Including Whale Call Detection in Standard Ocean Measurements: Application of Acoustic Seagliders

Abstract

Over the past decade, fixed recorders have come into increasing use for long-term sampling of whale calls in remote ocean regions. Concurrently, the development of several types of autonomous underwater vehicles has demonstrated measurement capabilities that promise to revolutionize ocean science. These two lines of technical development were merged with the addition of broadband (5 Hz to 30 kHz) omni-directional hydrophones to seagliders. In August 2006, the capability of three Acoustic Seagliders (ASGs) to detect whale calls was tested in an experiment offshore Monterey, California. In total, 401 dives were completed and over 107 hours of acoustic data recorded. Blue whale calls were detected on all but two of the 76 dives where acoustic data were analyzed in detail, while humpback and sperm whale calls were detected on roughly 20% of those dives. Various whistles, clicks and burst calls, similar to those produced by dolphins and small whales, were also detected, suggesting that the capability of ASGs can be expanded to sample a broad range of marine mammal species. The potential to include whale call detection in the suite of standard oceanographic measures is unprecedented and provides a foundation for mobile sampling strategies at scales that better match the vertical and horizontal movements of the whales themselves. This capability opens new doors for investigation of cetacean habitats and their role in marine ecosystems, as envisioned in future ocean observing systems.

Crowdsourcing Modern and Historical Data Identifies Sperm Whale (Physeter macrocephalus) Habitat Offshore of South-Western Australia

“…New autonomous technologies such as ocean gliders and wave gliders may be the next step in providing a platform for passive acoustic monitoring of sperm whales as they operate over large distances for days at a time in any sea condition and have the potential to transmit data via satellite (Moore et al, 2007;Dassatti et al, 2011;Bingham et al, 2012). In light of current technology, understanding of sperm whale bioacoustics, and their habitat preferences, there is ample support for undertaking long-term passive acoustic studies to monitor the population within the EEZ waters in the Perth and Albany canyons in order to inform future marine management and policy decisions.…”

Real-time reporting of baleen whale passive acoustic detections from ocean gliders

“…The vast majority of passive acoustic monitoring applications today utilize moored acoustic recorders for which the archived audio is not accessible until after recovery (typically months after deployment) and species-specific call detections are unavailable until after analysis (typically months to years after recovery). Passive acoustic recording has also been conducted from autonomous mobile platforms (e.g., ocean gliders, profiling floats; Moore et al, 2007;Baumgartner and Fratantoni, 2008), but detection data are similarly unavailable until the platform is recovered and the audio is analyzed. Recent advances in low-power digital a) Author to whom correspondence should be addressed.…”

Monterey Bay ambient noise profiles using underwater gliders

“…Gliders have been used for acoustic applications such as detecting low frequency sources (Howe and Boyd (2008)), whales (Moore et al (2007)) and fish sounds (Wall et al (2012)). The works by Howe and Boyd (2008) and Moore et al (2007) used internal hydrophones.…”

“…The works by Howe and Boyd (2008) and Moore et al (2007) used internal hydrophones. The work by Wall et al (2012) used external hydrophones, but to detect nearby fish sounds.…”