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Sounds produced by individual white whales, Delphinapterus leucas, from Svalbard during capture (L)

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Sofie Van Parijs at National Oceanic and Atmospheric Administration
Sofie Van Parijs
Christian Lydersen at Norwegian Polar Institute
Christian Lydersen
Kit M. Kovacs at Norwegian Polar Institute
Kit M. Kovacs
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Abstract and Figures

Recordings were made of the sounds produced by white whales during capture events in Storfjorden, Svalbard, in the late autumn. Only four of eight captured individuals produced sounds. Four subadults, one female and three males, between 330 and 375 cm long, did not produce sounds during handling. The four animals that produced sounds were as follows: a female subadult of 280 cm produced repetitive broadband clicks; a solitary calf produced harmonic sounds, which we suggest may serve as mother-calf ``contact calls,'' and a mother-calf pair were the two animals that produced the most sounds in the study. The mother produced ``crooning'' broadband clicks and frequently moved her head toward her calf while producing underwater sounds. The calf produced three types of frequency-modulated sounds interspersed within broadband click trains. No sounds were heard from any of the animals once they were free-swimming, or during ad lib recording sessions in the study area, even though groups of white whales were sighted on several occasions away from the capture net.
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Sounds produced by individual white whales, Delphinapterus
leucas, from Svalbard during capture (L)
Sofie M. Van Parijs,
a)
Christian Lydersen, and Kit M. Kovacs
Norwegian Polar Institute, N-9296 Tromsø, Norway
共Received 28 February 2002; revised 2 May 2002; accepted 1 October 2002兲
Recordings were made of the sounds produced by white whales during capture events in
Storfjorden, Svalbard, in the late autumn. Only four of eight captured individuals produced sounds.
Four subadults, one female and three males, between 330 and 375 cm long, did not produce sounds
during handling. The four animals that produced sounds were as follows: a female subadult of 280
cm produced repetitive broadband clicks; a solitary calf produced harmonic sounds, which we
suggest may serve as mother–calf ‘‘contact calls,’’and a mother–calf pair were the two animals that
produced the most sounds in the study. The mother produced ‘‘crooning’’ broadband clicks and
frequently moved her head toward her calf while producing underwater sounds. The calf produced
three types of frequency-modulated sounds interspersed within broadband click trains. No sounds
were heard from any of the animals once they were free-swimming, or during ad lib recording
sessions in the study area, even though groups of white whales were sighted on several occasions
away from the capture net. © 2003 Acoustical Society of America. 关DOI: 10.1121/1.1528931兴
PACS numbers: 43.80.Ka, 43.40.Dx, 43.70.Bk 关WA兴
I. INTRODUCTION
White whales, Delphinapterus leucas, produce a wide
range of variable underwater sounds 共e.g., Sjare and Smith,
1986a, b; Bel’kovich and Sh’ekotov, 1992, 1993兲. These
sounds have been shown to vary according to behavioral
context 共e.g., Sjare and Smith, 1986a, b; Bel’kovich and
Sh’ekotov, 1992, 1993兲; a variety of studies have linked in-
dividual signals with specific behaviors and group contexts
共Morgan, 1979; Bel’kovich and Sh’ekotov, 1992, 1993兲.
However, few studies have studied the sounds produced by
individual whales 共e.g., Au and Nachtigall, 1997兲. Given the
complexity of white whale sounds, further investigations of
this kind are necessary to improve our understanding of
sound usage in this species. White whales are thought to alter
their calling behavior in response to the presence of vessels
共Finley et al., 1990; Lesage et al., 1999兲 and a variety of
cetacean species have been shown to produce ‘‘contact calls’’
during stressful situations 共Caldwell et al., 1990兲. The aim of
this study was to investigate the sounds produced by indi-
vidual white whales during capture.
II. METHODS
This study was carried out between 17 and 23 October
2001 at Wichebukta in Storfjorden 共78°31
⬘
N, 18°55
⬘
E兲, east-
ern Spitsbergen. White whales were captured using a net set
from the beach and the sex and age of all individuals were
determined 关see Lydersen et al. 共2001兲 for more details兴. The
whales were captured for the purpose of deploying satellite
transmitters. During the handling process continuous record-
ings were made of the sounds of each captured whale. A
hydrophone was placed 0.5 m deep in the water in front of
the head of each individual and recordings were made of any
sounds that were produced during handling and upon release.
Recordings of the sounds were made using a High Tech Inc.
hydrophone 共model HTI-96-MIN, sensitivity: ⫺170 dB, flat
frequency response: 5 Hz to 30 kHz; add ⫾1.0 dB兲 and a
digital audio tape recorder, Sony TCD-D8 共frequency re-
sponse 5 Hz to 22 kHz ⫾1.0 dB兲. The recordings were digi-
tized and displayed as spectrograms 共fast Fourier transforms,
dt: 10 ms, df: 102 Hz, FFT size: 512兲 using the BatSound
analysis PC software program 共Pettersson Elektronik A.B.,
1996兲.
Sounds were divided into two broad categories, broad-
band clicks and narrow-band frequency-modulated sounds.
Frequency-modulated sound types were defined according to
variations in their spectral contours. Only high-quality
records, where all sound contours were distinctly measurable
on the spectrograms, were used for these analyses. Two
sound parameters were measured for burst pulses and
narrow-band frequency modulated sounds: 共1兲 total duration
共s兲 and 共2兲 frequency with the greatest energy, Fmax 共kHz兲.
For broadband clicks four measurements were made: 共1兲 the
duration of the click train 共s兲; 共2兲 the interclick interval ICI
共s兲, 共3兲 number of clicks per seconds, and 共4兲 the interval
between one click train and the next, BCI 共s兲. Measurements
were restricted by the upper limit 共22 kHz兲 of the recording
equipment.
Ad lib recordings were made each day during the study
period, from a zodiac that was adrift several hundred meters
offshore in the bay in which the net was set.
III. RESULTS
Eight whales were captured during the study period: five
were subadults, one mother–calf pair was captured, and one
solitary calf. Four of the five subadults 共one female and three
males兲 did not produce any sounds. These animals were all
a兲
Author to whom correspondence should be addressed. Sofie Van Parijs,
Norwegian College of Fisheries Science, University of Tromsø, 9037
Tromsø, Norway. Electronic mail: sofievp@nfh.uit.no
57J. Acoust. Soc. Am. 113 (1), January 2003 0001-4966/2003/113(1)/57/4/$19.00 © 2003 Acoustical Society of America
more than 320 cm in length. A mother–calf pair, a solitary
calf and, a subadult that was 280 cm long each produced
sounds. All of these whales were females.
Sounds produced by the solitary calf were distinct from
all other sounds recorded in this study, in that they contained
frequency-modulated calls. There were two distinct sounds,
harmonic 1 and 2 共Fig. 1兲. The calf produced sounds for 66%
of the handling time (n⫽ 24 min). Harmonic 1 (n⫽ 108) had
a mean duration of 0.7⫾0.01 SE s, with a mean Fmax of
3.3⫾0.07 SE kHz. Harmonic 2 (n⫽ 39) had a mean duration
of 0.4⫾0.01 SE and a mean Fmax of 1.5⫾0.2 SE. During
production of this sound air was expelled by the calf through
its blowhole.
The mother–calf pair were kept in close contact with
one another throughout their handling time. The mother pro-
duced sounds 79% of the time and the calf produced sounds
43% of the time (n⫽ 35 min). The sounds produced by the
mother were composed of repetitive click trains that varied
greatly in duration 共mean 1.9⫾1.3 SE s, n⫽ 339) 共Fig. 2兲.
ICI varied from 0.46 to 0.012 s in duration with a mean of 27
clicks produced per second (n⫽ 241). The mean BCI was
1.5⫾1.1 SE s (n⫽ 235). The click trains produced by the
mother had a distinct audible ‘‘crooning’’ sound. The female
frequently moved her head toward the calf while producing
underwater sounds. The calf from the mother–calf pair pro-
duced click trains (n⫽ 206) and occasional frequency-
modulated sounds within the click trains (n⫽ 32) 共Fig. 3兲.
The calf’s click trains had a mean duration of 0.6⫾0.5 SE s.
ICI varied from 0.5 to 0.09 s in duration, with a mean of 18
clicks per second. The mean BCI was 6.5⫾1.3 SE s (n
⫽ 153). This calf produced three types of frequency-
modulated sounds, all of which occurred with either one or
no harmonics 共Fig. 3兲: a flat contour (n⫽ 18), an upsweep
(n⫽ 9), and a variable contour (n⫽ 5). The mean duration
of the flat contour whistle was 0.4⫾0.05 SE s, with the mean
frequency of the first harmonic at 7.6⫾0.3 SE kHz and the
second harmonic of 15.1⫾0.1 SE kHz. Upsweep whistles
were 0.3⫾0.03 SE s in duration and 7.9⫾0.02 SE kHz in the
first harmonic and 15.0⫾0.08 SE kHz in the second har-
monic. Variable contour whistles were considerably longer in
duration 共mean of 1.2⫾0.9 SE s兲, but had a comparable
Fmax of 7.7⫾0.3 SE kHz in the first harmonic and 15.1⫾0.3
SE kHz in the second harmonic. The subadult female pro-
duced only click trains 共Fig. 4兲. A total of 37 min were re-
corded for this animal, during which the subadult produced
sounds 28% of the time. The click trains had a mean duration
of 0.3⫾0.08 SE s (n⫽ 89). ICI varied from 0.41 to 0.03 s in
duration with a mean of 22 clicks per second. The mean BCI
was 11.5⫾2.7 SE s (n⫽ 153).
A total of7hofad lib recordings were made from a
drifting zodiac. Even though whales passed close to the boat
on several occasions, no white whales sounds were recorded
from any free-swimming individuals.
IV. DISCUSSION
This study has shown that individual white whales pro-
duce a variety of different sounds during a similar, stressful
situation. Surprisingly, subadults of more than 320 cm in
length did not produce any sounds under 22 kHz, while be-
ing held in a net and manipulated. Although it is possible that
subadults produced ultrasonic sounds, during this and in
other studies, the majority of sounds produced by white
whales have either a part or the whole component that occurs
below 22 kHz 共e.g., Sjare and Smith, 1986a, b; Bel’kovich
and Sh’ekotov, 1992, 1993兲. Among the subadults that did
FIG. 1. Spectrograms of the harmonic sounds 1 and 2 produced by the
solitary female calf 共fast Fourier transforms, dt:10ms,df: 102 Hz, FFT
size: 512兲. The gaps in the time scale on the x axis represent the start and
end of each spectrogram.
FIG. 2. Spectrograms of the broadband clicks and burst pulsed sounds pro-
duced by the adult female from the mother–calf pair 共fast Fourier trans-
forms, dt:10ms,df: 102 Hz, FFT size: 512兲. The gaps in the time scale on
the x axis represent the start and end of each spectrogram.
58 J. Acoust. Soc. Am., Vol. 113, No. 1, January 2003 Van Parijs
et al.
: Letters to the Editor
not produce sounds, there were one female and three males,
therefore it is unlikely that this result is related to variation in
sex. It is more likely that it is related to age. The single
subadult that did produce sounds was 280 cm in length, sug-
gesting it was between three and four years of age 共Heide-
Jørgensen and Teilmann, 1994兲. The sounds that it produced
were solely broadband clicks. Click series, as defined by
Sjare and Smith 共1986a兲, are used most frequently during
‘‘socially interactive’’ or ‘‘alarm situations.’’ The click series
produced by this individual in this study resembled the
broadband clicks observed in Sjare and Smith 共1986a兲.
The solitary calf produced sounds that were different
from those recorded for other individuals. Similar sounds to
this harmonic call have been documented in the repertoires
of wild ranging white whales 共Sjare and Smith, 1986a;
Bel’kovich and Sh’ekotov, 1992, 1993兲. The size of this in-
dividual suggests that it was one to two years old and there-
fore still likely to have been dependent on its mother.
Mother–calf whistles are produced in Tursiops sp. and have
been shown to facilitate reunions between mother–calf pairs
共e.g., Smolker et al., 1993兲. It is possible that the sounds
produced by the calf were a mother–calf contact call pro-
duced during separation. The adult female of the mother–
calf pair produced broadband clicks. The behavior of the
mother suggested that these sounds were directed toward her
calf. Bel’kovich and Sh’ekotov 共1992兲 show spectrographs
of sounds produced by mother–calf pairs, some of which
resemble those produced in this study. However, the sounds
used by the mother–calf pair in this study differ significantly
from the whistles reported in many delphinid mother–calf
contact behaviors 共Smolker et al., 1993兲.
The fact that only young animals and members of a
mother–calf pair produced sounds during capture suggests
that previously described ‘‘alarm calls’’ 共Finley et al., 1990;
Lesage et al., 1999兲 may actually be contact calls between
mothers and dependent young. No sounds were recorded
from free-swimming whales, although groups were sighted
in the area where boats were operating. Additionally, no
sounds were produced from males or large juveniles that
were captured, presumably in a ‘‘stressful’’ situation. Unlike
many delphinid species 共Caldwell et al., 1990兲, the white
whales in this study did not produce a standard ‘‘contact
call.’’ The sounds produced by individual animals during
handling were variable, but the age/status of animals emit-
ting calls and their structure suggest that it is likely that they
all served as ‘‘contact calls.’’
ACKNOWLEDGMENTS
We thank Magnus Andersen, Guttorm Christensen,
Colin Hunter, Øle Anders Nøst, Morten Tryland, Masa Tet-
suka, and Hans Wolkers for their assistance in capturing the
whales. This study was supported by funds from the Norwe-
gian Polar Institute 共NPI兲. SVP was funded via a European
Union Marie Curie Postdoctoral Fellowship. Ethical ap-
proval was obtained from the Norwegian Animal Care Au-
thority, and the Environmental Office of the Governor of
Svalbard issued permits for this work.
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: Letters to the Editor
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Article
  • Jul 2019
Pacific white-sided dolphins are a group-living species and appear to exchange “contact calls” to maintain group cohesion. The aim of this study was to find and characterize their contact calls. Calls were recorded from two females at Osaka Aquarium KAIYUKAN (OAK) and three females at Izu-Mito Sea Paradise (IMSP). Because they often produced pulsed calls consecutively, a “pulsed call sequence” was defined as three or more successive pulsed calls occurring within 325 ms, which was calculated using a bout analysis. The pulsed call sequences increased during separation periods and decreased during reunions and were used for vocal exchange, suggesting that the sequences are contact calls in Pacific white-sided dolphins. Most of the pulsed call sequences were classified into unique types; several stereotyped, repeated patterns were found. One sequence type was found at OAK and the two dolphins shared the type; they exchanged sequences with type matching. On the other hand, three sequence types were found in IMSP and the three dolphins shared all of the types; however, each dolphin preferentially used different types and frequently exchanged with their own favorite types but not with type matching. These results suggest that the sequence type may function as an individual and/or group identity.
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... It is important to note that while some species emit alarm calls frequently when facing predators or other potential threats, others may become less vocal or even silent (90,91). For example, when both free-ranging and professionallymanaged beluga whales (Delphinapterus leucas) are exposed to predators or noise disturbances (e.g., killer whales, boat engines), their acoustic activity may decrease or cease completely (62,(92)(93)(94). Similar results have been found for free-ranging narwhals (Monodon monoceros), suggesting that it may be adaptive for marine mammals to reduce or eliminate vocal activity when encountering potential threats (95). ...
Utilizing vocalizations to gain insight into the affective states of non-human mammals
Article
Full-text available
  • Feb 2024
This review discusses how welfare scientists can examine vocalizations to gain insight into the affective states of individual animals. In recent years, researchers working in professionally managed settings have recognized the value of monitoring the types, rates, and acoustic structures of calls, which may reflect various aspects of welfare. Fortunately, recent technological advances in the field of bioacoustics allow for vocal activity to be recorded with microphones, hydrophones, and animal-attached devices (e.g., collars), as well as automated call recognition. We consider how vocal behavior can be used as an indicator of affective state, with particular interest in the valence of emotions. While most studies have investigated vocal activity produced in negative contexts (e.g., experiencing pain, social isolation, environmental disturbances), we highlight vocalizations that express positive affective states. For instance, some species produce vocalizations while foraging, playing, engaging in grooming, or interacting affiliatively with conspecifics. This review provides an overview of the evidence that exists for the construct validity of vocal indicators of affective state in non-human mammals. Furthermore, we discuss non-invasive methods that can be utilized to investigate vocal behavior, as well as potential limitations to this line of research. In the future, welfare scientists should attempt to identify reliable, valid species-specific calls that reflect emotional valence, which may be possible by adopting a dimensional approach. The dimensional approach considers both arousal and valence by comparing vocalizations emitted in negative and positive contexts. Ultimately, acoustic activity can be tracked continuously to detect shifts in welfare status or to evaluate the impact of animal transfers, introductions, and changes to the husbandry routine or environment. We encourage welfare scientists to expand their welfare monitoring toolkits by combining vocal activity with other behavioral measures and physiological biomarkers.
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... To date, no comparative studies have been conducted to determine the presence of geographical variation in signals with a known function, such as the long duration broadband contact calls described in the literature for various populations (Mishima et al., 2015;Morisaka et al., 2013;Van Parijs et al., 2003;Vergara et al., 2010). ...
Geographic variation in simple contact calls of Canadian beluga whales (Delphinapterus leucas )
Article
  • Dec 2023
Beluga whales, Delphinapterus leucas , are a highly social species with a complex and diverse vocal repertoire. Although extensively studied and classified, to date few attempts have been made to examine geographic variation in their calls. In this study, we examined geographic variation in simple contact calls (SCCs), specifically those that consist only of broadband pulsed trains, among four Canadian beluga populations from the Eastern Beaufort Sea (EBS), the Eastern High Arctic‐Baffin Bay, St. Lawrence Estuary (SLE), and the Western Hudson Bay. Five acoustic parameters were measured for each call and compared among populations using multivariate discriminant analysis. Results of our study indicate that there is a degree of variation in SCCs among these four populations, with the most geographically distant populations of the SLE and EBS displaying the greatest degrees of dissimilarity in SCC structure relative to geographically closer populations. Further, these results align with genetic variation of Canadian beluga populations previously described in the literature. This study is the first descriptive population comparison of SCCs for beluga and establishes a baseline for continued work into this developing area of research.
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... Calls used for this specific purpose are referred to as contact calls, some of which may possibly encode individual or group identity (Vergara and Mikus, 2019). The use of contact calls between group members has been studied in belugas in both aquaria and the wild (Mishima et al., 2015;Mishima et al., 2018;Morisaka et al., 2013;Panova et al., 2017;Panova and Agafonov, 2023;Van Parijs et al., 2003;Vergara et al., 2010;Vergara and Mikus, 2019). The use of individual identity and group cohesion calls has been extensively studied in delphinids, particularly in bottlenose dolphins, which are known to produce highly stereotyped signature whistles containing individual identity and broadcast information about the caller (Caldwell and Caldwell, 1965;Janik et al., 2006;Janik and Slater, 1998;Sayigh et al., 1999). ...
Communication in Cook Inlet beluga whales: Describing the vocal repertoire and masking of calls by commercial ship noise
Article
Full-text available
  • Nov 2023
  • J ACOUST SOC AM
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.
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... Similarly, contact calls comprised only 4.4% of all calls produced by a captive beluga group during regular sessions but were predominant (up to 97%) vocalizations in particular contexts such as birth or death of a calf, forced and voluntary isolation, presence of external stressors, and reunion of animals (Vergara et al., 2010). Among eight belugas temporarily restrained in Storfjorden, Svalbard, only one female subadult, a solitary calf, and a mother-calf pair produced sounds, which were interpreted as contact calls, while four larger subadults, one female and three males, did not vocalize during handling (Van Parijs et al., 2003). ...
Possible occurrence of contact calls in all‐male groups of free‐ranging beluga whales
Article
  • Feb 2023
Social toothed whales are known to produce specific vocalizations that may serve for individual or group recognition and maintaining cohesion among group members. In beluga whales Delphinapterus leucas , these vocalizations referred to as “contact calls” are relatively long duration, repeated stereotyped broadband sounds. Although these calls are thought to be critical in mother‐calf communication, they are utilized by individuals of different ages and sex. We investigated possible occurrence of contact calls in all‐male beluga groups from the White Sea, Russia. Among the vocalizations analyzed ( n = 1169), a considerable proportion (58%) appeared to be potential contact calls. They were subjectively classified into 61 types of mostly complex broadband sounds combined with a narrow band element. The positive linear relationship ( R ² = 0.90) between the number of unique call types identified in the recordings and the number of belugas observed in the research area suggests that the calls serve as individual signatures. Belugas tended to produce these calls in a series, with the intercall intervals between the same and different call types mainly >1 s and <1 s, respectively. This suggests that vocal exchange by individually distinctive calls, like those of captive belugas and some other social species, might take place. The current study provides more insight into contact call usage in wild belugas and may serve as a basis for long‐term monitoring of their seasonal occurrence, abundance, and site fidelity, as well as for investigating their social organization.
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... They are often described as "sea canaries," because their sounds are comparable to songbirds' calls, especially when heard in ships (Kleinenberg et al., 1969;Slijper, 1962). Moreover, they are known to emit a large variety of sounds (Belikov & Bel'kovich, 2008;Chmelnitsky & Ferguson, 2012;Fish & Mowbray, 1962;Karlsen et al., 2002;Slijper, 1962;Van Parijs et al., 2003). Their click sounds are thought to have evolved in the Arctic environment where they live (Turl et al., 1991). ...
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Beluga (D. leucas), harbor porpoise (P. phocoena), and killer whale (O. orca) acoustic presence in Kotzebue Sound, Alaska: Silence speaks volumes
Article
Full-text available
  • Aug 2022
Prior to 1984, belugas (Delphinapterus leucas) were seen in large numbers in Kotzebue Sound, Alaska, during spring and summer and provided an important subsistence resource to coastal residents. Sightings and harvest declined sharply beginning in 1984: the average annual harvest dropped from 84/yr (1977-1983) to 16/yr (1984-2021). To examine this shift in beluga presence, passive acoustic moorings were deployed in summer 2013 and year-round in 2014-2016, to describe the seasonal and geographic occurrence of belugas. Three moorings were deployed off Cape Krusenstern, northwestern Kotzebue Sound, to monitor cetaceans traveling nearshore. A mooring was also deployed near Chamisso Island, southeastern Kotzebue Sound. We used automatic detectors to process the recordings for echolocation and tonal signals, and all detections were manually validated. Belugas, harbor porpoises (Phocoena phocoena), and transient killer whales (Orcinus orca) were detected in both areas, primarily from June to November. Detections extended into early winter for belugas, and sporadic detections were confirmed for porpoises from January to March. Belugas were detected on a total of 20 days, killer whales on 96 days, and porpoises on 179 days. The only beluga detections were echolocation signals. The absence of social signals likely reflects an anti-predator response to the presence of hunters and transient killer whales. Killer whale detections were composed of echolocation signals, limited to very short click trains, double clicks, and single clicks, a known cryptic acoustic behavior used when targeting prey. Killer whales also emitted high frequency whistles (17-51 kHz) providing the first evidence of this type of signals for transients. Our results suggest transient killer whales in predation mode scouting typical beluga habitat, concurrent with belugas in silent anti-predation mode. This anti-predation acoustic behavior was also evident outside the killer whale season, conveying a continued perception of predation risk for this habitat. If the increase in transient killer whale presence in Arctic waters is also taking place in Kotzebue Sound, the combined natural and anthropogenic predation pressure sustained by this habitat could be playing an important role in the continued low occurrence of beluga, with a consequent impact to the subsistence communities that rely on this species.
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Growth, reproduction, age structure and feeding habits of white whales (Delphinapterus leucas) in West Greenland waters
Article
Full-text available
  • Apr 1994
Reproductive organs, mandibular teeth, stomach contents and body measurements including total mass from white whales (Delphinapterus leucas) taken by Inuit hunters in West Greenland during 1985-1992 were analysed. Both sexes of white whales from West Greenland attain a greater length at physical maturity than do white whales from Alaska, Hudson Bay, northern Quebec, the White Sea and the Kara Sea. Male white whales attain sexual maturity at 6-7 years. Size of testes and presence of spermatozoa suggest that mating takes place in May or perhaps later. Female white whales apparently become sexually mature at 4 to 7 years of age, but the negative bias of age estimates from whales whose teeth lack the neonatal line confounded our effort to estimate the age at sexual maturity. Gestation lasts at least 330 days, with implantation in May- June, and calves are likely to be born in April-May.
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The effect of vessel noise on the vocal behavior of Belugas in the St. Lawrence River estuary, Canada
Article
Full-text available
  • Jan 1999
  • MAR MAMMAL SCI
A bstract During June‐July 1991, we monitored the vocal behavior of belugas before, during, and after exposure to noise from a small motorboat and a ferry to determine if there were any consistent patterns in their vocal behavior when exposed to these two familiar, but different sources of potential disturbance. Vocal responses were observed in all trials and were more persistent when whales were exposed to the ferry than to the small boat. These included (1) a progressive reduction in calling rate from 3.4–10.5 calls/whale/min to 0.0 or <1.0 calls/whale/min while vessels were approaching; (2) brief increases in the emission of falling tonal calls and the theree pulsed‐tone call types; (3) at distances <1 km, an increase in the repetition of specific calls, and (4) a shift in frequency bands used by vocalizing animals from a mean frequency of 3.6 kHz prior to exposure to noise to frequencies of 5.2‐8.8 kHz when vessels were close to the whales.
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Use of signature whistles during separations and reunions by wild bottlenose dolphin mothers and infants
Article
Full-text available
  • Dec 1993
We examine the contexts and patterns of “signature” whistle production by wild bottlenose dolphin mother-infant pairs (Tursiops spp.) to gain insight into the functional significance of whistles. Results are based on focal observations and simultaneous recordings of underwater vocalizations. Whistles occur primarily when mother-infant pairs are separated, and the probability of whistles increases with distance of separation. The timing of whistles during separations varies, but whistles tend to be produced in repetitive series and are generally concentrated toward the later stages of the separation, i.e., during the process of reunion. Although we focused on infants, mothers do not appear to whistle during separations as frequently as infants. Infant whistles may function to facilitate reunions by conveying information to the mother concerning the infant's motivation to reunite and/or its location. Infant whistles could induce a cooperative response from the mother including approach, slowing to allow the infant to catch up or whistling. Highly individualized signature whistles may be particularly useful in a fission-fusion society in which individuals (mothers and infants as well as adults) join and leave temporary parties in a fluid manner, yet maintain consistent, long-term associations with particular individuals. Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/46899/1/265_2004_Article_BF00170254.pdf
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Summer and autumn movements of white whales Delphinapterus leucas in Svalbard, Norway
Article
  • Sep 2001
Fifteen adult white whales Delphinapterus leucas were fitted with satellite relay data loggers (SRDLs) in order to study their distribution and movement patterns in Svalbard. A total of 844 d of tracking data was recorded. The average longevity of the SRDLs was 56 +/- 30 (SD) d (range 7 to 120 d). The tracking data were analysed using a computer visualisation system, which allowed the movement patterns to be animated against a background map of the study area. This enabled classification of the whales' tracking data into 4 major activity patterns: (1) glacier front stationary (55.6 % of the time), (2) in-fjord movements (10.6 % of the time), (3) coastal movements (26.0 % of the time), and (4) coastal stationary (7.8 % of the time), The whales spent most of their time relatively stationary, close to different glacier fronts in the area. These areas are known to have a high abundance of potential prey species for white whales, so foraging is the probable reason for this behaviour. When the whales changed location, they did so in an apparently directed and rapid manner., Average horizontal swimming speed was at least 6 km h(-1) during long-distance movements. Movements between glacier fronts were extremely coastal in nature and took place in shallow waters. This behaviour has probably developed as a means of avoiding predators.
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The relationship between behavioral activity and underwater vocalizations of the white whale, Delphinapterus leucas
Article
  • Feb 2011
  • CAN J ZOOL
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.
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The vocal repertoire of white whales, Delphinapterus leucas, summering in Cunningham Inlet, Northwest Territories
Article
  • Feb 2011
  • CAN J ZOOL
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.
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Acoustics of echolocating dolphins and small whales
Article
  • Aug 1997
One of the most effective methods for an animal to probe an underwater environment for the purpose of navigation, obstacle and predator avoidance, and prey detection is by the use of underwater sounds or acoustic signals. Dolphins and small whales emit sounds and analyze returning echoes to detect and recognize objects underwater, a process referred to as echolocation. We will first discuss the acoustic reception system of dolphins and consider topics such as auditory sensitivity, spectral analysis capabilities and directional hearing. We will then focus on the acoustic transmission system of dolphins, discussing topics such as properties of echolocation signals and propagation of the echolocation signals from the animals’ head.Dolphins echolocate by emitting high intensity broadband acoustic pulses in a directional beam and listening to echoes reflected from objects in their environment. Echolocation studies on three species, the Atlantic bottlenose dolphin (Tursiops truncatus), white whale (Delphinaterus leucas), and false killer whale (Pseudorca crassidens) have been conducted extensively in Kaneohe Bay, Oahu, Hawaii. Measurements of dolphin echolocation signals in the open waters of Kaneohe Bay indicate that the signals are of short duration (less than 50–70 us), high intensity (up to 230dB re 1 μPa peak‐to‐peak), broadband (30–40 kHz 3‐dB bandwidth) and of high frequency (peak frequencies between 100 and 130 kHz). Evidence indicates that the frequency of the signals may be controlled by intensity, with high intensity signals having high peak frequencies. Echolocation signals are emitted in a beam that is directed forward in the horizontal plane for Tursiops and Delphinaplerus, upwards at an angle of 5 to 10° in the vertical plane. The vertical beam of Pseudorca is directed between 0° and –5° downward. All three species use a pulse mode of transmission in which the repetition rate of the signal is adjusted so that the desired echoes are received before another pulse is transmitted.
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The vocal and behavioral reactions of beluga, Del-phinapterus leucas, to playback of its sounds
  • 391-423
  • D W Morgan
  • ͑1979͒
Morgan, D. W. ͑1979͒. ''The vocal and behavioral reactions of beluga, Del-phinapterus leucas, to playback of its sounds,'' in Behavior of Marine Animals: Current Perspectives in Research, edited by H. E. Winn and B. L. Olla ͑Plenum, New York͒, pp. 391– 423.