friday
    Location / Time: A. TERPSIHORI at 08:50 - 09:10
• Last minutes changes: -
• Session: 05. Distributed Fiber-Optic Sensing technology for underwater acoustical monitoring
  Organiser(s): Alexander Gavrilov, Evgenii Sidenko, Hefeng Dong
  Chairperson(s): Hefeng Dong, Evgenii Sidenko
• Lecture: Detection and tracking of baleen whales using a subsea telecommunication cable on the Northwest Shelf of Australia
  Paper ID: 2302
  Author(s): Evgenii Sidenko, Alexander Gavrilov, Christine Erbe, Olivia Collet, Boris Gurevich, Henry Debens, Denise McCorry, Roman Pevzner
  Presenter: Evgenii Sidenko
  Abstract: Passive underwater acoustics is widely used for long-term acoustic monitoring of underwater environment and defense applications. Traditional hydrophones, developed over more than a century, offer broadband frequency capabilities with high signal-to-noise ratios. While highly effective, hydrophone-based passive acoustic monitoring of large ocean areas is costly, time-consuming, and rarely provides real-time solutions. Detecting and tracking underwater sound sources typically require multiple sensors, at least four for unambiguous source localization, arranged in a specific geometric configuration to estimate the time differences of arrival at different sensors and then the source location and bearing to it. Underwater telecommunication cables are widespread across continental shelves and often connect offshore industrial facilities. Unlit optical fibers of the telecom cables can be repurposed for distributed acoustic sensing (DAS), transforming cables into continuous acoustic sensor arrays with the interval between receivers down to 5 m. For this study, approximately two months of DAS data were collected from a 50-km cable on Australia’s Northwest Shelf. The dataset revealed various low-frequency underwater sound sources, such as marine vessels and great whales. This study examines DAS capability of tracking vocalizing pygmy blue and Omura’s whales, estimate the localization errors, and compare the detection range with that of conventional underwater passive acoustic systems. Adaptive acoustic beamforming is applied to different sections of the array used as sub-arrays of acoustic sensors for bearing and triangulation of vocalizing whales. To improve the accuracy of localization in relatively shallow water of around 100 m, phase velocities of normal modes in the sound field were estimated rather than assuming a mean sound speed for bearing estimates measurements. Most whales were localized and tracked within 10 km of the cable. DAS technology and the developed tracking approach demonstrate the potential for near-real-time acoustic monitoring and source tracking using existing subsea fiber-optic cables.
• Corresponding author: Dr Evgenii Sidenko
  Affiliation: CMST, Curtin University
  Country: Australia