IL COMPORTAMENTO ACUSTICO DEI TURSIOPI IN LIGURIA: USO DEI FISCHI FIRMA IN RELAZIONE AL CONTESTO COMPORTAMENTALE E ALLA COMPOSIZIONE SOCIALE

THE ACOUSTIC BEHAVIOUR OF BOTTLENOSE DOLPHINS IN LIGURIA: USE OF SIGNATURE WHISTLES IN RELATION TO BEHAVIOURAL CONTEXT AND SOCIAL COMPOSITION

Abstract

Bottlenose dolphins (Tursiops truncatus) emit frequency-modulated whistles, especially employed in intraspecific communication. In the Pelagos Sanctuary, the acoustic behaviour of free-ranging bottlenose dolphins remains understudied, especially concerning the anthropogenic and social factors influencing whistle emission. In this study, we recorded the whistles of free-ranging common bottlenose dolphins in the shelf waters between Genoa and La Spezia (eastern Liguria, Italy) from May to October 2023. We analysed 1230 whistles, identified signature whistles (SW) – signals broadcasting the emitter identity - and extracted spectrotemporal parameters using Praat and PAMGUARD. Our results showed a greater production of SW and multiloop when calves were present in the group, especially during feeding behind trawlers. These findings support the pivotal coordinating role played by SW in the mother-calf relationship, especially in crowded and dynamic contexts. Moreover, our results cautiously suggest the existence of potential group whistles in the studied unit, highlighting the need for further research.