Individually distinctive parameters in the upcall of the North Atlantic right whale (Eubalaena glacialis)

Abstract

According to the source-filter hypothesis proposed for human speech, physical attributes of the vocal production mechanism combine independently to result in individually distinctive vocalizations. In the case of stereotyped calls with all individuals producing a similar frequency contour, the filtering of the signal resulting from the shape and size of the vocal tract may be more likely to contain individually distinctive information than parameters measured from the fundamental frequency resulting from the vibrating source. However, the formant structure resulting from such filtering has been historically undervalued in the majority of studies addressing individual distinctiveness in non-human species. The upcall of the North Atlantic right whale (Eubalaena glacialis) is characterized as a stereotyped contact call, and visual inspection of upcall spectrograms confirms presence of a robust formant structure. Here we present preliminary results testing individual distinctiveness of upcalls recorded from archival, suction cup mounted tags (Dtags). Parameters measured from the fundamental frequency contours as well as the formant structure of the calls are used in assigning upcalls to individual whales. These results provide a baseline for further development of acoustic detection techniques that could be used to noninvasively track movements of individual whales across habitats.