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PRODUCTION OF UNDERWATER SOUND BY THE WHITE WHALE OR BELUGA,DELPHINAPTERUS LEUCAS(PALLUS)
... However, only a few studies are devoted to the features of communication between beluga whales. Meanwhile, they helped to reveal a general correlation between the vocal signalization and animal behavior [5,11,14,22] and to examine the particular types of acoustic activity at searching-hunting behavior [5] and in stress situations [8]. Nevertheless, the results obtained, including the data of the experiments on the playback of conspecific signals to belugas [19], did not allow one to estimate unambiguously the significance of vocalizations. ...
... The "squeaks" of beluga whales are traditionally related to the emotional excitement of the animals in certain kinds of activity [5,14,19]. The results obtained by us cast some doubt on the existence of a tight relation between the "squeaks" and emotional excitement. ...
... Another pattern is observed from the assessment of "vocal" signals such as "bleating" and "vowels." The studies of beluga whales in oceanaria helped to recog-nize the important role of these signals for direct contacts between the animals [14,19]. In the early studies of the White Sea and Far East beluga whales, the high percentage of them in "dialogs" for "long" and, especially, "close-range" communication was also noted [5]. ...
In July and August 2001, we studied the underwater acoustic communication of beluga whales off Cape Beluzhii (Solovetskii Island, White Sea). The signaling was studied in four behavioral situations: quiet swimming, social interactions, sexual behavior, and disturbance caused by man. It was established that the over-all vocalization rate and rate of six main types of signals (signal/min; signal whale-1 min-1) strongly depend on the underlying behavior. The percentage of the main types of signals is less related to the behavior of the belugas. However, the proportions between the four main types of signals significantly change with regard to different behavioral activities of the animals. Social interactions are characterized by an increase in the relative use of "chirping" and "bleating" and a decrease in the use of "vowels." An increase in the use of "chirping" accompanied by a simultaneous decrease in the use of "whistles" was observed during sexual behavior. The results of discriminant analysis based on the characteristics of the whale acoustic signaling allowed us to identify correctly 67.3% of the behavioral situations, which suggests the presence of a general correlation between the behavior and the acoustic activity of belugas.
... Intervals between bursts were generally of 0.05 to 0.5 seconds. Fundamental frequencies were in the range of 200 to 300 Hz -similar to human speech and several octaves lower than the whale's usual sounds [4]. Spectral characteristics with multiple harmonics were unlike usual whale sounds but not unlike those Although dolphins (Tursiops truncatus) have been trained to match numbers and durations of human vocal bursts [1] and reported to spontaneously match computer-generated whistles [2], spontaneous human voice mimicry has not previously been demonstrated. ...
... The first to study white whale (Delphinapterus leucas) sounds in the wild, Schevill and Lawrence [3] wrote that "occasionally the calls would suggest a crowd of children shouting in the distance". Fish and Mowbary [4] described sound types and reviewed past descriptions of sounds from this vociferous species. At Vancouver Aquarium, Canada, keepers suggested that a white whale about 15 years of age, uttered his name "Lagosi". ...
... However, NOC remained quite vocal. He produced typical echolocation pulses with peak frequencies between 60 and 120 kHz, whistles with fundamental frequencies of 2 to 10 kHz and various pulse burst sounds previously described as "squawks, rasps, yelps or barks" [4]. ...
Although dolphins (Tursiops truncatus) have been trained to match numbers and durations of human vocal bursts [1] and reported to spontaneously match computer-generated whistles [2], spontaneous human voice mimicry has not previously been demonstrated. The first to study white whale (Delphinapterus leucas) sounds in the wild, Schevill and Lawrence [3] wrote that "occasionally the calls would suggest a crowd of children shouting in the distance". Fish and Mowbary [4] described sound types and reviewed past descriptions of sounds from this vociferous species. At Vancouver Aquarium, Canada, keepers suggested that a white whale about 15 years of age, uttered his name "Lagosi". Other utterances were not perceptible, being described as "garbled human voice, or Russian, or similar to Chinese" by R.L. Eaton in a self-published account in 1979. However, hitherto no acoustic recordings have shown how such sounds emulate speech and deviate from the usual calls of the species. We report here sound recordings and analysis which demonstrate spontaneous mimicry of the human voice, presumably a result of vocal learning [5], by a white whale.
... The beluga whale Delphinapterus leucas produces a variety of sounds including whistles as well as pulsed, noisy and biphonic vocalizations (Fish and Mowbray, 1962;Sjare and Smith, 1986a;Bel'kovitch and Sh'ekotov, 1993;Karlsen et al., 2002;Chmelnitsky and Ferguson, 2012;Garland et al., 2015). In the vocal repertoires of many populations, whistles are the most diverse and numerous class of calls (Sjare and Smith, 1986a;Karlsen et al., 2002;Belikov and Bel'kovich, 2007;Chmelnitsky and Ferguson, 2012;Garland et al., 2015). ...
... Biphonations, otherwise called as "combined" (Karlsen et al., 2002;Chmelnitsky and Ferguson, 2012), "mixed" (Vergara et al., 2010), or "complex" (Vergara and Mikus, 2019) vocalizations, are also well known for belugas. Their ability to produce combinations of whistles and pulsed sounds was noted in the first study of their vocal behavior in captivity (Fish and Mowbray, 1962). Recent research has revealed a key role of some stereotyped biphonic sounds in belugas' communication, as they serve as contact recognition calls (Vergara and Barrett-Lennard, 2008;Vergara et al., 2010;Vergara and Mikus, 2019). ...
The beluga whale (Delphinapterus leucas) produces a variety of sounds, including whistles as well as pulsed, noisy, and biphonic vocalizations. This study presents the fine-scale, microgeographic characteristics of beluga whistles from data collected in four locations across Onega Bay and Dvina Bay in the White Sea, Russia. Ten parameters were measured from 1232 whistles. The whistles had a fundamental frequency from 0.4 to 25.0 kHz and duration from 0.04 to 3.93 s. Although two distinct types could be recognized in the White Sea beluga's whistle repertoire, other whistles formed a graded continuum. Among them, “flat” whistle contours with no inflection points appear to be the most common (39.7%), to be followed by frequency-modulated whistles: ascending (27.1%) and descending (15.6%). Non-linear phenomena detected in the whistles included frequency jumps (23.1%), biphonations (13.2%), sidebands (5.2%), and subharmonics (0.5%). The whistles varied in frequency parameters and duration across the locations, while those recorded in the same location in different years showed minimal difference. Beluga whistles appear to be an extremely diverse class of vocalizations. This, together with the lack of clear correlations between the behavior of whales and whistle production suggests whistles may perform multiple functions within the beluga whale communication system.
... Since then, there have been a number of attempts to classify the vocal repertoire of belugas, summarized in Table 1. It is immediately apparent, when one examines this body of data, that the classification of the vocal repertoire of belugas into principal call types has suffered, as have other cetacean studies, from classification inconsistencies between researchers, rendering anywhere from nine (Fish and Mowbray 1962) to 52 call types (Belikov and Bel'kovich 2006; Presented 12 call types and representative spectrograms of six general signal classes: "squeaks", "whistles", "bleatings", "chirpings", "vowels", "creaks," in addition to mixed pulsed/tonal calls. ...
... Belugas are one of the most vocal odontocete species, producing highly varied communication calls (Schevill and Lawrence 1949;Fish and Mowbray 1962;Sjare and Smith 1986a, b;Karlsen et al. 2002), as well as possessing an unparalleled echolocation system (Au 1985;Turl et al. 1987;Turl et al. 1991; see Chapter 1 for further detail). There is much to be To examine the issues outlined above, I studied the vocal development of a male beluga calf, Tuvaq, at the Vancouver Aquarium, longitudinally from the moment of his birth, throughout his first year of life and opportunistically through his second and third, providing the first account of the sequencing and timing of vocal acquisition in a beluga whale. ...
Belugas (Delphinapterus leucas) are highly vocal cetaceans, but the function of their calls, repertoire ontogeny, and role of learning in vocal behavior are poorly understood. This dissertation examines these issues, focusing on a captive beluga group at the Vancouver Aquarium. First, I investigated vocal development in a beluga calf, longitudinally throughout his first year of life, and later opportunistically. The first sounds after birth were low energy, broadband pulse-trains, which increased in pulse repetition rate with age. He incorporated rudimentary whistles at two weeks. His mixed calls, which became consistent at four months, became progressively stereotyped, increasingly like his mother’s “Type-A” call, a presumed contact call. Six months after he was first exposed to his father’s calls, he developed a call type similar to one of his father’s. I discuss these findings in light of theories of sound production mechanisms, developmental stages of vocal acquisition, and vocal learning.
Secondly, I examined context-specific use of call types recorded from the beluga group, with particular focus on the Type-A call. This signal constituted 24-97% of the vocalizations during isolation, births, deaths, presence of external stressors, and re-union of animals after separation. In contrast, it represented 4.4% of the vocalizations during regular sessions. I identified five Type-A variants subjectively and quantitatively. I used these findings to generate hypotheses about the usage of these signals by wild belugas, verified the existence of A-calls in the repertoire of St. Lawrence herds, and documented their usage by two wild individuals from different populations in contexts that supported their contact function.
Finally, I investigated contextual vocal learning in trained tasks in adult belugas, focusing on the ability of a female beluga to respond to playbacks of two categories of beluga calls with matching vocalizations; pulse-trains are a natural category, and screams an artificial class shaped by training. The subject successfully matched only pulse-trains, the class that is part of this species’ natural repertoire. Her poor performance on matching screams might be partly explained by a difficulty to perceive categorically a signal that lacks a function in the natural repertoire of belugas.
... The degree of exposure to human activities and interactions have also been found influential on the rate of the acoustic emissions of dolphins (Smolker et al., 1993;Scarpaci et al., 2000;Mann and Kemps, 2003;Morisaka et al., 2005;Hawkins and Gartside, 2009a, b). For example, an increase of all types of underwater sounds have been recorded in different captive cetaceans (bottlenose dolphins, Tursiops truncatus: Tyack, 1986;Janik et al., 1994;Sekiguchi and Koshima, 2003;Akiyama and Ohta, 2007; Beluga whales, Delphinatuera leuca: Fish and Mowbray, 1962; Pacific white-sided dolphins, Lagenorhynchus obliquidens: Brickman, 2003) during activities that were special moments for the dolphins such as training, feeding sessions, or public presentations which might have increased the level of excitement of the animals (Tyack, 1986;Janik et al., 1994). Immediately after all the performances were terminated the rate of the sounds emitted by the dolphins per hours declined (Brickman, 2003;Sekiguchi and Koshima, 2003;Tanchez, 2003). ...
... During our study, a further rise of false killer whales' acoustic rates was recorded during feeding sessions, which showed the highest rate of total sounds and sound classes among all intervals considered. These findings are in accordance with previous observations carried out on captive beluga whales (Delphinaptera leuca, Fish and Mowbray, 1962;Tanchez, 2003), bottlenose dolphins (Tursiops truncatus, Sekiguchi and Kohshima, 2003), and Pacific white-sided dolphins (Lagenorhynchus obliquidens, Brickman, 2003), in which the highest vocal rate was recorded during feeding sessions. ...
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.
... Sound production by captive dolphins and whales often occurs in conjunction with human activity such as feeding, training sessions, or public presentations. Beluga whales at the New York Aquarium became more acoustically active during feedings (Fish & Mowbray, 1962). Captive bottlenose dolphins at three aquaria in Japan were most acoustically active during the day when human caretakers were present (Sekiguchi & Kohshima, 2003). ...
... Similar to other studies on diel variation in underwater sound production by odontocetes in captive environments (Fish & Mowbray, 1962;Brickman, 2003;Sekiguchi & Kohshima, 2003;Tanchez, 2003), bottlenose dolphins at the Brookfield Zoo were most acoustically active during the day when the facility was open to the public and the staff was present. Increased whistle production coincided with increased interactions with humans such as during feeding, presentations, and training. ...
This study investigated diel changes in ambient noise levels and the number of whistles produced by bottlenose dolphins (Tursiops truncatus) at the Brookfield Zoo in Brookfield, Illinois. Automated, continuous 24-h underwater recordings were made from 1 January to 31 March 2008. The number of whistles, types of whistles, and background noise level were examined for each hour. Nine distinct frequency contours were identified, named, and analyzed for minimum frequency, maximum frequency, peak frequency, and duration. Since all pumps and filters at the Seven Seas Exhibit of Brookfield Zoo were housed in a separate building isolated from the dolphins' pools, background noise was relatively low and consistent throughout the day (95 to 98 dB re: 1 μPa). However, when the zoo staff used a scrubber to clean the pool walls, the background noise was higher and fluctuated (up to 112 dB re: 1 μPa). The dolphins whistled significantly less during these scrubbing periods. The dolphins exhibited a distinct diel pattern in whistle production. Increased whistle production coincided with increased interactions with humans during feeding/training sessions; the number of whistles peaked in the late afternoon (~1600 h) and then quickly tapered off throughout the night. The investigation began with eight dolphins; however, the death of one young male and the transport of two adult males to another facility left five dolphins: two adult females and two juvenile females along with an unrelated young male. These changes provided an opportunity to explore how social change affected whistle production. After the two adult males were transported out of the facility, two of the distinct whistle types disappeared, suggesting that each of the two dolphins had a unique whistle type. The results of this investigation highlight the usefulness of passive recording for monitoring ambient noise, as well as for documenting the activity pattern and social interactions of captive bottlenose dolphins.
... Fundamental frequency, harmonic structures, and auxiliary sounds have been used in previous studies to classify vocalizations in several species of whale and pinniped. Fundamental frequency range has been used to classify vocalizations of belugas (Delphinapterus leucas) (Fish and Mowbray 1962;Sjare and Smith 1986b), narwhals (Monodon monoceros) (Ford and Fisher 1978), pilot whales (Globicephala melaena) (Weilgart and Whitehead 1990), humpback whales (Megaptera novaeangliae) (Payne and McVay 1971), harp seals Can. J. Zool. ...
... (Phoca groenlandica) (Mghl et al. 1975), leopard seals (Hydrurga leptonyx) (Stirling and Siniff 1979), Weddell seals (Leptonychotes weddelli) (Thomas and Kuechle 1982), and bearded seals (Erignathus barbatus) (Cleator et al. 1989). Auxiliary sounds have been used to classify vocalizations of Ross seals (Ornmatophoca rossi) (Watkins and Ray 1977), harp seals (Mghl et al. 1975), Weddell seals (Thomas and Kuechle 1982), and belugas (Fish and Mowbray 1962). The presence or absence of harmonics has been used by Thomas and Stirling (1983) and by Mghl et al. (1975) for classifying Weddell and harp seal vocalizations. ...
Grey seals (Halichoerus grypus) breed both on land and on the ice. In January 1991, 36 h of underwater recordings were made from Amet Island, located in ice-covered waters in the southern Gulf of St. Lawrence. All vocalizations were examined for spectral and temporal structure and then classified into 1 of 7 call types. The majority of calls consisted of guttural "rups" and "rupes" (frequency = 100–3000 Hz), and low-frequency growls (100–500 Hz). Other less common vocalizations were low-frequency clicks (3000 Hz), as well as loud knocks, similar to knocking vocalizations recorded in walrus, and which had not been described previously for grey seals. The total number of vocalizations and the number of specific call types showed seasonal variations. The rate of vocalizations increased with the intensity of social activity and with the number of agonistic behaviors during the progression of the breeding season. Comparisons between night and day showed some changes in the vocal repertoire. Low-frequency clicks were recorded more often during darkness (17.1% of calls) than in daylight (1.9%), and when ice cover was more extensive.
... In this study, the 9-day monitoring results of the vocalization events of the YFPs showed that there were diurnal variations in their vocal activity, with five peak time periods (12:00-13:00, 16:00-17:00, 19:00-20:00, 21:00-22:00, and 0:00-1:00) corresponding to the five feeding periods. The YFPs emitted echolocation signals significantly more frequently during feeding than in the free-swimming condition, a phenomenon that has also been observed in studies of toothed whales such as beluga whales (Delphinapterus leucas) [33], and bottlenose dolphins (Tursiops truncatus) [34]. This may be related to the fact that YFPs emit predatory signals during feeding, especially buzz signals when catching prey [20], leading to a significant increase in pulse signals; it is also possible that the presence of live bait during feeding caused the YFPs to increase the frequency of emitting echolocation signals. ...
The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis, YFP) possesses the ability to detect distance through echolocation signals, and its sonar signal signature is adjusted to detect different targets. In order to understand the vocal characteristics of YFPs in different behavioral states and their differential performance, we recorded the vocal activities of YFPs in captivity during free-swimming, feeding, and nighttime resting and quantified their signal characteristic parameters for statistical analysis and comparison. The results showed that the number of vocalizations of the YFPs in the daytime free-swimming state was lower than that in the feeding and nighttime resting states, and the echolocation signals emitted in these three states showed significant differences in the −10 dB duration, −3 dB bandwidth, −10 dB bandwidth, and root-mean-square (RMS) bandwidth. Analysis of the resolution of the echolocation signals of the YFPs using the ambiguity function indicated that their distance resolution could reach the millimeter level. These results indicate that the echolocation signal characteristics of YFPs present diurnal differences and that they can be adjusted with changes in their detection targets. The results of this study can provide certain scientific references and foundations for the studies of tooth whale behavioral acoustics, and provide relevant scientific guidance for the conservation and management of YFPs.
... One of the fundamental knowledge gaps that remain for the CIB population is information surrounding their sociality and communication. Beluga whales are a highly gregarious and vocal species, producing a wide array of vocalizations, including whistles, pulsed calls, combined calls, and echolocation clicks (Au et al., 1985;Fish and Mowbray, 1962). Whistles are narrowband, tonal signals that can be flat (i.e., little or no frequency modulation) or frequency modulated and can contain harmonics that are lower in amplitude. ...
Many species rely on acoustic communication to coordinate activities and communicate to conspecifics. Cataloging vocal behavior is a first step towards understanding how individuals communicate information and how communication may be degraded by anthropogenic noise. The Cook Inlet beluga population is endangered with an estimated 331 individuals. Anthropogenic noise is considered a threat for this population and can negatively impact communication. To characterize this population's vocal behavior, vocalizations were measured and classified into three categories: whistles (n = 1264, 77%), pulsed calls (n = 354, 22%), and combined calls (n = 15, 1%), resulting in 41 call types. Two quantitative analyses were conducted to compare with the manual classification. A classification and regression tree and Random Forest had a 95% and 85% agreement with the manual classification, respectively. The most common call types per category were then used to investigate masking by commercial ship noise. Results indicate that these call types were partially masked by distant ship noise and completely masked by close ship noise in the frequency range of 0–12 kHz. Understanding vocal behavior and the effects of masking in Cook Inlet belugas provides important information supporting the management of this endangered population.
... Despite many descriptions of the beluga whale's extensive vocal repertoire (Fish & Mowbray 1962;Sjare & Smith 1986a;Faucher 1988;Angiel 1997;Karlsen et al. 2002;Belikov & Bel'kovich 2006Panova et al. 2012), and some progress correlating call rates and broad call classes with general behavioural states (e.g., Sjare & Smith 1986b;Belikov & Bel'kovich 2003), little is known about the particular function of most beluga communication signals. Those that function to establish or maintain contact between individuals are a notable exception, as much is currently known about these signals. ...
Noise and anthropogenic disturbances from vessel traffic are an important threat to the recovery of the endangered St. Lawrence Estuary (SLE) beluga population. The consequences of acoustic masking could be particularly adverse in the case of critical vocalizations that maintain contact between mothers and their dependent but mobile calves. This study models the communication range of adults, sub-adults and newborn beluga contact calls in the presence and absence of vessels in an important summering area for this population. Ambient noise measurements, a composite beluga audiogram and apparent source levels of adult/sub-adult and newborn calls, informed the model. Apparent source levels were estimated from received levels of contact calls produced by four individuals carrying digital acoustic tags in the SLE, Canada, and from received levels of calls recorded from two adults and a newborn calf at an aquarium, at known distances from a calibrated hydrophone. The median communication ranges were over 18 times larger for SLE adult and sub-adult calls than for newborn calls, with a 57 and 53% reduction in range in the presence of vessel noise, respectively. For newborn calls, this results in a median range of 170 m in vessel noise. These first estimates of the communication range of beluga vocalizations with a known function suggest that masking of the quiet calls of newborns by anthropogenic noise could impair mother–calf contact.
... Yangtze finless porpoises produced more clicks during training/feeding sessions than outside of such sessions. This pattern has already been reported in other captive odontocetes with an increase in all types of underwater sounds during training/feeding/public presentations (bottlenose dolphins [42,[72][73][74][75]; belugas, Delphinapterus leucas [76]; Pacific white-sided dolphins, Lagenorhynchus obliquidens [77]). Such routine events might have caused an increased level of excitement or anticipation [72,73]. ...
Yangtze finless porpoises use high-frequency clicks to navigate, forage, and communicate. The way in which click production may vary depending on social or environmental context has never been investigated. A group of five captive Yangtze finless porpoises was monitored for one year, and 107 h of audio recordings was collected under different conditions. Using a MATLAB-generated interface, we extracted click density (i.e., number of clicks per minute) from these recordings and analyzed its variation depending on the context. As expected, click density increased as the number of animals present increased. The click density did not exhibit diurnal variations but did have seasonal variations, with click density being highest in summer and fall. Yangtze finless porpoises produced more clicks when socially separated than when not (136% more), during training/feeding sessions than outside of such sessions (312% more), when enrichment was provided (265% more on average), and when noisy events occurred rather than when no unusual event occurred (22% more). The click density decreased when many visitors were present in the facility (up to 35% less). These results show that Yangtze finless porpoises modulate their click production depending on the context and suggest that their echolocation activity and their emotional state may be linked to these changes. Such context-dependent variations also indicate the potential usefulness of monitoring acoustical activity as part of a welfare assessment tool in this species. Additionally, the click density variation found in captivity could be useful for understanding click rate variations of wild populations that are hardly visible.
... Beluga whales (Delphinapterus leucas) are among the most vocal cetaceans, producing a rich diversity of sounds (Fish and Mowbray 1962, Sjare and Smith 1986b, Karlsen et al. 2002. Like other odontocetes, their sounds can be broadly categorized as narrow-band tonal calls referred to as whistles, used socially, and broadband pulsed signals that include echolocation clicks, and social calls like burst-pulsed sounds, trains of pulses with high pulse repetition rates that sound to the human ear like creaks, squawks, screams, or even whistles. ...
A bstract
Broadband, pulsed contact calls have been described for captive and temporarily restrained belugas, but little information exists on their usage in the wild. We examined vocal production during 14 natural beluga entrapments in a shallow channel in Cunningham Inlet, as isolation events offer ideal contexts to study contact calls. Drone footage, overhead photos, and shore‐based photos confirmed the number of individuals and age composition in each entrapment. Contact calls comprised the majority (61%) of vocalizations produced by entrapped whales compared to the free‐ranging herd (10%). We divided contact calls into complex (80%), those with a stereotyped, spectrographically prominent component overlapping the pulse train that characterizes all beluga contact calls, and simple (20%), those with no overlapping component. For each entrapment, we generated a catalogue of complex contact call types, totaling 87 types. Our classification was corroborated both quantitatively and by 55 naïve human judges. Occasional instances of overlapping contact calls of the same type indicated dyadic production. The number of contact call types per entrapment was strongly related to (never exceeding) the number of individuals, excluding neonates. Although this suggests a system of vocal signatures in belugas, consistent with their fission‐fusion society and earlier findings, whether signature identity is encoded individually or shared with related animals remains unknown.
... Decreasing whistles, whistles with a greater beginning frequency than ending frequency were most common in Cook Inlet as was observed in a study of captive belugas (Fish and Mowbray 1962). As has been described in other beluga populations (Sjare and Smith 1986a, Angiel 1997, Karlsen et al. 2002, Belikov and Bel'kovich 2007, Chmelnitsky and Ferguson 2012, flattened whistles were common in Cook Inlet. ...
Cook Inlet beluga whales (CIBs) are an endangered population residing in Cook Inlet, Alaska. We characterized the calling behavior of CIBs to improve our understanding of sounds produced by this population. Bottom-moored hydrophones were deployed at Eagle Bay in summer 2009 and at Trading Bay in summer and winter 2009. CIB sounds were qualitatively analyzed and categorized as a whistle, pulsed call, or click train. A total of 4,097 calls were analyzed, and 66 unique whistle contours were identified. Whistles were quantitatively analyzed using a custom Matlab program. A chi-square test showed the call category usage at Eagle Bay during summer 2009 and those at Trading Bay during summer 2009 and winter 2009–2010 differed significantly (P < 0.001). Pulsed calls were more common during summer months, and click trains within the frequency band (12.5 kHz) were more common in Eagle Bay. The variation in calling behavior suggests differences in habitat usage or in the surrounding environment, including background noise. With the proposed development projects in Cook Inlet and the potential increase in ambient noise level due to ocean acidification, it is important to understand how this endangered population uses sound, and what anthropogenic factors may influence that use.
... Examples of wavy whistles in midand high-frequency bands are shown in Fig. 12 W5a, b, c. Trills are other types of wavy timefrequency contours, but with faster variations or a rapid succession of tonal components at slight frequency shifts (Fish and Mowbray 1962). Various types were encountered with either flat, descending, or ascending general contours (Fig. 12 W6). ...
Acoustic recordings from autonomous hydrophones were collected in the Mackenzie
Estuary within the Tarium Niryutait marine protected area (MPA) for 11 days in July 2011 and
34 days in June and July 2012. Data were analyzed to get the time-series of beluga occurrence
from their calls and to assess the underwater noise levels for a range of conditions. Results show
that belugas frequented the Estuary immediately after ice breakup and the Mackenzie flow
freshet peak. Coastal sea-surface temperatures in the Estuary were 5–10°C higher than the
adjacent offshore waters. Despite the low amplitude (< 0.5 m) of the local semidiurnal tides,
beluga frequentation in both years recurred with high water and was nil at low water. There was
no clear evidence of any systematic diurnal frequentation pattern. Alternating periods of
presence and absence on a 4–5 day cycle was noted in 2012. Temperature changes at the
monitoring stations were low and did not appear to influence beluga frequentation. Underwater
noise levels in the [0.2 to 16.4 kHz] band varied by ~15 to 30 dB depending on the
meteorological conditions and presence of a motor boat.
... Spectrogram settings included a 44 kHz sampling rate and a 1,024 point Hann window with 90 % overlap (Recordings courtesy of Ari Daniel Shapiro) et al. ( 2012 ). This work confi rmed earlier descriptive accounts of belugas producing speech-like sounds (e.g., Fish and Mowbray 1962 ). However, nothing is known regarding if or how belugas may use this vocal learning ability in their natural communication system. ...
The mammalian order Cetacea, which contains the whales, dolphins and porpoises, is a highly diverse group with respect to life history patterns, social structure, social behavior and communication. This chapter reviews what is known about communication in each of the 13 cetacean families, and includes discussions of some of the better known communicative signals, such as the songs of several baleen whale species, and the group- and individual-specific signals of killer whales and bottlenose dolphins. The apparent anti-predator adaptations seen in the vocalizations of several families are also discussed. Overall, there is a great need for basic research on how calls are used in the natural communication systems of most cetacean species. Such research promises to shed light on both applied (e.g., effects of anthropogenic noise) and basic (e.g., evolution of vocal learning) research questions. © 2014 Springer Science+Business Media Dordrecht. All rights are reserved.
... The repertoire of vocal sounds produced by belugas has been evaluated both in captive animals (Vergara & Barrett-Lennard, 2008) and wild populations (Chmelnitsky & Ferguson, 2012), and is historically considered to be one of the most varied of all cetaceans (Fish & Mowbray, 1962;Schevill & Lawrence, 1949). Like most toothed whales, they produce a wide range of pulsed sounds, many of which have been described as whistles or pulsed calls. ...
Vocal imitation is often described as a specialized form of learning that facilitates social communication and that involves less cognitively sophisticated mechanisms than more "perceptually opaque" types of imitation. Here, we present an alternative perspective. Considering current evidence from adult mammals, we note that vocal imitation often does not lead to learning and can involve a wide range of cognitive processes. We further suggest that sound imitation capacities may have evolved in certain mammals, such as cetaceans and humans, to enhance both the perception of ongoing actions and the prediction of future events, rather than to facilitate mate attraction or the formation of social bonds. The ability of adults to voluntarily imitate sounds is better described as a cognitive skill than as a communicative learning mechanism. Sound imitation abilities are gradually acquired through practice and require the coordination of multiple perceptual-motor and cognitive mechanisms for representing and generating sounds. Understanding these mechanisms is critical to explaining why relatively few mammals are capable of flexibly imitating sounds, and why individuals vary in their ability to imitate sounds. In his seminal text, Habitat and Instinct, Lloyd Morgan (1896, p. 166) describes two general kinds of imitation: instinctive imitation and intelligent or voluntary imitation. The examples he provides of intelligent imitation mostly involve reproducing sounds—a child copies words used by his companions, a mockingbird imitates the songs of 32 other bird species, a jay imitates the neighing of a horse, and so on. In fact, most of the examples of "imitation proper" Author Note: Preparation of this paper was made possible by NSF grant #SMA-1041755 to the Temporal Dynamics of Learn-ing Center, an NSF Science of Learning Center and NSF grant #BCS-1256864. We thank Sean Green, Emma Greenspon, and Benjamin Chin for comments on an earlier version of this paper.
... Traditionally, the vocalizations of toothed whales (Odontoceti) are classified based on the physical (time-frequency) characteristics of the sounds. In this case, the classification can be based on the auditory perception of the operator [1,8,19] or on the comparative analysis of the signal spectrograms [3,4,25]. However, the determination of the functional load is a very difficult problem. ...
The underwater vocalizations of the beluga whale summering in Onega Bay (64°24′N, 35°49′E) were recorded in June–July of 2008. The vocalizations were classified into five major whistle types, four types of pulsed tones, click series, and noise vocalizations. To determine the relationship between the behavioral activity and the underwater vocalizations, a total of fifty-one 2 minute-long samples of the audio records were analyzed in the next six behavioral contexts: directional movements, quiet swimming, resting, social interactions, individual hunting behavior, and the exploration of hydrophones by beluga whales. The overall vocalization rate and the percentage of the main types of signals depend on the behavior of the belugas. We suggest that one of the whistle types (the “stereotype whistle”) is used by belugas for long-distance communications, while other whistle types (with the exception of “squeaks”) and three types of pulsed tones (with the exception of “vowels”) are used for short distance communication. The percentage of “squeaks” and “vowels” was equally high in all the behavioral situations. Thus, we assume that “squeaks” are contact signals. “Vowels” have a specific physical structure and probably play a role in identification signals. A high rate of the click series was observed in the process of social interactions.
... Some authors (e.g., Recchia, 1994) assert that scant knowledge of the beluga's social behavior points towards some similarity to bottlenose dolphins or sperm whales in terms of fission-fusion patterns of association. It is known, however, that it is the most soniferous odontocete species, producing highly varied communication calls (Schevill & Lawrence, 1949;Fish & Mowbray, 1962;Sjare & Smith, 1986a, 1986bKarlsen et al., 2002) as well as possessing an unparalleled echolocation system (Au et al., 1985;Turl et al., 1987Turl et al., , 1991. This species uses the two predominant sound types among toothed whales: (1) whistles, or narrow-band, frequency modulated vocalizations, believed to be social signals, and (2) pulsed sounds, or trains of broadband pulses, including those used for echolocation. ...
Acoustic communication is central to the socio-ecology of cetaceans. Knowledge of the ontogeny of their extensive repertoires is scant, and even less is known about the role of learning in vocal development. To examine these issues, the development of calls of one male beluga (Delphinapterus leucas) calf was systematically studied at the Vancouver Aquarium throughout his first year of life and opportunistically through his second and third years. He vocalized within the first hour after birth, producing exclusively low energy, broadband pulse trains. Both the dominant frequency and the pulse repetition rate of the pulsed calls increased with age. He acquired rudimentary whistles at 2 wks of age. During the second month, whistle production increased substantially. Whistle dominant frequency tended to increase with age, and at least in his first year, whistles did not attain full stereotypy. The calf started using mixed call types consistently at 4 months. While some sounds tended to be more variable at later ages, his mixed calls progressively lost variability and increasingly resembled his mother’s most predominant stereotyped mixed call type. By 20 months, this call type was fully stereotyped. Six months after he was exposed to his father’s sounds, he incorporated one of his father’s call types into his repertoire. These findings are discussed in light of current theories of sound production mechanisms in odontocetes, developmental stages of vocal acquisition, and vocal learning.
... A few other authors have connected the banded structure with modulation or pulsing; but apparently have not recognized repetition-rate. Fish and Mowbray (1962) recognized one instance of side-band structure from Delphinapterus leucas as a possible indication of modulation, but did not note the connection between rate and harmonic interval in other sounds. Vincent (1960) said that a rapid click series sounded like "un miaulement", but did not take note of the repetition-rate information available in the spectrographic analysis. ...
Originally issued as Reference No. 68-13 The harmonic interval indicated during spectrographic analysis of a rapid train of pulses may be used to determine the pulse repetition-rate. If the pulse rate is regular, but too rapid to be separated, the repetition-rate may or may not be represented on such analysis as a line at the repetition frequency, but will always be indicated by the separation between harmonic bands, the harmonic interval. Office of Naval Research Contracts Nonr-4029 (00) NR 260-101 and Nonr-4446(00) NR 104-810.
Dolphins and whales are highly complex, large-brained social mammals. To date, thousands are kept in concrete tanks in marine parks and aquariums around the world. In these environments, they endure lack of control, lack of stimulation, and loss of the ability to engage in activities necessary for them to thrive. The fact that they are such complex, self-aware, intelligent beings makes it more difficult for them to cope in artificial environments, not less, as might be expected. This is because their needs cannot be met outside of their natural habitat. The only ethical response to this situation is to phase out the keeping of dolphins and whales for entertainment and to move those in commercial facilities to sanctuaries that prioritize their needs.
The playback of natural sounds has been used as an experimental technique with diverse groups of animals and with varied degrees of success to elucidate the biological significance of the sounds. Additionally, the playback of pure tones has been used to investigate which parameters of an acoustic signal are directly concerned with communication. Such parameters have included frequency limits of hearing, effectiveness of auditory masking, direction-finding and frequency discrimination capabilities, and intensity limits of frequency detection (audiograms).
Our understanding of ice-related underwater acoustic phenomena, characteristic of both arctic and subarctic environments, are briefly reviewed. The phenomenology of ambient noise generation and propagation in subarctic waters, being unique to the marginal sea/ice zone, are discussed in some detail. Recent investigations suggest that ocean wave-generated noise at the Arctic ocean-open ocean boundary can, under the proper circumstances, have very long range effects. Suggestions for future hydroacoustic research in subarctic waters are outlined.
The underwater vocalizations of white whales, Delphinapterus leucas, summering at Cunningham Inlet, N.W.T. (74°05′ N, 93°45′ W), were recorded from mid-July to mid-August 1983. Vocalizations were classified into one of eight major whistle contour types, one of four pulsed call categories including click series and three types of pulsed tones, and noisy vocalizations. To determine the relationship between vocalizations and behavioral activities, a total of sixty-three 2-min samples were recorded when whales were resting, swimming in a directive manner, socially interactive, and alarmed. Differences in the total number of whistles, pulsed tones (including noisy vocalizations), and click series emitted per whale/min during each behavioral activity were examined. The number of whistles emitted did not differ with changes in behavioral activity (χ2 = 5.42, df = 3, p = 0.143); however, the number of click series (χ2 = 31.85, df = 3, p = 0.0001) and the total number of pulsed tones emitted (χ2 = 7.33, df = 3, p = 0.062) did show distinct trends. More specific analyses considering each of the major whistle contour types, the three types of pulsed tones, and noisy vocalizations were also completed. The rate at which one type of whistle, two types of pulsed tones, and the noisy vocalizations were emitted was influenced by changes in behavioral activity. These results reveal a general association between white whale behavioral activity and the types of vocalizations emitted.
The underwater vocalizations of white whales, Delphinapterus leucas, summering at Cunningham Inlet, Northwest Territories, were recorded from mid-July to mid-August 1981 to 1983. A total of 807 tonal calls (whistles) were classified into 16 contour types. The following acoustic parameters were measured for each whistle: minimum, maximum, and mean frequency of the fundamental, contour or shape of the fundamental, duration, and the slope of the frequency changes during the call. Some 436 pulsed calls were classified into three major categories: click series, pulsed tones, and noisy vocalizations. Acoustic parameters measured for each of these calls included pulse repetition rate, range and mean frequency of the call, and duration. Results show that the whistle repertoire of white whales is more varied than has been previously reported. Mean frequencies for the whistle contour types ranged from 2.0 to 5.9 kHz; mean duration ranged from 0.25 to 1.95 s. Although whistles were the most commonly emitted type of vocalization, pulsed tones and noisy vocalizations made up a significant proportion of the white whales' vocal repertoire. The mean pulse repetition rate of pulsed tones ranged from 203.9 to 1289.0 pulses/s. There does not appear to be any between-year variation in the vocal repertoire of these white whales.
Contact calls are ubiquitous in social birds and mammals. Belugas are among the most vocal of cetaceans, but the function of their calls is poorly understood. In a previous study we hypothesized that a broad band pulsed call type labeled “Type A,” serves as a contact call between mothers and their calves. Here we examined context-specific use of call types recorded from a captive beluga social group at the Vancouver Aquarium, and found that the Type A call comprised 24% to 97% of the vocalizations during isolation, births, death of a calf, presence of external stressors, and re-union of animals after separation. In contrast it comprised 4.4% of the vocalizations produced during regular sessions. We grouped 2835 Type A calls into five variants, A1 to A5. A discriminant function analysis classified 87% of calls in the same groupings that we assigned them to by ear and visual examination of spectrograms. The variants do not represent individual signatures. One variant, A1, was used by three related individuals: an adult female, her male calf and his juvenile half-sister. Our previous research documented the gradual development of the A1 variant by the male calf, until at 20 months he was producing stereotyped renditions of his mother and sister’s A1. We used our findings to generate testable predictions about the usage of these signals by wild belugas. We verified the existence of signals with the same distinctive features as the contact calls found in captivity in the repertoire of St. Lawrence Estuary herds, and documented their usage by two wild individuals from different populations. In the St. Lawrence, these were emitted by a female calling after a dead-calf. In Hudson Bay, by a temporarily restrained juvenile. We propose that these calls function in nature, as in captivity, to maintain group cohesion, and that the variants shared by related animals are used for mother-calf recognition.
This article describes an automatic detector for marine mammal vocalizations. Even though there has been previous research on optimizing automatic detectors for specific calls or specific species, the detection of any type of call by a diversity of marine mammal species still poses quite a challenge--and one that is faced more frequently as the scope of passive acoustic monitoring studies and the amount of data collected increase. Information (Shannon) entropy measures the amount of information in a signal. A detector based on spectral entropy surpassed two commonly used detectors based on peak-energy detection. Receiver operating characteristic curves were computed for performance comparison. The entropy detector performed considerably faster than real time. It can be used as a first step in an automatic signal analysis yielding potential signals. It should be followed by automatic classification, recognition, and identification algorithms to group and identify signals. Examples are shown from underwater recordings in the Western Canadian Arctic. Calls of a variety of cetacean and pinniped species were detected.
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