title: Description and clustering of echolocation signals of Commerson's dolphins (Cephalorhynchus commersonii) in Bahía San Julián, Argentina.
abstract: Commerson's dolphins (Cephalorhynchus commersonii) inhabit coastal waters of Southern South America and Kerguelen Islands. Limited information exists about the acoustic repertoire of this species in the wild. Here, echolocation signals from free-ranging Commerson's dolphins were recorded in Bahía San Julián, Argentina. Signal parameters were calculated and a cluster analysis was made on 3180 regular clicks. Three clusters were obtained based on peak frequency (129, 137, and 173 kHz) and 3 dB bandwidth (8, 6, and 5 kHz). The 428 buzz clicks were analyzed separately. They consisted of clicks emitted with a median inter-click interval of 3.5 ms, peak frequency at 131 kHz, 3 dB bandwidth of 9 kHz, 10 dB bandwidth of 18 kHz, and duration of 56 μs. Buzz clicks were significantly shorter and with a lower peak frequency and a broader bandwidth than most of the regular clicks. This study provided the first description of different echolocation signals, including on- and off-axis signals, recorded from Commerson's dolphins in the wild, most likely as a result of animals at several distances and orientations to the recording device. This information could be useful while doing passive acoustic monitoring.
authors.affiliation: Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, and Instituto de Física de Buenos Aires, Centro Nacional de Investigaciones Científicas y Técnicas, Pabellón I, Ciudad Universitaria, 1428, Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: M Vanesa
authors.initials: MV
authors.lastname: Reyes Reyes
authors.affiliation: Fundación Cethus, Gdor Luis Monteverde 3695 (B1636AEM), Olivos, Provincia de Buenos Aires, Argentina.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Iñíguez
authors.affiliation: Fundación Cethus, Gdor Luis Monteverde 3695 (B1636AEM), Olivos, Provincia de Buenos Aires, Argentina.
authors.forename: Marta
authors.initials: M
authors.lastname: Hevia
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive 0205, La Jolla, California 92093-0205, USA.
authors.forename: John A
authors.initials: JA
authors.lastname: Hildebrand
authors.affiliation: Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive 0205, La Jolla, California 92093-0205, USA.
authors.forename: Mariana L
authors.initials: ML
authors.lastname: Melcón
mesh_terms: D000367:Age Factors; D000465:Algorithms; D000818:Animals; D061006:Bays; D016000:Cluster Analysis; D004289:Dolphins / Q000502:physiology*; D004455:Echolocation; D008685:Meteorological Concepts; D012621:Seasons; D013018:Sound Spectrography