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Abstract: 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 0.1–1kHz linear sweep (150dBrms re 1μPa). 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. [Copyright &y& Elsevier]

Simple Summary: To date there is not much information regard the role that sounds may play in the life of elasmobranchs. This gains particular importance if we consider the current understanding about noise pollution at sea. In fact, in the past few years, the effects of anthropogenic noise on marine fauna have received increasing attentions considering the plethora of repercussions deriving from the expansion of this type of pollution. Here, we exposed small-spotted catshark specimens kept in an aquarium, to different acoustic conditions to analyse the possible changes in swimming behaviour. Four different acoustic conditions consisted of biological sounds and anthropogenic noises. Moreover, the amplitude levels were differentiated among them, to analyse the effects caused by different signal-to-noise ratios. The results highlighted both a tendency of the animals to increase the overall time spent swimming and to avoid the noisiest section of the aquarium when subjected to higher amplitude levels of noise. Despite the growing interest in human-made noise effects on marine wildlife, few studies have investigated the potential role of underwater noise on elasmobranch species. In this study, twelve specimens of small-spotted catshark (Scyliorhinus canicula) were exposed to biological and anthropogenic sounds in order to assess their behavioural changes in response to prey acoustic stimuli and to different amplitude levels of shipping noise. The sharks, individually held in aquariums, were exposed to four experimental acoustic conditions characterized by different spectral (Hz) components and amplitude (dB re 1 µPa) levels. The swimming behaviour and spatial distribution of sharks were observed. The results highlighted significant differences in swimming time and in the spatial use of the aquarium among the experimental conditions. When the amplitude levels of biological sources were higher than those of anthropogenic sources, the sharks' swimming behaviour was concentrated in the bottom sections of the aquarium; when the amplitude levels of anthropogenic sources were higher than biological ones, the specimens increased the time spent swimming. Moreover, their spatial distribution highlighted a tendency to occupy the least noisy sections of the aquarium. In conclusion, this study highlighted that anthropogenic noise is able to affect behaviour of catshark specimens and the impact depends on acoustic amplitude levels. [ABSTRACT FROM AUTHOR]