Whistle characteristics of newly defined species, the Burrunan dolphin (Tursiops australis), in coastal Victorian waters in Australia

A newly defined species, the Burrunan dolphin (Tursiops australis), was described in 2011 by Charlton-Robb et al., and is endemic to southern and south-eastern Australian coastal waters. This species' distribution is characterized by small, isolated, and genetically distinct populations. With only two known populations in Victoria, the species is now listed as “Threatened” under the Victorian Flora and Fauna Guarantee Act. Describing and quantifying the vocal repertoire of a species is critical for subsequent analysis of signal functionality, geographic variation, social relevance, and identifying threats associated with anthropogenic noise. Here, we present the first quantitative analysis of whistle characteristics for the species, undertaken on these endemic Victorian populations. Vocalizations of T. australis were recorded during population based surveys in 2007 and 2014 across the Gippsland Lakes and Port Phillip Bay, Victoria. Acoustic parameters of whistles were measured including minimum frequency (fmin), maximum frequency (fmax), start frequency (sf), end frequency (ef), delta frequency (df= fmax-fmin), duration, number of extrema, number of inflection points, and number of steps. We review and compare T. australis whistle features to the two other bottlenose dolphins, T. truncatus and T. aduncus, to assess the similarity and/or differences between the sounds of the three species of bottlenose dolphins.