Sound Production Rates Research Articles

Effects of mother’s imitation on speech sounds in infants with Down syndrome

BackgroundThe Down syndrome behavioral phenotype includes delays in making speech sounds, production of more non-speech sounds than speech sounds, and contrasting strengths in social development. Within a behavior analytic framework, we conceptualize characteristics of the Down syndrome behavioral phenotype as creating a context for impairments in speech sound development that suggest interventions caregivers can use to improve speech sounds. Aim and methodWe examined one intervention, the effects of mother’s contingent vocal imitation, on rate of speech and non-speech sound production in infants with Down syndrome using an ABAB design. ResultsMothers responded favorably to learning to imitate their infants’ vocalizations and their contingent vocal imitation was associated with increases in infant speech sounds. ConclusionsThe increases in infant speech sound suggest the promise of this approach and future research examining variations in contingent vocal imitation and additional outcomes.

Substrate-borne vibration and sound production by the land hermit crab Coenobita compressus during social interactions

Despite the diversity of sound production in crustacea, sounds produced by the land hermit crabs (Coenobitidae) are not well understood. Here, sound and substrate-borne vibration production by the tropical species Coenobita compressus was characterized in relation to shell architecture and social context. Sound production rates were compared between group and solitary conditions. Chirps were measurable in the air (peak frequency 800-8400 Hz) and within the sediment (40-1120 Hz). On average, chirp pulses were 0.08 s, spaced 0.41-0.92 s apart, and had trains composed of 4-6 pulses. There were significant correlations between the shell architecture and chirp vibroacoustics. Notably, a correlation between the substrate-borne peak frequency and shell wall thickness was found, indicating that the shell remodeling process which crabs undertake (shell wall thinning) impacts the vibroacoustics of the chirps. Chirp production was significantly linked to sociality during increased individual proximity and shell contests; hence, the function is hypothesized to be intraspecific communication relative to personal space and defense. Although there have been anecdotal observations of chirping in the Coenobitidae, this paper provides a full characterization of C. compressus, which produces chirps in two sensory modes, indicating the potential of being a seismic signaler.

Machine learning analysis reveals relationship between pomacentrid calls and environmental cues

Sound production rates of fishes can be used as an indicator for coral reef health, providing an opportunity to utilize long-term acoustic recordings to assess environmental change. As acoustic datasets become more common, computational techniques need to be developed to facilitate analysis of the massive data files produced by long-term monitoring. Machine learning techniques demonstrate an advantage in the identification of fish sounds over manual sampling approaches. Here we evaluated the ability of convolutional neural networks to identify and monitor call patterns for pomacentrids (damselfishes) in a tropical reef region of the western Pacific. A stationary hydrophone was deployed for 39 mo (2014-2018) in the National Park of American Samoa to continuously record the local marine acoustic environment. A neural network was trained—achieving 94% identification accuracy of pomacentrids—to demonstrate the applicability of machine learning in fish acoustics and ecology. The distribution of sound production was found to vary on diel and interannual timescales. Additionally, the distribution of sound production was correlated with wind speed, water temperature, tidal amplitude, and sound pressure level. This research has broad implications for state-of-the-art acoustic analysis and promises to be an efficient, scalable asset for ecological research, environmental monitoring, and conservation planning.

Drivers of male sound production and effective communication distances at fish spawning aggregation sites

AbstractWhile monitoring fish sounds has enhanced our understanding of spatio-temporal patterns of spawning and acoustic communication, data interpretation often fails to account for environmental effects on acoustic recordings, resulting in uncertainty of whether measures of detected fish sounds correspond to rates of sound production, specific behaviours, and abundance. In this study, we applied acoustic propagation modelling and detection theory to estimate rates of sound production of territorial, male Gulf grouper (Mycteroperca jordani) from passive acoustic recordings and evaluate effective communication distances. To assess behavioural drivers, environmentally calibrated, hourly estimates of sound production rates were compared to diver observations of courtship, spawning, and numbers of females encountered within male territories. Rates of sound production increased before sunset and were correlated to observed rates of spawning and females encountered, indicating that sound production is largely driven by female presence and increased opportunities to spawn. The mean effective communication distance was estimated to be <21 m, supporting the importance of short-range communication within the observed behaviours. Our findings corroborate that fish sounds can be used to infer measures of reproductive activity and the relative abundance of both sexes during spawning periods once properly calibrated for environmental effects and detection capabilities.

Characterizing the acoustic behavior of free-ranging Risso’s dolphins (Grampus griseus) in Monterey Bay, California

Risso’s dolphins (Grampus griseus) are a common, highly vocal odontocete species found in Monterey Bay, California, that is relatively understudied acoustically. Although several studies have focused on Risso’s echolocation, there is little research on the other social sound types for this species. Apart from echolocation clicks, the two most common sound types in Risso’s dolphin repertoires are whistles and whistle + burst pulse (whistle BP) vocalizations. In summer 2017, single C57 omnidirectional hydrophone (Cetacean Research Technology) deployments were conducted in Monterey Bay to record Risso’s sound production during periods of slow travel and social interaction at the surface. Group composition information and surface behavioral events were also recorded to provide behavioral context. Average group sizes consisted of approximately 30 animals. We completed a total of 62 h on effort and 75 deployments. Of the 5 total hours of recordings, 43% contained vocalizations. We will describe the acoustic parameters of recorded whistle and whistle BP vocalizations of Monterey Bay Risso’s dolphins, evaluate sound production rate in relationship to surface active behavior, and compare vocalizations with those of geographically isolated populations as well as sympatric odontocete species in the Bay.

Context-dependent variability in blue whale acoustic behaviour.

Acoustic communication is an important aspect of reproductive, foraging and social behaviours for many marine species. Northeast Pacific blue whales (Balaenoptera musculus) produce three different call types—A, B and D calls. All may be produced as singular calls, but A and B calls also occur in phrases to form songs. To evaluate the behavioural context of singular call and phrase production in blue whales, the acoustic and dive profile data from tags deployed on individuals off southern California were assessed using generalized estimating equations. Only 22% of all deployments contained sounds attributed to the tagged animal. A larger proportion of tagged animals were female (47%) than male (13%), with 40% of unknown sex. Fifty per cent of tags deployed on males contained sounds attributed to the tagged whale, while only a few (5%) deployed on females did. Most calls were produced at shallow depths (less than 30 m). Repetitive phrasing (singing) and production of singular calls were most common during shallow, non-lunging dives, with the latter also common during surface behaviour. Higher sound production rates occurred during autumn than summer and they varied with time-of-day: singular call rates were higher at dawn and dusk, while phrase production rates were highest at dusk and night.

Sound production patterns of big-clawed snapping shrimp (Alpheus spp.) are influenced by time-of-day and social context.

Snapping shrimp are perhaps the most pervasive sources of biological sound in the ocean. The snapping sounds of cryptic shrimp colonies in shallow coastal habitats worldwide create a near-continuous crackling with high spatiotemporal variability, yet the underlying acoustic ecology is not well understood. This study investigated sound production rates and acoustic behavior of snapping shrimp species common in the Western Atlantic Ocean and Gulf of Mexico (Alpheus heterochaelis and Alpheus angulosus). Snap rates were measured in a controlled laboratory setting under natural light, temperature, and substrate conditions for shrimp held individually, in pairs, and in a ten-shrimp mesocosm, to test hypotheses that acoustic activity varies with time-of-day and social context. Spontaneous snapping was observed for 81 out of 84 solitary shrimp monitored. Time-of-day influenced snap output for individuals and same-sex pairs-higher rates occurred during dusk and night, compared to daylight hours, but this pattern was inconsistent for opposite-sex pairs and a mixed-sex group. These laboratory results provide insight into behavioral rhythms that may influence snapping patterns in natural populations, and underscore the limited understanding of a major sound source in marine environments.

Using paired visual and passive acoustic surveys to estimate passive acoustic detection parameters for harbor porpoise abundance estimates.

Passive acoustic monitoring is a promising approach for monitoring long-term trends in harbor porpoise (Phocoena phocoena) abundance. Before passive acoustic monitoring can be implemented to estimate harbor porpoise abundance, information about the detectability of harbor porpoise is needed to convert recorded numbers of echolocation clicks to harbor porpoise densities. In the present study, paired data from a grid of nine passive acoustic click detectors (C-PODs, Chelonia Ltd., United Kingdom) and three days of simultaneous aerial line-transect visual surveys were collected over a 370 km2 study area. The focus of the study was estimating the effective detection area of the passive acoustic sensors, which was defined as the product of the sound production rate of individual animals and the area within which those sounds are detected by the passive acoustic sensors. Visually estimated porpoise densities were used as informative priors in a Bayesian model to solve for the effective detection area for individual harbor porpoises. This model-based approach resulted in a posterior distribution of the effective detection area of individual harbor porpoises consistent with previously published values. This technique is a viable alternative for estimating the effective detection area of passive acoustic sensors when other experimental approaches are not feasible.

Acoustic behavior associated with cooperative task success in bottlenose dolphins (Tursiops truncatus).

Although many species have proven capable of cooperating to achieve common goals, the role of communication in cooperation has received relatively little attention. Analysis of communication between partners is vital in determining whether actions are truly cooperative rather than serendipitous or learned via trial and error (Chalmeau and Gallo in Behav Process 35:101-111, 1996a. doi: 10.1016/0376-6357(95)00049-6 , Primates 37:39-47, 1996b. doi: 10.1007/BF02382918 ). Wild cetaceans often produce sounds during cooperative foraging, playing, and mating, but the role of these sounds in cooperative events is largely unknown. Here, we investigated acoustic communication between two male bottlenose dolphins while they cooperatively opened a container (Kuczaj et al. in Anim Cogn 18:543-550, 2015b. doi: 10.1007/s10071-014-0822-4 ). Analyses of whistles, burst pulses, and bi-phonations that occurred during four contexts (i.e., no container, no animals interacting with container, one animal interacting with container, and two animals interacting with container) revealed that overall sound production rate significantly increased during container interactions. Sound production rates were also significantly higher during cooperative successes than solo successes, suggesting that the coordination of efforts rather than the apparatus itself was responsible for the phonation increase. The most common sound type during cooperative successes was burst pulse signals, similar to past recordings of cooperative events in bottlenose dolphins (Bastian in Animal sonar systems. Laboratoire de Physiologie Acoustique, Jouy-en Josas, pp 803-873, 1967; Connor and Smolker 1996).

Variation in the emission rate of sounds in a captive group of false killer whales Pseudorca crassidens during feedings: possible food anticipatory vocal activity?

This study examines whether a group of captive false killer whales (Pseudorca crassidens ) showed variations in the vocal rate around feeding times. The high level of motivation to express appetitive behaviors in captive animals may lead them to respond with changes of the behavioral activities during the time prior to food deliveries which are referred to as food anticipatory activity. False killer whales at Qingdao Polar Ocean World (Qingdao, China) showed significant variations of the rates of both the total sounds and sound classes (whistles, clicks, and burst pulses) around feedings. Precisely, from the Transition interval that recorded the lowest vocalization rate (3.40 s/m/d), the whales increased their acoustic emissions upon trainers’ arrival (13.08 s/m/d). The high rate was maintained or intensified throughout the food delivery (25.12 s/m/d), and then reduced immediately after the animals were fed (9.91 s/m/d). These changes in the false killer whales sound production rates around feeding times supports the hypothesis of the presence of a food anticipatory vocal activity. Although sound rates may not give detailed information regarding referential aspects of the animal communication it might still shed light about the arousal levels of the individuals during different social or environmental conditions. Further experiments should be performed to assess if variations of the time of feeding routines may affect the vocal activity of cetaceans in captivity as well as their welfare.

Measuring whale and dolphin call rates as a function of behavioral, social, and environmental context

Cetacean sound-production rates are highly variable and patchy in time, depending upon individual behavior, social context, and environmental context. Better quantification of the drivers of this variability should allow more realistic estimates of expected call rates, improving our ability to convert between call counts and animal density, and also facilitating detection of sound-production changes due to acoustic disturbance. Here, we analyze digital acoustic tag (DTAG) records and visual observations collected during behavioral response studies (BRSs), which aim to assess normal cetacean behavior and measure changes in response to acoustic disturbance; data sources include SOCAL BRS, the 3S project, and Bahamas BRS, with statistical contributions from the MOCHA project (http://www.creem.st-and.ac.uk/mocha/links). We illustrate use of generalized linear models (and their extensions) as a flexible framework for sound-production-rate analysis. In the context of acoustic disturbance, we also detail use of two-dimensional spatially adaptive surfaces to jointly model effects of sound-source proximity and sound intensity. Specifically, we quantify variability in pilot whale group sound production rates in relation to behavior and environment, and individual fin whale call rates in relation to social and environmental context and dive behavior; with and without acoustic disturbance.

Preliminary calculation of individual echolocation signal emission rate of Franciscana dolphins (Pontoporia blainvillei)

Calculation of echolocation signals emission rate is necessary to estimate how many individuals are vocalizing, especially if passive acoustic density estimation methods are to be implemented. We calculated the individual emission rate of echolocation signals of franciscana dolphin. Fieldwork was between 22 and 31 January of 2014 at Babitonga Bay, Brazil. Acoustic data and group size were registered when animals were within visual range at maximum distance of 50 meters. We used a Cetacean Research™ hydrophone. The sound was digitized by Analogic/Digital IOtech, stored as wav-files and analyzed with Raven software. A band limited energy detector was set to automatically extract echolocation signals. The emission rate was calculated dividing the clicks registered for each file by the file duration and by the number of individuals in the group. We analyzed 240 min of sound of 36 groups. A total of 29,164 clicks were detected. The median individual click rate was 0.290 clicks/s (10th = 0.036 and 90th = 1.166 percentiles). The result is a general approximation of the individual echolocation signal emission rate. Sound production rates are potentially dependent on a number of factors, like season, group size, sex, or even density itself. [This study was supported by IWC/Australia, Petrobras, Fundo de Apoio à Pesquisa/UNIVILLE.]

Estimating density from passive acoustics: Are we there yet?

In the last few years, there have been a considerable number of papers describing methods or case studies involving passive acoustic density estimation. While this might be interpreted as evidence that density estimates might now be easily and routinely implemented, the truth is that so far these methods and applications have been essentially proof-of-concept in nature, based in areas and/or species particularly suited for the methods and also often involved assumptions hard to evaluate. We briefly review some of the existing work in this area concentrating on a few aspects we believe are key for the implementation of density estimation from passive acoustics in a broader context. These are (1) the development of fundamental research addressing the problem of sound production rate, fundamental as it allows to convert estimates of density of sounds into density of animals and (2) the development of hardware capable of providing cheap deployable units capable of ranging, allowing straightforward implementations of distance sampling based approaches. The perfect density estimate is out there waiting to happen, but we have not found it yet.

Acoustically invisible feeding blue whales in Northern Icelandic waters.

Fixed passive acoustic monitoring can be used for long-term recording of vocalizing cetaceans. Both presence monitoring and animal density estimation requires the call rates and sound source levels of vocalizations produced by single animals. In this study, blue whale calls were recorded using acoustic bio-logging systems in Skjálfandi Bay off Húsavík, Northeast Iceland, in June 2012. An accelerometer was attached to individual whales to monitor diving behavior. During 21 h recording two individuals, 8 h 45 min and 13 h 2 min, respectively, 105 and 104 lunge feeding events and four calls were recorded. All recorded calls were down-sweep calls ranging from 105 to 48 Hz. The sound duration was 1-2 s. The source level was estimated to be between 158 and 169 dB re 1μPa rms, assuming spherical sound propagation from the possible sound source location to the tag. The observed sound production rates and source levels of individual blue whales during feeding were extremely small compared with those observed previously in breeding grounds. The feeding whales were nearly acoustically invisible. The function of calls during feeding remains unknown.

Variation in the acoustic behavior of right whale mother-calf pairs

North Atlantic right whale mother-calf pairs are a critical segment of the population for recovery of this endangered species and therefore their protection is paramount. Passive acoustics, including the development of real-time buoys, has increasingly played a role in the detection of right whale presence in high vessel traffic areas. The vocal behavior of North Atlantic right whale mothers and their young calves has not been well described and may not be well represented by calls produced by other individuals in the population that are commonly utilized for passive acoustic monitoring. Therefore, it is critical to determine the call types and rates of sound production by mother-calf pairs to assess the efficacy of passive acoustic monitoring for their detection. We conducted behavioral focal follows coupled with acoustic recording of right whale mother calf pairs off the coast of Florida and Georgia in January–March, Cape Cod Bay in April, and the Bay of Fundy in August–September from 2011 to 2014. Results show modifications in both call structure and call rate with increasing calf maturity and independence. These data are necessary to better utilize passive acoustic monitoring for management purposes in this species.

Acoustic characterization and vocal behavior of North Atlantic right whale surface active groups

Focal acoustic surveys were conducted to assess the vocal behavior of North Atlantic right whales in the shallow waters of the southeast critical habitat. Underwater vocalizations were archived using autonomous buoys in close proximity to surface active groups (SAGs) providing sound production data vital for regional passive acoustic monitoring and conservation. Classification trees were used to examine the distinguishing characteristics of calls and quantify their variability within the surface active groups vocal repertoire. Calling rates were higher than those reported in the Bay of Fundy, which may be a factor of habitat demographics. Sound production rate and call type usage were correlated with group cohesion, revealing a consistent call distribution pattern across SAGs of varying sizes and composition. The within-bout clustering probability of low and high frequency calls suggest that temporal affinities between vocalization classes may be indicators of shared social functions. The results demonstrate that concurrent temporal and spectral analysis is powerful for investigating and presenting the interrelationships of calls with social behavior and group composition.

The Role of Agonistic Sounds in Male Nest Defence in the Painted Goby Pomatoschistus pictus

AbstractAnimals often vocalize during territorial challenges as acoustic signals may indicate motivation and fighting ability and contribute to reduce aggressive escalation. Here, we tested the function of agonistic sounds in territorial defence in the painted goby. Pomatoschistus pictus, a small vocal marine fish that defends nests during the breeding season. We first measured the number of times a male approached, avoided, explored, entered and exited two unattended nests associated with either conspecific agonistic sounds or a control: silence or white noise. Acoustic stimuli were played back when the male approached a nest. In a second experimental set, we added visual stimuli, consisting of a conspecific male in a small confinement aquarium near each nest. Even though we found no effect of the visual stimuli, the sound playbacks induced similar effects in both experimental conditions. In the sound vs. silence treatment, we found that when males approached a nest, the playback of conspecific sounds usually triggered avoidance. However, this behaviour did not last as in longer periods males visited nests associated with agonistic sounds more often than silent ones. When the control was white noise, we found no significant effect of the playback treatment in male behaviour. Although we cannot exclude the possibility that other sounds may dissuade nest occupation, our results suggest that agonistic sounds act as territorial intrusion deterrents but are insufficient to prevent nest intrusion on their own. Further studies are needed to test the significance of sound production rate, spectral content and temporal patterns to deter territorial intrusion in fish.

Sounds associated with the reproductive behavior of the black grouper (Mycteroperca bonaci)

Passive acoustic and synchronous video recordings were made at two spawning aggregation sites to study the sounds associated with reproductive behaviors of Mycteroperca bonaci. A characteristic sound was produced during courtship displays involving behaviors commonly observed for groupers of this genus at aggregations. The sound has a short pulsing section followed by a longer tonal portion with a mean peak frequency below 100 Hz. Courtship-associated sounds were quantified over one spawning season at Mona Island, Puerto Rico. Most of the daily sound production occurred during a period of 2 h prior to sunset. The highest rates of sound production lasted for a period of 10 days with lunar periodicity over three consecutive months coincident with the reported season of reproduction. Passive acoustics provide a tool to measure the variability of the reproductive activity of M. bonaci over time and may provide a method to evaluate current strategies designed to protect multi-species spawning aggregations that are critical for the recovery of threatened groupers.

Variation in the production rate of biosonar signals in freshwater porpoises

The biosonar (click train) production rate of ten Yangtze finless porpoises and their behavior were examined using animal-borne data loggers. The sound production rate varied from 0 to 290 click trains per 10-min time interval. Large individual differences were observed, regardless of body size. Taken together, however, sound production did not differ significantly between daytime and nighttime. Over the 172.5 h of analyzed recordings, an average of 99.0% of the click trains were produced within intervals of less than 60 s, indicating that during a 1-min interval, the number of click trains produced by each porpoise was typically greater than one. Most of the porpoises exhibited differences in average swimming speed and depth between day and night. Swimming speed reductions and usage of short-range sonar, which relates to prey-capture attempts, were observed more often during nighttime. However, biosonar appears to be affected not only by porpoise foraging, but also by their sensory environment, i.e., the turbid Yangtze River system. These features will be useful for passive acoustic detection of the porpoises. Calculations of porpoise density or abundance should be conducted carefully because large individual differences in the sound production rate will lead to large estimation error.

Individual variability of echolocation and diving behavior of Yangtze finless porpoises

Passive acoustic monitoring has been widely applied to observe the presence, movement and behavior of the target species. For quantitative analysis, the acoustic cue production rate of the target animals must be observed in advance. We examined the detailed pattern of biosonar and swimming behaviors of 10 Yangtze finless porpoises (1 female and 9 males) obtained by electronic tags attached to the animals. The click trains produced by the tagged animal were identified out of other animals' vocalizations using bearing angles calculated by the time-of- arrival differences of the sounds between the two hydrophones in the acoustic tag. The number of click trains produced in 10 min did not relate to the body size or sex and varied from 0 to 290. Although deeper the animals dive, faster they swam, the speed or maximum depth of the animals had no correlation with the number of click trains produced or body size. All parameters we examined had no diurnal rhythm but had independent aperiodic variation. The sound production rate without day or night bias is suitable for the quantitative passive acoustic monitoring of this species.