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Marie Zahn

Postdoctoral Scholar



Department Affiliation



B.A. Environmental Biology, Columbia University, Columbia College, 2016

PhD Aquatic & Fishery Sciences: Data Sci, University of Washington, 2023


2000-present and while at APL-UW

Acoustic differentiation and classification of wild belugas and narwhals using echolocation clicks

Zahn, M.J., S. Rankin, J.L.K. McCullough, J.C. Koblitz, F. Archer, M.H. Rasmussen, and K.L. Laidre, "Acoustic differentiation and classification of wild belugas and narwhals using echolocation clicks," Sci. Rep., 11, doi:10.1038/s41598-021-01441-w, 2021.

More Info

12 Nov 2021

Belugas (Delphinapterus leucas) and narwhals (Monodon monoceros) are highly social Arctic toothed whales with large vocal repertoires and similar acoustic profiles. Passive Acoustic Monitoring (PAM) that uses multiple hydrophones over large spatiotemporal scales has been a primary method to study their populations, particularly in response to rapid climate change and increasing underwater noise. This study marks the first acoustic comparison between wild belugas and narwhals from the same location and reveals that they can be acoustically differentiated and classified solely by echolocation clicks. Acoustic recordings were made in the pack ice of Baffin Bay, West Greenland, during 2013. Multivariate analyses and Random Forests classification models were applied to eighty-one single-species acoustic events comprised of numerous echolocation clicks. Results demonstrate a significant difference between species’ acoustic parameters where beluga echolocation was distinguished by higher frequency content, evidenced by higher peak frequencies, center frequencies, and frequency minimums and maximums. Spectral peaks, troughs, and center frequencies for beluga clicks were generally > 60 kHz and narwhal clicks < 60 kHz with overlap between 40–60 kHz. Classification model predictive performance was strong with an overall correct classification rate of 97.5% for the best model. The most important predictors for species assignment were defined by peaks and notches in frequency spectra. Our results provide strong support for the use of echolocation in PAM efforts to differentiate belugas and narwhals acoustically.

Acoustics Air-Sea Interaction & Remote Sensing Center for Environmental & Information Systems Center for Industrial & Medical Ultrasound Electronic & Photonic Systems Ocean Engineering Ocean Physics Polar Science Center