The study of marine soundscapes is an emerging field of research that contributes important information about biological compositions and environmental conditions. The seasonal and circadian soundscape trends of a marine protected area (MPA) in the Mediterranean Sea have been studied for one year using an autonomous acoustic recorder. Frequencies less than 1 kHz are dominated by noise generated by waves and are louder during the winter; conversely, higher frequencies (4–96 kHz) are dominated by snapping shrimp, which increase their acoustic activity at night during the summer. Fish choruses, below 2 kHz, characterize the soundscape at sunset during the summer. Because there are 13 vessel passages per hour on average, causing acoustic interference with fish choruses 46% of the time, this MPA cannot be considered to be protected from noise. On the basis of the high seasonal variability of the soundscape components, this study proposes a one-year acoustic monitoring protocol using the soundscape methodology approach and discusses the concept of MPA size.

This study examined the effects of boat noise on the behavioural and biochemical parameters of the Mediterranean spiny lobster (Palinurus elephas). The experiment was conducted in a tank equipped with a video and audio recording system. 18 experimental trials, assigned to boat noise and control conditions, were performed using lobsters in single and group of 4 specimens. After a 1h habituation period, we audio- and video-recorded the lobsters for 1h. During the experimental phase, the animals assigned to the boat groups were exposed to boat noise pollution (a random sequence of boat noises). Exposure to the noise produced significant variations in locomotor behaviours and haemolymphatic parameters. Our results indicate that the lobsters exposed to boat noises increased significantly their locomotor activities and haemolymphatic bioindicator of stressful conditions such as glucose, total proteins, Hsp70 expression and THC when tested both singly and in groups.

The acoustic behaviour of the European spiny lobster Palinurus elephas (Fabricius, 1787) was examined in the absence or presence of predators or conspecifics. Observations were conducted in a tank equipped with digital video and acoustic monitoring and recording systems using 25 adult lobsters and 5 common octopuses Octopus vulgaris. Single lobsters or groups of 4 lobsters were studied for 2 h. These were left alone during the first hour and exposed to a single specimen of the common octopus during the second hour. The lobsters' signals were acoustically analysed. Signal duration, number of pulses per signal, pulse rate, bandwidth, peak intensity, and peak frequency were measured. Single lobsters emitted a higher number of signals than lobsters belonging to a group. The signal (rasp) was audible to humans only in the presence of a predator and was always associated with specific behavioural events. In the absence of a predator, the lobsters produced ultrasound signals (screech) having lower duration, number of pulses per signal, bandwidth, and peak intensity and higher pulse rate and peak frequency. Audible rasps were produced in an anti-predator context, whereas the ultrasound screeches were also emitted under non-stressful conditions. Thus, these signals may play a role in intraspecific communication. KEY WORDS: Acoustic behaviour · Palinurus elephas · Intraspecific communication · Antipredator behaviourResale or republication not permitted without written consent of the publisher OPEN PEN ACCESS CCESS

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An understanding of the population dynamics and social organization of cetaceans is essential to manage the influence of anthropogenic activities. In this study, the population size, site fidelity and social interactions of bottlenose dolphins in the Strait of Sicily (Italy) were investigated to provide recommendations for their conservation. Mark‐recapture analysis was based on the encounter histories of 103 marked dolphins from 2004 to 2015. The POPAN formulation of the Jolly–Seber model in MARK software was used to estimate the size of the super‐population. Site fidelity and social organization were estimated for individuals re‐sighted ≥3 times. The estimated population size was 140 (SE = 15.75; 95% CI = 106–164). Dolphins had low site fidelity, and both adults and sub‐adults move outside the study area. Females with calves used the area longer than other individuals. Based on our results, dolphins’ home range likely extended beyond the study area. The mean value of the Half‐Weight Association Index was low and the preferred association was by casual acquaintance. However, we found a distinct aggregation of post‐parturition females during the final 2 years of the study. Therefore, the pattern of association was apparently a response to an ecological requirement, which was the possibility to breed in high productivity waters. Whether these individuals are part of a larger pelagic population is unknown; however, we can conclude that the management of only coastal waters is insufficient for the conservation of dolphins in the Strait of Sicily.

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The aim of the present work was to reveal the behaviour of the European spiny lobster Palinurus elephas (Fabricius, 1787) during encounters with predators. The study was conducted in a tank, exposing lobsters individually or in groups to a single specimen of the European conger eel or the common octopus. The behaviours of the lobsters, their sounds and the behaviours of the predators were recorded using a digital audio-video underwater acquisition system and analysed. A behavioural event not found in literature, dubbed 'Alert' by the authors, was described. The results showed that the most recurrent events were Alert, Point and Whip, which have the function of controlling the predator with the antennae, while maintaining the predator-prey distance. Moreover, a strong association between Tail Flip and Lunge (events that were stimulated in response to an imminent danger to life) with the sounds emitted by lobsters was observed. Significantly more sounds were emitted during the tests with single lobsters compared to grouped lobsters. As a result of the present study, the European conger eel may also be considered a potential natural predator of the European spiny lobster.

Biphonic signals are non-linear phenomena occurring in the repertoire of several animal groups and widespread across mammalian species. Although the mechanism of production is unclear, an adaptive meaning was suggested by their communication function, such as group or individual recognition. We document the rare recording event of a biphonic whistle emitted within a freeranging population of bottlenose dolphins in the waters of southwestern Sicily, Italy. The whistle was recorded in three different years, always when a photo-identified individual was present. A quantitative description of the signal is provided. The signal presents some unique characteristics in its frequency modulation pattern which is stable for a long period. Furthermore, the synchronized beginning of the two fundamental frequencies, the signal repetition within few seconds and in its emission in freely interacting contexts suggest that biphonation is neither temporary nor involuntary. Also, we propose that biphonation can be produced via multiple mechanisms in bottlenose dolphins and that Non Linear Phenomena could represent natural recognizing marks that play a role in communication between bottlenose dolphins.