<jats:sec> <jats:title>Background</jats:title> <jats:p>Marine soundscape ... more <jats:sec> <jats:title>Background</jats:title> <jats:p>Marine soundscape is the aggregation of sound sources known as geophony, biophony, and anthrophony. The soundscape analysis, in terms of collection and analysis of acoustic signals, has been proposed as a tool to evaluate the specific features of ecological assemblages and to estimate their acoustic variability over space and time. This study aimed to characterise the Capo Caccia-Isola Piana Marine Protected Area (Italy, Western Mediterranean Sea) soundscape over short temporal (few days) and spatial scales (few km) and to quantify the main anthropogenic and biological components, with a focus on fish biophonies.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Within the MPA, three sites were chosen each in a different protection zone (A for the integral protection, B as the partial protection, and C as the general protection). In each site, two underwater autonomous acoustic recorders were deployed in July 2020 at a depth of about 10 m on rocky bottoms. To characterise the contribution of both biophonies and anthrophonies, sea ambient noise (SAN) levels were measured as sound pressure level (SPL dB re: 1 μ Pa-rms) at eight 1/3 octave bands, centred from 125 Hz to 16 kHz, and biological and anthropogenic sounds were noted. Fish sounds were classified and counted following a catalogue of known fish sounds from the Mediterranean Sea based on the acoustic characteristic of sound types. A contemporary fish visual census had been carried out at the test sites.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>SPL were different by site, time (day <jats:italic>vs</jats:italic>. night), and hour. SPLs bands centred at 125, 250, and 500 Hz were significantly higher in the daytime, due to the high number of boats per minute whose noise dominated the soundscapes. The loudest man-made noise was found in the A zone, followed by the B and the C zone, confirming that MPA current regulations do not provide protection from acoustic pollution. The dominant biological components of the MPA soundscape were the impulsive sounds generated by some invertebrates, snapping shrimps and fish. The vast majority of fish sounds were recorded at the MPA site characterized by the highest sound richness, abundance, and Shannon-Wiener index, coherently with the results of a fish visual census. Moreover, the acoustic monitoring detected a sound associated with a cryptic species (<jats:italic>Ophidion</jats:italic> spp.) never reported in the study area before, further demonstrating the usefulness of passive acoustic monitoring as a complementary technique to species census. This study provides baseline data to detect future changes of the marine soundscapes and some suggestions to reduce the impact of noise on marine biodiversity.</jats:p> </jats:sec>
INTRODUCTION C.I.B.R.A. is a research group whose main interest is in the study of underwater sou... more INTRODUCTION C.I.B.R.A. is a research group whose main interest is in the study of underwater sounds related to marine mammals and in the development of acoustic detection and analysis technologies. The "acoustic " aspect in wide area studies, critical habitat identification and population distribution has become more and more popular. According to our experience it is a difficult task to integrate, in one scheme, acoustic evidences with other data sets like remote sensing or seasonal fluctuations models, and scientists often fail to
Orca (Orcinus orca) is known for complex vocalisation. Their social structure consists of pods an... more Orca (Orcinus orca) is known for complex vocalisation. Their social structure consists of pods and clans sharing unique dialects due to geographic isolation. Sound type repertoires are fundamental for monitoring orca populations and are typically created visually and aurally. An orca pod occurring in the Ligurian Sea (Pelagos Sanctuary) in December 2019 provided a unique occasion for long-term recordings. The numerous data collected with the bottom recorder were analysed with a traditional human-driven inspection to create a repertoire of this pod and to compare it to catalogues from different orca populations (Icelandic and Antarctic) investigating its origins. Automatic signal detection and cross-correlation methods (R package warbleR) were used for the first time in orca studies. We found the Pearson cross-correlation method to be efficient for most pairwise calculations (> 85%) but with false positives. One sound type from our repertoire presented a high positive match (range...
Underwater man-made noise is recognized as a major global pollutant in the 21st Century, and its ... more Underwater man-made noise is recognized as a major global pollutant in the 21st Century, and its reduction has been included in national and international regulations. Despite the fact that many studies have pointed out the ecological impact of noise on marine organisms, few studies have investigated - in a field context - the behavioral response to boat noise in fish. In the present study we measure how Sciaena umbra reacts to boat noise. We found that boat noise: i) increased duration of flight reactions and number of individuals performing them, ii) increased the frequency of hiding behaviors, and iii) did not elicit a change in fish activity level and sound emission. Flights and hiding behavior, usually related to predation risk, were not uniform between individuals and showed a quick recovery after noise exposure. On the basis of these results, potential metabolic, physiological and behavioral consequences are discussed and management recommendations are proposed.
Accurate, rapid and cost-effective fish assemblage monitoring is fundamental for marine protected... more Accurate, rapid and cost-effective fish assemblage monitoring is fundamental for marine protected area (MPA) management as a pivotal tool to verify whether and to what extent MPA conservation objectives have been achieved and to redefine these objectives in the framework of an adaptive management. Recently, there has been a sharp increase in the number of video-based methods to study fish fauna, such as baited remote underwater video (BRUV) systems, that, depending on the objectives of the monitoring, can provide complementary or additional data to the more commonly used underwater visual census (UVC). Even though BRUV systems have been widely used in a wide range of geographic contexts and habitats, their use in the Mediterranean basin is still sporadic and the evaluation of the efficiency of BRUV systems and whether they can be used to complement other techniques needs investigation. Thus, the objective of this study was to assess the performance of a BRUV system in a Mediterranea...
Bottlenose dolphin communication has been studied extensively. Nevertheless, the combined effect ... more Bottlenose dolphin communication has been studied extensively. Nevertheless, the combined effect of several variables on whistle structure has yet to be clearly understood. Here, we investigated the influence of underwater noise, boat presence, behaviour, group size and calf presence on the whistles of a small population of common bottlenose dolphins (Tursiops truncatus). Surface behaviour and acoustic data were collected in Sardinia (Italy-Western Mediterranean Sea) between 2015 and 2017. Whistle frequency parameters (minimum, maximum, start, end frequencies and frequency range), duration, number of inflection points and number of harmonics were correlated with the ambient noise levels recorded prior to the whistle display and to behavioural and social factors by means of GAM models. Whistle frequencies varied as a function of the interaction between noise and boat presence, mainly when the noise increased at lower frequencies. Dolphin whistles also varied according to group size, which was further affected by the presence of calves, and behaviours characterised by high levels of arousal such as feeding. The study provides sufficient evidence to support that multiple factors need to be considered when investigating whistle structure as the species is capable of adopting different strategies depending on environmental, social and behavioural context. Finally, this data indicates that communication within a small population of bottlenose dolphins is vulnerable to acoustic pollution, thereby highlighting the need for further investigation into the effects of different noises on whistle structure, as well as the consistency of patterns across different populations.
Whistles are acoustic signals produced particularly during social interactions. Here, we compare ... more Whistles are acoustic signals produced particularly during social interactions. Here, we compare whistles by bottlenose dolphins from three Mediterranean areas (Croatia, Sicily and Sardinia) to investigate the presence of acoustic divergence and to discuss the possible causes of variability. Whistle parameters differ significantly between populations, but PCA highlights that the majority of variability is due to a limited number of frequency parameters. Cluster and DFA show that the Croatian population is acoustically divergent from the western populations of Sicily and Sardinia. This divergence could be consistent with geographical isolation, and a possible genetic differentiation between populations, and/or an adaptation to the acoustic environment. Moreover, in a comparison of whistle parameters of different Mediterranean populations with those of previously published Atlantic populations, it was revealed that the Sicilian population was acoustically closer to Atlantic population...
ABSTRACT Originally developed wideband acoustic bottom recorders were used. Named RASP -programma... more ABSTRACT Originally developed wideband acoustic bottom recorders were used. Named RASP -programmable underwater acoustic recorder, it is hand deployed from a Zodiac and it is featured with an acoustic release. The recorders have a programmable timer that can follow any desired schedule. The system band-width is 10Hz..48kHz and currently offers 32GB of memory per launch. This study returned 251 hours of non continous acoustic re-cordings over 7 months in 14 deployment sites. The recordings cover day/night periods and almost any weather condition. The files were divided into over 3000 units with 5&amp;#39; duration to create a uniform dataset to be statistically analyzed.
In June 1995, an isolated sperm whale, designated SW0695, was acoustically detected, tracked and ... more In June 1995, an isolated sperm whale, designated SW0695, was acoustically detected, tracked and recorded for more than 7 hours in the Ligurian Sea. It was sighted 8 times at the surface and photographs of its fluke were taken and included in the photo-id catalog we have been collecting since 1994. In September 1996 we detected 7 different whales off Cap Corse (France) and we were able to take photographs of the flukes of three of three whales. Among them, the whale designated SW0996A was identified as the same individual we identified and recorded in 1995. For the first time in the Mediterranean Sea the same sperm whale was photo identified and acoustically recorded two times in consecutive years (15 months lapse). In the first sighting (SW0695), Inter Pulse Intervals (IPI) measured 5.17 ms on average, giving a body length of 11.63 or 12.32 meters depending on the equations used. In the second sighting (SW0696A), the IPIs measured 5.39 ms on average corresponding to a body length o...
The effect of anthropogenic noise on the marine environment is a serious concern for scientists (... more The effect of anthropogenic noise on the marine environment is a serious concern for scientists (Richardson et al., 1995; Nascetti et al., 1997; D'Amico, 1998; Frantzis, 1998; AA.VV, 2003) and has gained the attention of public opinion. To reduce the impact of high power underwater sound sources, Acoustic Risk Mitigation Policies have been drawn up and are currently under implementation. Basically, ARMP are aimed at preserving particularly populated areas and critical habitats, and at reducing or stopping emissions if animals are within a defined distance. Among tested approaches, passive acoustics has shown to be an efficient tool to (a) expand knowledge about marine mammal distribution in space and time (i.e. with surveys), (b) characterise biological and artificial sources, (c) evaluate effects of sound exposure on animals' behaviour, and (d) monitor, detect, locate and track vocalising animals within, or approaching, a sound exposure area. Passive acoustics can continuou...
The ability to detect marine mammals in a specific area is a fundamental requirement for the corr... more The ability to detect marine mammals in a specific area is a fundamental requirement for the correct implementation of mitigation procedures aimed at reducing the impact of high power acoustic sources during either civil or military operations. Passive acoustic monitoring is one of the tools used for this task. In order to be detectable, animals must emit acoustic signals whose time-frequency structure and repetition rate are detectable with the used equipment. Cuvier's beaked whale, Ziphius cavirostris, a critical species when sonar operations are concerned, is difficult to detect. Its acoustic features have been discovered recently by using sophisticated digital recording tags (DTAG) developed by WHOI (Johnson et al., 2004;, but traditional sub-surface detection devices have never been proven reliable. CIBRA developed a high quality wideband towed array with the purpose of detecting Cuvier's beaked whales, and tested it in an area hosting a known population. The experiment was a success, with animals recorded after having been sighted. We thus decided to search other recordings made with equivalent equipment in habitats where beaked whales' sightings had occurred or that were at least compatible with their presence. Clicks matching the Cuvier's beaked whale model were found on two more occasions but with some variation from the known model based on DTAG recordings.
Abstract: CIBRA is a research group whose main interest is in the study of underwater sounds rela... more Abstract: CIBRA is a research group whose main interest is in the study of underwater sounds related to marine mammals and in the development of acoustic detection and analysis technologies. The" acoustic" aspect in wide area studies, critical habitat ...
<jats:sec> <jats:title>Background</jats:title> <jats:p>Marine soundscape ... more <jats:sec> <jats:title>Background</jats:title> <jats:p>Marine soundscape is the aggregation of sound sources known as geophony, biophony, and anthrophony. The soundscape analysis, in terms of collection and analysis of acoustic signals, has been proposed as a tool to evaluate the specific features of ecological assemblages and to estimate their acoustic variability over space and time. This study aimed to characterise the Capo Caccia-Isola Piana Marine Protected Area (Italy, Western Mediterranean Sea) soundscape over short temporal (few days) and spatial scales (few km) and to quantify the main anthropogenic and biological components, with a focus on fish biophonies.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Within the MPA, three sites were chosen each in a different protection zone (A for the integral protection, B as the partial protection, and C as the general protection). In each site, two underwater autonomous acoustic recorders were deployed in July 2020 at a depth of about 10 m on rocky bottoms. To characterise the contribution of both biophonies and anthrophonies, sea ambient noise (SAN) levels were measured as sound pressure level (SPL dB re: 1 μ Pa-rms) at eight 1/3 octave bands, centred from 125 Hz to 16 kHz, and biological and anthropogenic sounds were noted. Fish sounds were classified and counted following a catalogue of known fish sounds from the Mediterranean Sea based on the acoustic characteristic of sound types. A contemporary fish visual census had been carried out at the test sites.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>SPL were different by site, time (day <jats:italic>vs</jats:italic>. night), and hour. SPLs bands centred at 125, 250, and 500 Hz were significantly higher in the daytime, due to the high number of boats per minute whose noise dominated the soundscapes. The loudest man-made noise was found in the A zone, followed by the B and the C zone, confirming that MPA current regulations do not provide protection from acoustic pollution. The dominant biological components of the MPA soundscape were the impulsive sounds generated by some invertebrates, snapping shrimps and fish. The vast majority of fish sounds were recorded at the MPA site characterized by the highest sound richness, abundance, and Shannon-Wiener index, coherently with the results of a fish visual census. Moreover, the acoustic monitoring detected a sound associated with a cryptic species (<jats:italic>Ophidion</jats:italic> spp.) never reported in the study area before, further demonstrating the usefulness of passive acoustic monitoring as a complementary technique to species census. This study provides baseline data to detect future changes of the marine soundscapes and some suggestions to reduce the impact of noise on marine biodiversity.</jats:p> </jats:sec>
INTRODUCTION C.I.B.R.A. is a research group whose main interest is in the study of underwater sou... more INTRODUCTION C.I.B.R.A. is a research group whose main interest is in the study of underwater sounds related to marine mammals and in the development of acoustic detection and analysis technologies. The "acoustic " aspect in wide area studies, critical habitat identification and population distribution has become more and more popular. According to our experience it is a difficult task to integrate, in one scheme, acoustic evidences with other data sets like remote sensing or seasonal fluctuations models, and scientists often fail to
Orca (Orcinus orca) is known for complex vocalisation. Their social structure consists of pods an... more Orca (Orcinus orca) is known for complex vocalisation. Their social structure consists of pods and clans sharing unique dialects due to geographic isolation. Sound type repertoires are fundamental for monitoring orca populations and are typically created visually and aurally. An orca pod occurring in the Ligurian Sea (Pelagos Sanctuary) in December 2019 provided a unique occasion for long-term recordings. The numerous data collected with the bottom recorder were analysed with a traditional human-driven inspection to create a repertoire of this pod and to compare it to catalogues from different orca populations (Icelandic and Antarctic) investigating its origins. Automatic signal detection and cross-correlation methods (R package warbleR) were used for the first time in orca studies. We found the Pearson cross-correlation method to be efficient for most pairwise calculations (> 85%) but with false positives. One sound type from our repertoire presented a high positive match (range...
Underwater man-made noise is recognized as a major global pollutant in the 21st Century, and its ... more Underwater man-made noise is recognized as a major global pollutant in the 21st Century, and its reduction has been included in national and international regulations. Despite the fact that many studies have pointed out the ecological impact of noise on marine organisms, few studies have investigated - in a field context - the behavioral response to boat noise in fish. In the present study we measure how Sciaena umbra reacts to boat noise. We found that boat noise: i) increased duration of flight reactions and number of individuals performing them, ii) increased the frequency of hiding behaviors, and iii) did not elicit a change in fish activity level and sound emission. Flights and hiding behavior, usually related to predation risk, were not uniform between individuals and showed a quick recovery after noise exposure. On the basis of these results, potential metabolic, physiological and behavioral consequences are discussed and management recommendations are proposed.
Accurate, rapid and cost-effective fish assemblage monitoring is fundamental for marine protected... more Accurate, rapid and cost-effective fish assemblage monitoring is fundamental for marine protected area (MPA) management as a pivotal tool to verify whether and to what extent MPA conservation objectives have been achieved and to redefine these objectives in the framework of an adaptive management. Recently, there has been a sharp increase in the number of video-based methods to study fish fauna, such as baited remote underwater video (BRUV) systems, that, depending on the objectives of the monitoring, can provide complementary or additional data to the more commonly used underwater visual census (UVC). Even though BRUV systems have been widely used in a wide range of geographic contexts and habitats, their use in the Mediterranean basin is still sporadic and the evaluation of the efficiency of BRUV systems and whether they can be used to complement other techniques needs investigation. Thus, the objective of this study was to assess the performance of a BRUV system in a Mediterranea...
Bottlenose dolphin communication has been studied extensively. Nevertheless, the combined effect ... more Bottlenose dolphin communication has been studied extensively. Nevertheless, the combined effect of several variables on whistle structure has yet to be clearly understood. Here, we investigated the influence of underwater noise, boat presence, behaviour, group size and calf presence on the whistles of a small population of common bottlenose dolphins (Tursiops truncatus). Surface behaviour and acoustic data were collected in Sardinia (Italy-Western Mediterranean Sea) between 2015 and 2017. Whistle frequency parameters (minimum, maximum, start, end frequencies and frequency range), duration, number of inflection points and number of harmonics were correlated with the ambient noise levels recorded prior to the whistle display and to behavioural and social factors by means of GAM models. Whistle frequencies varied as a function of the interaction between noise and boat presence, mainly when the noise increased at lower frequencies. Dolphin whistles also varied according to group size, which was further affected by the presence of calves, and behaviours characterised by high levels of arousal such as feeding. The study provides sufficient evidence to support that multiple factors need to be considered when investigating whistle structure as the species is capable of adopting different strategies depending on environmental, social and behavioural context. Finally, this data indicates that communication within a small population of bottlenose dolphins is vulnerable to acoustic pollution, thereby highlighting the need for further investigation into the effects of different noises on whistle structure, as well as the consistency of patterns across different populations.
Whistles are acoustic signals produced particularly during social interactions. Here, we compare ... more Whistles are acoustic signals produced particularly during social interactions. Here, we compare whistles by bottlenose dolphins from three Mediterranean areas (Croatia, Sicily and Sardinia) to investigate the presence of acoustic divergence and to discuss the possible causes of variability. Whistle parameters differ significantly between populations, but PCA highlights that the majority of variability is due to a limited number of frequency parameters. Cluster and DFA show that the Croatian population is acoustically divergent from the western populations of Sicily and Sardinia. This divergence could be consistent with geographical isolation, and a possible genetic differentiation between populations, and/or an adaptation to the acoustic environment. Moreover, in a comparison of whistle parameters of different Mediterranean populations with those of previously published Atlantic populations, it was revealed that the Sicilian population was acoustically closer to Atlantic population...
ABSTRACT Originally developed wideband acoustic bottom recorders were used. Named RASP -programma... more ABSTRACT Originally developed wideband acoustic bottom recorders were used. Named RASP -programmable underwater acoustic recorder, it is hand deployed from a Zodiac and it is featured with an acoustic release. The recorders have a programmable timer that can follow any desired schedule. The system band-width is 10Hz..48kHz and currently offers 32GB of memory per launch. This study returned 251 hours of non continous acoustic re-cordings over 7 months in 14 deployment sites. The recordings cover day/night periods and almost any weather condition. The files were divided into over 3000 units with 5&amp;#39; duration to create a uniform dataset to be statistically analyzed.
In June 1995, an isolated sperm whale, designated SW0695, was acoustically detected, tracked and ... more In June 1995, an isolated sperm whale, designated SW0695, was acoustically detected, tracked and recorded for more than 7 hours in the Ligurian Sea. It was sighted 8 times at the surface and photographs of its fluke were taken and included in the photo-id catalog we have been collecting since 1994. In September 1996 we detected 7 different whales off Cap Corse (France) and we were able to take photographs of the flukes of three of three whales. Among them, the whale designated SW0996A was identified as the same individual we identified and recorded in 1995. For the first time in the Mediterranean Sea the same sperm whale was photo identified and acoustically recorded two times in consecutive years (15 months lapse). In the first sighting (SW0695), Inter Pulse Intervals (IPI) measured 5.17 ms on average, giving a body length of 11.63 or 12.32 meters depending on the equations used. In the second sighting (SW0696A), the IPIs measured 5.39 ms on average corresponding to a body length o...
The effect of anthropogenic noise on the marine environment is a serious concern for scientists (... more The effect of anthropogenic noise on the marine environment is a serious concern for scientists (Richardson et al., 1995; Nascetti et al., 1997; D'Amico, 1998; Frantzis, 1998; AA.VV, 2003) and has gained the attention of public opinion. To reduce the impact of high power underwater sound sources, Acoustic Risk Mitigation Policies have been drawn up and are currently under implementation. Basically, ARMP are aimed at preserving particularly populated areas and critical habitats, and at reducing or stopping emissions if animals are within a defined distance. Among tested approaches, passive acoustics has shown to be an efficient tool to (a) expand knowledge about marine mammal distribution in space and time (i.e. with surveys), (b) characterise biological and artificial sources, (c) evaluate effects of sound exposure on animals' behaviour, and (d) monitor, detect, locate and track vocalising animals within, or approaching, a sound exposure area. Passive acoustics can continuou...
The ability to detect marine mammals in a specific area is a fundamental requirement for the corr... more The ability to detect marine mammals in a specific area is a fundamental requirement for the correct implementation of mitigation procedures aimed at reducing the impact of high power acoustic sources during either civil or military operations. Passive acoustic monitoring is one of the tools used for this task. In order to be detectable, animals must emit acoustic signals whose time-frequency structure and repetition rate are detectable with the used equipment. Cuvier's beaked whale, Ziphius cavirostris, a critical species when sonar operations are concerned, is difficult to detect. Its acoustic features have been discovered recently by using sophisticated digital recording tags (DTAG) developed by WHOI (Johnson et al., 2004;, but traditional sub-surface detection devices have never been proven reliable. CIBRA developed a high quality wideband towed array with the purpose of detecting Cuvier's beaked whales, and tested it in an area hosting a known population. The experiment was a success, with animals recorded after having been sighted. We thus decided to search other recordings made with equivalent equipment in habitats where beaked whales' sightings had occurred or that were at least compatible with their presence. Clicks matching the Cuvier's beaked whale model were found on two more occasions but with some variation from the known model based on DTAG recordings.
Abstract: CIBRA is a research group whose main interest is in the study of underwater sounds rela... more Abstract: CIBRA is a research group whose main interest is in the study of underwater sounds related to marine mammals and in the development of acoustic detection and analysis technologies. The" acoustic" aspect in wide area studies, critical habitat ...
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