The effect of boat noise on the behaviour of bluefin tuna Thunnus thynnus was investigated\ud in the Egadi Islands, Sicily, during spring 2005 using a fixed tuna trap set near shipping routes.\ud Tuna behaviour was observed when exposed to both natural ambient sound and sound generated by\ud hydrofoil passenger ferries, small boats and large car ferries. Acoustical and behavioural analyses\ud were conducted with and without extraneous sound to define a list of behavioural categories. Each\ud vessel produced different engine sounds with regard to their composition and bandwidth, and all\ud were distinctly different from ambient sound levels. In the absence of boat noise, tuna assumed a concentrated\ud coordinated school structure with unidirectional swimming and without a precise shape.\ud When a car ferry approached, tuna changed swimming direction and increased their vertical movement\ud toward surface or bottom; the school exhibited an unconcentrated structure and uncoordinated\ud swimming behaviour. Hydrofoils appeared to elicit a similar response, but for shorter periods. Agonistic\ud behaviour was more evident when exposed to sounds from outboard motors of small boats. This\ud study showed that local noise pollution generated by boats produced behavioural deviations in tuna\ud schools. Schooling enhances tuna homing accuracy during their spawning migration, and an alteration\ud in schooling behaviour can affect the accuracy of their migration to spawning and feeding\ud grounds

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.

No abstract

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

No abstract

Fouling species richness, abundance and composition and biomass were chosen as the descriptors of e¡ect of fish farm organic enrichment. The study was carried out in September 2004 inthe Gulf of Castellammare\ud (South Tyrrhenian, Mediterranean). The fouling species were sampled from plastic buoys spaced throughout the study area both up- [UP] and down-stream [DOWN]. The results showed that fouling community responded to the chronic input of allochthonous organic matter experiencing local changes more or less signi¢cantly with regard to abundance, species composition and general community diversity. Upper fouling would work as a filter naturally opposed by environment resistance assimilating and facilitating the accommodation of most organic surplus. In highly hydrodynamic and suffciently deep systems, the transport of organic particles produced from farms would have an eject along the horizontal axis rather than along the vertical axis, involving upper located benthic organisms rather than sedimentary benthic organisms

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.

There is some evidence that the presence of Tursiops truncatus in fishing areas represents a real economic threat to fishermen due the dolphin feeding on the entangled fish, damaging the nets and reducing the fish catch. We have carried out experiments to assess the efficiency of a pinger in decreasing the interaction between the dolphins and fishing nets, in a fishing area off the coast of southern Italy, where Tursiops truncatus is frequently observed to interact with bottom gill nets. Two identical monofilament bottom gill nets (900 m long), one equipped with pingers and the other without, were used to measure the effect of these pingers on the abundance of the catch and net damage. For each haul (58 in total), data on dolphin sightings near the nets, damage judged to have been done by dolphins, weight and species composition of the catch were collected. All damage to the nets were recorded at the end of each haul. Dolphins in the fishing area were sighted 11 times out of 29 fishing activities (38%). The net equipped with pingers contained 28% more fish (biomass) than the net without pingers (t test, P \ 0.04) and was less damaged (-31%, t test, P \ 0.01). To assess whether the efficacy of these pingers remain constant over long period, long-term experiments should be carried out.