Gianni Pavan

Sound production during courtship and spawning among freshwater gobiids (pisces, gobiidae)

In this paper the breeding sound production among gobiids is reviewed. Results of recent comparative studies on both pre‐spawning (courtship) and spawning sound production in the three italian freshwater gobiids are reported. A significant production of sounds associated to mating was discovered in two of these species. Furthermore, the quantification of acoustic behaviour across the spawning period (i.e., from the beginning of oviposition until the departure of the female from the males nest) revealed a pattern of spawning sound production similar in the two species.

Spawning vocalizations in male freshwater gobiids (Pisces, Gobiidae)

SynopsisMales of two freshwater Italian gobies, the common goby, Padogobius martensii and the panzarolo goby, Knipowitschia punctatissima, emit trains of low-frequency pulses, i.e. ‘drumming’ sounds, in the presence of a ripe female in the nest. In P, martensii the drumming sound is usually followed by a tonal sound (complex sound). Examination of the pulse structure suggests that these sounds are produced by muscles acting on the swimbladder. Both species exhibited high emission rates of spawning sounds, especially before the beginning of oviposition. Moreover, spawning sound production ceased only after the female abandoned the nest, which always occurred at the end of oviposition. This is the first study reporting the production among fishes of distinct sounds during protracted spawning. Unlike sounds produced just before mating by fishes with planktonic or demersal zygotes, the spawning sound production of these gobies does not function to coordinate mating events in the nest. The presence of a two-part vocalization by male P. martensii even suggests a functional dichotomy of spawning sounds in this species.

Time patterns of sperm whale codas recorded in the Mediterranean Sea 1985–1996

A distinctive vocalization of the sperm whale, Physeter macrocephalus (=P. catodon), is the coda: a short click sequence with a distinctive stereotyped time pattern [Watkins and Schevill, J. Acoust. Soc. Am. 62, 1485–1490 ()]. Coda repertoires have been found to vary both geographically and with group affiliation [Weilgart and Whitehead, Behav. Ecol. Sociobiol. 40, 277–285 ()]. In this work, the click timings and repetition patterns of sperm whale codas recorded in the Mediterranean Sea are characterized statistically, and the context in which the codas occurred are also taken into consideration. A total of 138 codas were recorded in the central Mediterranean in the years 1985–1996 by several research groups using a number of different detection instruments, including stationary and towed hydrophones, sonobuoys and passive sonars. Nearly all (134) of the recorded codas share the same “3+1” (/// /) click pattern. Coda durations ranged from 456 to 1280 ms, with an average duration of 908 ms and a standard deviation of 176 ms. Most of the codas (a total of 117) belonged to 20 coda series. Each series was produced by an individual, in most cases by a mature male in a small group, and consisted of between 2 and 16 codas, emitted in one or more “bursts” of 1 to 13 codas spaced fairly regularly in time. The mean number of codas in a burst was 3.46, and the standard deviation was 2.65. The time interval ratios within a coda are parameterized by the coda duration and by the first two interclick intervals normalized by coda duration. These three parameters remained highly stable within each coda series, with coefficients of variation within the series averaging less than 5%. The interval ratios varied somewhat across the data sets, but were highly stable over 8 of the 11 data sets, which span 11 years and widely dispersed geographic locations. Somewhat different interval ratios were observed in the other three data sets; in one of these data sets, the variant codas were produced by a young whale. Two sets of presumed sperm whale codas recorded in 1996 had 5- and 6-click patterns; the observation of these new patterns suggests that sperm whale codas in the Mediterranean may have more variations than previously believed.

Individually distinct hooting in male Pygmy Owls Glaucidium passerinum: a multivariate approach

During a study of territorial behaviour of the Pygmy Owl in NE Italy we used spectrographic analyses of recorded territorial calls to distinguish individual males. Two temporal parameters and the mean fundamental frequency of the song were selected and measured. All parameters of calls varied significantly within the population and discriminant analysis correctly classified 84.6% of the individual Pygmy Owls. Most individuals differed from each other with respect to the three selected parameters.

The importance of breeding vocalizations for mate attraction in a freshwater goby with a composite sound repertoire

Male gobies, Padogobius martensii, emit ‘tonal’ sounds during courtship, and ‘drumming’ and ‘complex’ sounds during spawning. The complex sound is a two-part vocalization consisting of a drumming sound followed without pause by a tonal sound. In the laboratory, the playback of both the tonal sound and the drumming sound to ripe females P. martensii determined oriented approaching and increased the time spent by the subject within the loudspeaker area. Response levels to the sound playback (drumming sounds) tended to be correlated with degree of ripeness of the female. Functional aspects of the female response to both types of acoustic stimuli are discussed.

Cetacean strandings in Italy: an unusual mortality event along the Tyrrhenian Sea coast in 2013

An unusual mortality event involving cetaceans, mainly striped dolphins Stenella coeruleoalba (Meyen, 1833), occurred along the Tyrrhenian Sea coast of Italy during the first 3 mo of 2013. Based on post-mortem analyses carried out according to body condition on 66 dolphins (54% of stranded animals), several hypotheses to explain the causes of this mortality event were proposed. Although no definitive conclusions can be drawn, dolphin morbillivirus was deemed the most likely cause, although other infectious agents (including Photobacterium damselae damselae and herpesvirus) or environmental factors may also have contributed to this recent mortality event.

NEMO-SN1 Abyssal Cabled Observatory in the Western Ionian Sea

The NEutrino Mediterranean Observatory-Submarine Network 1 (NEMO-SN1) seafloor observatory is located in the central Mediterranean Sea, Western Ionian Sea, off Eastern Sicily (Southern Italy) at 2100-m water depth, 25 km from the harbor of the city of Catania. It is a prototype of a cabled deep-sea multiparameter observatory and the first one operating with real-time data transmission in Europe since 2005. NEMO-SN1 is also the first-established node of the European Multidisciplinary Seafloor Observatory (EMSO), one of the incoming European large-scale research infrastructures included in the Roadmap of the European Strategy Forum on Research Infrastructures (ESFRI) since 2006. EMSO will specifically address long-term monitoring of environmental processes related to marine ecosystems, climate change, and geohazards. NEMO-SN1 has been deployed and developed over the last decade thanks to Italian funding and to the European Commission (EC) project European Seas Observatory NETwork-Network of Excellence (ESONET-NoE, 2007-2011) that funded the Listening to the Deep Ocean-Demonstration Mission (LIDO-DM) and a technological interoperability test (http://www.esonet-emso.org). NEMO-SN1 is performing geophysical and environmental long-term monitoring by acquiring seismological, geomagnetic, gravimetric, accelerometric, physico-oceanographic, hydroacoustic, and bioacoustic measurements. Scientific objectives include studying seismic signals, tsunami generation and warnings, its hydroacoustic precursors, and ambient noise characterization in terms of marine mammal sounds, environmental and anthropogenic sources. NEMO-SN1 is also an important test site for the construction of the Kilometre-Cube Underwater Neutrino Telescope (KM3NeT), another large-scale research infrastructure included in the ESFRI Roadmap based on a large volume neutrino telescope. The description of the observatory and its most recent implementations is presented. On June 9, 2012, NEMO-SN1 was successfully deployed and is working in real time.

The response of the male freshwater goby to natural and synthetic male courtship sound playback following exposure to different female sexual stimuli

Among teleosts, field and laboratory experiments have shown the playback of male courtship sounds often elicits competitive courtship and sound emission in the territorial male. However, the importance of female stimulation for the male response to the sound is poorly understood. In this study, playback experiments with the freshwater goby, Padogobius martensii, examined the response of resident males (i.e. males individually housed within laboratory tanks for at least 5 days) to natural and synthetic male courtship sounds after exposure to chemical or visual stimuli from a ripe female. All playback tests consisted of one experimental (sound playback) and two control treatments, all of equal duration. Three experiments were conducted on a first group of 12 males using natural courtship sounds. Experiment 1 consisted of playing back the sound to a male that had not exposed to female stimulation for at least 24 hr. The same male was exposed to the “female pheromone” by dropping a few cm3 of female holding water into the males tank, just prior to playback (Experiment 2), or to the view of a live ripe female in a close-by tank, during playback (Experiment 3). The sound playback failed to elicit positive responses by males not exposed to female stimuli (Experiment 1), and did not increase courtship activity of the male in visual contact with the female (Experiment 3). However, it increased swimming activity and facilitated courtship and sound production in the male after an increase in sexual arousal by prior chemical stimulation (Experiment 2). In Experiment 4, the synthetic version of the courtship sound and one deprived of pulse-rate modulation and harmonic content (pure tone) were played back to 10 resident males following prior chemical stimulation. The synthetic courtship sound, but not the pure tone, was effective in eliciting positive responses by the sexually aroused male. Functional implications of the responses to the courtship sound for the territorial male are discussed. The results are relevant to the understanding of the role of sound communication and interception among gobies and to develop playback experiments in the field.

Annual acoustic presence of fin whale (Balaenoptera physalus) offshore Eastern Sicily, central Mediterranean Sea

In recent years, an increasing number of surveys have definitively confirmed the seasonal presence of fin whales (Balaenoptera physalus) in highly productive regions of the Mediterranean Sea. Despite this, very little is yet known about the routes that the species seasonally follows within the Mediterranean basin and, particularly, in the Ionian area. The present study assesses for the first time fin whale acoustic presence offshore Eastern Sicily (Ionian Sea), throughout the processing of about 10 months of continuous acoustic monitoring. The recording of fin whale vocalizations was made possible by the cabled deep-sea multidisciplinary observatory, “NEMO-SN1”, deployed 25 km off the Catania harbor at a depth of about 2,100 meters. NEMO-SN1 is an operational node of the European Multidisciplinary Seafloor and water-column Observatory (EMSO) Research Infrastructure. The observatory was equipped with a low-frequency hydrophone (bandwidth: 0.05 Hz–1 kHz, sampling rate: 2 kHz) which continuously acquired data from July 2012 to May 2013. About 7,200 hours of acoustic data were analyzed by means of spectrogram display. Calls with the typical structure and patterns associated to the Mediterranean fin whale population were identified and monitored in the area for the first time. Furthermore, a background noise analysis within the fin whale communication frequency band (17.9–22.5 Hz) was conducted to investigate possible detection-masking effects. The study confirms the hypothesis that fin whales are present in the Ionian Sea throughout all seasons, with peaks in call detection rate during spring and summer months. The analysis also demonstrates that calls were more frequently detected in low background noise conditions. Further analysis will be performed to understand whether observed levels of noise limit the acoustic detection of the fin whales vocalizations, or whether the animals vocalize less in the presence of high background noise.

Bioacoustic research on cetaceans in the Mediterranean Sea

In recent years new impetus has been put into cetacean research in the Mediterranean Sea. From 1988 to 1994 research cruises were organized by our laboratory and the Tethys Research Institute within the seas surrounding the Italian peninsula and islands. Recordings of underwater sounds produced by cetaceans and other ethological and zoogeographical data were collected and analyzed with the use of instruments and techniques mainly developed by the Laboratory of Marine Bioacoustics, which was conceived by the University of Pavia and financed by the Inspectorate of Sea Defence of the Italian Ministry of the Environment. Specific instruments and software packages were developed, including a high‐quality towed array of hydrophones, with its own amplifier and filtering unit, a portable Digital Signal Processing Workstation (DSPW) with real time analysis and file processing capabilities and an Interactive Digital Sound Library (IDSL). Cetacean sounds were recorded in their natural environment from auxiliary sail...