Roch Marie

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Last Name
Roch
First Name
Marie
ORCID
0000-0002-0687-2059

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  • Article
    A practical guide for generating unsupervised, spectrogram-based latent space representations of animal vocalizations
    (Wiley, 2022-06-03) Thomas, Mara ; Jensen, Frants H. ; Averly, Baptiste ; Demartsev, Vlad ; Manser, Marta B. ; Sainburg, Tim ; Roch, Marie ; Strandburg-Peshkin, Ariana
    1. Background: The manual detection, analysis and classification of animal vocalizations in acoustic recordings is laborious and requires expert knowledge. Hence, there is a need for objective, generalizable methods that detect underlying patterns in these data, categorize sounds into distinct groups and quantify similarities between them. Among all computational methods that have been proposed to accomplish this, neighbourhood-based dimensionality reduction of spectrograms to produce a latent space representation of calls stands out for its conceptual simplicity and effectiveness. 2. Goal of the study/what was done: Using a dataset of manually annotated meerkat Suricata suricatta vocalizations, we demonstrate how this method can be used to obtain meaningful latent space representations that reflect the established taxonomy of call types. We analyse strengths and weaknesses of the proposed approach, give recommendations for its usage and show application examples, such as the classification of ambiguous calls and the detection of mislabelled calls. 3. What this means: All analyses are accompanied by example code to help researchers realize the potential of this method for the study of animal vocalizations.
  • Article
    Acoustic differentiation of Shiho- and Naisa-type short-finned pilot whales in the Pacific Ocean
    (Acoustical Society of America, 2017-02) Van Cise, Amy M. ; Roch, Marie ; Baird, Robin W. ; Mooney, T. Aran ; Barlow, Jay
    Divergence in acoustic signals used by different populations of marine mammals can be caused by a variety of environmental, hereditary, or social factors, and can indicate isolation between those populations. Two types of genetically and morphologically distinct short-finned pilot whales, called the Naisa- and Shiho-types when first described off Japan, have been identified in the Pacific Ocean. Acoustic differentiation between these types would support their designation as sub-species or species, and improve the understanding of their distribution in areas where genetic samples are difficult to obtain. Calls from two regions representing the two types were analyzed using 24 recordings from Hawai‘i (Naisa-type) and 12 recordings from the eastern Pacific Ocean (Shiho-type). Calls from the two types were significantly differentiated in median start frequency, frequency range, and duration, and were significantly differentiated in the cumulative distribution of start frequency, frequency range, and duration. Gaussian mixture models were used to classify calls from the two different regions with 74% accuracy, which was significantly greater than chance. The results of these analyses indicate that the two types are acoustically distinct, which supports the hypothesis that the two types may be separate sub-species.