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This study examined the effects of three different acoustic stimuli on the behaviour of the European spiny lobster, Palinurus elephas (Fabricius, 1787). Twenty male and 20 female lobsters were exposed to: a low-frequency linear sweep tone (0.1-20 kHz), a high-frequency linear sweep tone (20-80 kHz), conspecific sounds (rasp: train of wideband pulses), and no sound stimulation (control). After a habituation period, lobsters were audio-video recorded for 30 min. Tail flipping, sound emissions, distance moved, mobility, velocity and movement were recorded. Differences between the males and females in the rasp playback condition were observed, with the females having highest values of the behaviours under study. Moreover, when analysing the male and female combined data we found that exposure to synthetic stimuli did not produce any significant variations. Finally, it can be assumed that there is: a capacity for rasp sound perception, and a significant role for these pulses in the intraspecific communication of P. elephas.Key words. -European spiny lobster, noise exposure, behavioural responses, conspecific communication RIASSUNTO Il presente studio ha esaminato gli effetti di tre differenti stimoli acustici sul comportamento dell'aragosta Europea, Palinurus elephas (Fabricius, 1787). Venti esemplari maschi e 20 femmine sono stati esposti ad uno sweep tone lineare a bassa frequenza (0.1-20 kHz), uno sweep tone lineare ad alta frequenza (20-80 kHz), suoni di conspecifici (rasp: treno di impulsi a banda larga), e a nessuna stimolazione acustica (controllo). Dopo un periodo di acclimatamento, le aragoste sono state sottoposte a monitoraggio audio-video per 30 minuti. Sono stati registrati i seguenti eventi e stati comportamentali: tail flip, emissioni acustiche, distanza mossa, mobilità, velocità e movimento.Nella condizione rasp sono state osservate differenze tra maschi e femmine e quest'ultime hanno mostrato i valori più alti dei comportamenti oggetto di indagine. Ulteriormente, analizzando i dati cumulativi di maschi e femmine, si è osservato che l'esposizione a stimoli sintetici non ha prodotto nessuna significativa variazione comportamentale. Infine, è possibile concludere che le aragoste sono in grado di percepire i rasp e che questi impulsi giocano un ruolo significativo nella comunicazione intraspecifica di P. elephas.

In this study the description of underwater vocal repertoire of bearded seal in Svalbard (Norway) was extended. Two autonomous passive acoustic recorders were deployed for one year (August 2014-July 2015) in the inner and outer parts of the Kongsfjorden, and 1728 h were recorded and 17 220 vocalizations were found. Nine different vocalization classes were identified and characterized using ten acoustic parameters. The calls showed heterogeneous spectral features, but share the descending trend of frequency modulation. The different classes emerged were discriminated primarily by bandwidth and duration, and then by minimum frequency, central frequency, and maximum frequency in this order. This study represents a step forward to improve the understanding of the acoustic behaviour and the social function of these calls, and identified long passive acoustic monitoring as an effective method to assess vocal complexity and the ecology of marine species producing sounds.