Francesco Filiciotto

Impact of an acoustic stimulus on the motility and blood parameters of European sea bass (Dicentrarchus labrax L.) and gilthead sea bream (Sparus aurata L.)

The physiological responses of fish to underwater noise are poorly understood and further information is needed to evaluate any possible negative effects of sound exposure. We exposed European sea bass and gilthead sea bream to a 0.1-1 kHz linear sweep (150 dB(rms) re 1 microPa). This band frequency is perceptible by many species of fish and is mainly produced by vessel traffic. We assessed the noise-induced motility reaction (analysing the movements) and the haematological responses (measuring blood glucose and lactate, and haematocrit levels). The noise exposure produced a significant increase in motility as well as an increase in lactate and haematocrit levels in sea bream and sea bass. A significant decrease of glucose was only observed in sea bream. A linear correlation between blood parameters and motility in fish exposed to the noise was observed. The acoustic stimulus produced intense muscle activity.

Behavioural and biochemical stress responses of Palinurus elephas after exposure to boat noise pollution in tank.

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.

Physiological and agonistic behavioural response of Procambarus clarkii to an acoustic stimulus

SUMMARY This study examined the effects of an acoustic stimulus on the haemolymph and agonistic behaviour of the red swamp crayfish, Procambarus clarkii. The experiment was conducted in a tank equipped with a video recording system using six groups (three control and three test groups) of five adult crayfish (30 specimens in total). After 1 h of habituation, the behaviour of the crayfish was monitored for 2 h. During the second hour, the animals in the test groups were exposed to a linear sweep (frequency range 0.1–25 kHz; peak amplitude 148 dBrms re. 1 μPa at 12 kHz) acoustic stimulus for 30 min. Exposure to the noise produced significant variations in haemato-immunological parameters as well as a reduction in agonistic behaviour.

Automatic analysis to assess haematological parameters in farmed gilthead sea bream (Sparus aurata Linnaeus, 1758)

The haematological parameters (RBC, Hb, PCV, WBC, TC, MCV, MCH, and MCHC) in farmed gilthead sea bream (Sparus aurata) were measured using an automatic method. We then compared the outcomes using the traditional manual method. After blood collection (T0), all samples were immediately analyzed using both the manual and automatic methods. The samples were successively divided into five different aliquots and stored at +4°C to evaluate the effect of the storage time on haematological parameters, measured with the automatic method, at 6, 24, 48, 72, and 96 h after collection. Paired t-tests were applied between the values obtained at T0 with the manual and automatic methods and no statistical difference was observed. One-way repeated measures analysis of variance (ANOVA) showed that parameters measured with the automatic system were significantly affected by the storage time (p < 0.0001). These results provide an innovative automatic method for the determination of haematological parameters in sea bream and suggest that the haematological profile can be accurately assessed within 6 h from blood collection.

Stranded cetaceans as indicators of mercury pollution in the Mediterranean Sea

Abstract Concentrations of Hg were determined in tissues (muscle, heart, kidney, lung and liver) of two cetacean species (Stenella coeruleoalba and Tursiops truncatus) stranded along the Italian coasts during the period 2000–2009 and compared with those previously reported by other authors from different areas of the Mediterranean basin. The highest concentrations of Hg were found in liver samples of both species (8.4-1752 mg·kg−1 dry weight for S. coeruleoalba and 9.6-1404 mg·kg−1 d.w. for T. truncatus). Statistically significant dissimilarities of Hg concentrations were recorded in muscle and liver tissues of S. coeruleoalba stranded in different geographical areas of the Mediterranean Sea as apparent direct response to uneven impacts of Hg pollution in the basin. A noteworthy outcome was that cetaceans stranded on the French coasts showed significantly higher levels of Hg contamination than those from other Mediterranean areas while the eastern part of the basin evidences the lowest Hg concentrations in the studied organisms. Moreover, the results of this study tentatively suggest the existence of different sub-populations of the two species in the basin.

The underwater acoustic activities of the red swamp crayfish Procambarus clarkii

This study describes the underwater acoustic behavior of the red swamp crayfish Procambarus clarkii. The study was conducted both in a tank and in the natural environment. The tank was equipped with video and acoustic recording systems. Observations were conducted to identify the underwater acoustic signals produced and their association with behavioral events and the movement status of the animals. In a lake in a natural reserve, a remote acoustic recording station was used to study the circadian underwater acoustic activity of the crayfish and to assess the acoustic features of the signals. The red swamp crayfish produces irregular trains of wide-band pulses (duration 0.4 ms, SPL(PK) 128 dB re 1 μPa, peak frequency 28 kHz, bandwidth(RMS) 20 kHz). The production of signals is positively related to intraspecific interactions (encounter/approach, fighting and successive Tail Flips). In the natural environment, acoustic activity is almost absent during the day, increases abruptly at sunset and continues until dawn. This study reveals the previously unknown underwater acoustic signals of Procambarus clarkii and the potential of passive acoustic methods to monitor the presence, the abundance and the behavioral activities of this invasive species.

Temporal patterns in the soundscape of the shallow waters of a Mediterranean marine protected area.

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.

Biphonic calls as signature whistles in a free-ranging bottlenose dolphin

Biphonic signals are nonlinear phenomena (NLPs) 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 free-ranging population of bottlenose dolphins in the waters of south-western Sicily, Italy. The whistle was recorded in 2 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 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 NLPs could represent natural recognizing marks that play a role in communication between bottlenose dolphins.

Behavioural responses of the European spiny lobster, Palinurus elephas(Fabricius, 1787), to conspecific and synthetic sounds

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.

Depredation of striped dolphin on squid fishery and behavioural responses to interactive pinger.

The depredation of dolphins on some artisanal fisheries in the Mediterranean Sea is the major source of economic loss. This study aims to reveal the behavior of striped dolphin during interaction with flying squid fishery equipped with interactive pinger in the Ionian Sea (southern Italy). A four channel acoustics acquisition system was used during fishing hauls to record the clicks and to localize the positions of dolphins through the time delay of arrival method. The preliminary analysis shows that dolphins approached the artificial light, used for attract the squids, diving further on 100 m below the fishing boat. The number and the power of dolphins’ clicks decreased after the signals emitted by the interactive pinger. The distances of dolphins from fishing boat do not seem change significantly before and after pinger emissions. Although the efficiency of DDD pingers to decrease the depredation level was demonstrated in some study, the functioning mechanism is still unknown. Our data could indicate th...