"Some people talk to animals. Not many listen though. That's the problem."

-A.A. Milne

Acoustic Behavior and Tracking of Marine Mammals

An ongoing objective of passive acoustic research at NEFSC is to increase our understanding of the basic acoustic behavior of various marine mammal and fish species. A better understanding of the acoustic behavior of these species is important in order to assess and improve the effectiveness of passive acoustic monitoring as a tool for long-term monitoring and management.
spectrogram humpback whale breaching spectrogram of right whale upcall aerial photo of right whale

Long-term acoustic recordings are used to investigate the seasonal and spatial distributions of species with known call types. A primary goal is to contribute to the development of automated detectors to locate specific sounds within these recordings, allowing us to obtain useful information from large datasets.

Furthermore, we combine visual and acoustic data collection methods to better understand the species specific behavioral significance of known call types, as well as attribute unknown call types to species.

Arrays of simultaneously deployed recording units provide the opportunity to localize calls based on the time difference of their arrival on different receivers. Acoustic localization and tracking of marine mammals as they move through the array offers new insight on calling patterns and fine-scale movements, and allows a more informed comparison of acoustic data with visual sighting information. Localization data also allow the estimation of source energy levels for different call types and species. Additionally these data can improve our understanding of experienced sound levels and/or the behavioral reactions of groups of animals to passing vessels.

track of right whale acoustic group relative to cargo ship source location graph

Figure 1 (left): Spectrogram cross-correlation and the pattern of time delays across channels are used to estimate the position of a calling whale. Cornell Lab of Ornithology, XBAT, Figueroa & Robbins 2008; correlation sum estimation approach, Cortopassi & Fristrup, unpublished.

Figures 2 & 3 (right): From Maps of the acoustic tracks of singing humpback whales recorded during spring and fall 2009. Yellow dots indicate MARUs used for acoustic recording, localization, and tracking. Whale tracks are shown in red. From Stanistreet et al. 2013.

Spectrogram representation (time vs. frequency) of humpback whale song
Humpback whale (photo: NEFSC)
Spectrogram representation (time vs. frequency) of a right whale upcall
Right whale (photo: NEFSC)
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(File Modified Jan. 11 2018)