OERA Webinar Series – Hansen Johnson, Dalhousie University

October 25, 2018 – 1:00 – 2:00 pm AST
Hansen Johnson, Dalhousie University
“Measuring the acoustic detection range of large whales from autonomous platforms to improve an acoustic whale alert system”

There is significant concern about the risk that offshore marine industries pose to endangered whales. One mitigation strategy is to use autonomous platforms (e.g., ocean gliders and buoys) equipped with a near real-time passive acoustic monitoring (PAM) system to alert ocean users to whale presence. To effectively use passive acoustics to monitor marine mammals, an understanding of the area over which the monitoring system can detect each species of interest is absolutely critical. The main goal of this study was to determine the range-dependent accuracy of our whale monitoring system on mobile and fixed platforms. We deployed a PAM-equipped Slocum glider and moored buoy alongside a hydrophone array during the spring of 2017 approximately 15 km Southwest of Martha’s Vineyard, USA. We applied signal processing techniques to the array data to determine the position of each calling whale. We then compared the acoustic records from all three platforms to quantify the effective monitoring area of each system. The results help us to better understand and improve the performance of our monitoring system, which in turn allows us to disseminate more accurate information about whale distribution to research, government, and industry stakeholders.