The social signaling behavior of humpback whales on the Hawaiian breeding grounds investigated using acoustic tags

• Autor(a) principal: Carvalho, Jéssica
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.1/18996
• topic: Humpback whale; Social calls; Vocal communication; Group composition; Acoustic tag; Hawaiian Islands; Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais

Humpback whales (Megaptera novaeangliae) are one of the most social of all baleen whale species. The song produced by males has captivated audiences, both scientific and public alike. Despite extensive research into humpback whale songs, gaps remain in the understanding of humpback whale communication. These gaps are particularly evident concerning humpback whale non-song social vocalizations. This study expands upon the current knowledge of non-song social call use and function by comparing call type, features, and temporal parameters across humpback whale groups of three different compositions: dyads, escorted mother-calf pairs, and competition groups (comprised of a single female and two or more competing males). Recordings were collected from 12 deployments of AcousondeTM acoustic and data logging tags on whales off Maui, Hawaii during the winter breeding seasons of 2019-2021. Individual social calls were selected based on visual and aural inspection of spectrograms using Raven Pro 1.6 software, with a total of 1,102 calls chosen throughout the 69.5 hours of acoustic recordings. Of these calls, 52.2% occurred in competition groups, 34.9% in escorted mother-calf pairs, and 12.9% in dyads, although the difference in call rate (calls/hr) was not statistically significant across groups (Chi-square, p = 0.0671). Commonly used call types varied across groups, but all group compositions often observed four call types (knock, squeak, bellow, moo). Though social calls were shared across groups, the temporal parameters and frequencies of the calls produced varied significantly (Kruskal-Wallis, p<1e-07). Our study provides new insights into humpback whale vocal communication behavior in the Hawaiian Islands breeding grounds, particularly concerning three main social groups whose non-song vocal communications have been understudied.