A quantitative and comparative analysis of the acoustic whistles parameters of tucuxi dolphins (Sotalia fluviatilis) from eight areas in Brazilian waters were conducted. Tucuxi produced mainly upsweep whistles, and despite their similar characteristics to other delphinids, whistles were shorter and less complex in shape. Some signals had fundamental frequency components above 24 kHz, and a broader band system may be useful in further studies concerning tucuxi whistles. The frequency parameters of the whistles had the lowest variation coefficients, whereas the duration and number of inflections had the highest variation coefficients. About 65% of all whistles had common characteristics between study localities, but SF, MinF, MeF, F1/4, F1/2, and F3/4 increased in frequency from southern to northern populations. The magnitude of the whistle characteristics variation was comparatively smaller between adjacent sites areas than between nonadjacent ones. However, for some pairwise comparisons the whistles were more similar between nonadjacent areas than between adjacent ones, indicating that other factors besides genetic and mixing affected tucuxi whistle characteristics. Only a few numbers of whistle variables were significantly different between adjacent areas and the parameter ranges of whistles overlapped, which made it difficult to discriminate whistles between adjacent tucuxi populations.

1.
Alcuri
,
G.
, and
Busnel
,
R. G.
(
1989
). “
Unicité functionelle des clics sonar et des sifflements dans les emissions acoustiques d’un Dauphin Amazonien S. fluviatilis Gervais et Deville
,”
C. R. Acad. Sci. Paris.
308
,
379
384
.
2.
Au
,
W. W. L.
,
Lammers
,
M. O.
, and
Aubauer
,
R.
(
1999
). “
A portable broad-band data acquisition system for field studies in bioacoustics
,”
Marine Mammal Sci.
15
,
526
531
.
3.
Azevedo, A. F. (2000). “Emissões sonoras do boto-cinza (Sotalia fluviatilis Gervais, 1853) na Baı́a de Guanabara—RJ,” Master thesis, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil.
4.
Azevedo
,
A. F.
, and
Simão
,
S. M.
(
2002
). “
Whistles produced by marine tucuxi dolphins (Sotalia fluviatilis) in Guanabara Bay, southeastern Brazil
,”
Aquat. Mamm.
28
,
261
266
.
5.
Bazúa-Duran
,
M. C.
, and
Au
,
W. W. L.
(
2002
). “
Whistles of Hawaiian spinner dolphins
,”
J. Acoust. Soc. Am.
112
,
3064
3072
.
6.
Bazúa-Duran
,
M. C.
(
2004
). “
Differences in the characteristics and repertoire of bottlenose and spinner dolphins
,”
Ann. Braz. Acad. Sci.
76
,
386
392
.
7.
Bazúa-Duran
,
M. C.
, and
Au
,
W. W. L.
(
2004
). “
Geographic variations in the whistles of spinner dolphins (Stenella longirostris) of the Main Hawaiian Islands
,”
J. Acoust. Soc. Am.
116
,
3757
3769
.
8.
Caldwell
,
M. C.
, and
Caldwell
,
K. D.
(
1970
). “
Echolocation-type signals by two dolphins, genus Sotalia
,”
Q. J. Fla. Acad. Sci.
33
,
124
131
.
9.
Cunha, H. A. (2003). “Distribuição e diversidade das linhagens de DNA mitocondrial do ecótipo marinho de Sotalia fluviatilis (Cetacea: Delphinidae),” Master’s thesis, Universidade do Estado do Rio de Janeiro, Brazil.
10.
Da Silva
,
V. M. F.
, and
Best
,
R. C.
(
1996
). “
Sotalia fluviatilis
,”
Mammalian Species
527
,
1
7
.
11.
Erber
,
C.
, and
Simão
,
S. M.
(
2004
). “
Analysis of whistles produced by the tucuxi dolphin Sotalia fluviatilis from Sepetiba Bay, Brazil
,”
Ann. Braz. Acad. Sci.
76
,
381
385
.
12.
Flores, P. A. C. (2002). “Tucuxi Sotalia fluviatilis,” in Encyclopedia of Marine Mammals, edited by W. F. Perrin, B. Wursig, and J. G. M. Thewissen (Academic Press, San Diego), pp. 1267–1269.
13.
Kamminga
,
C.
,
Van Hove
,
M. T.
,
Engelsma
,
F. J.
, and
Terry
,
R. P.
(
1993
). “
Investigations on cetacean sonar X: A comparative analysis of underwater echolocation clicks of Inia spp. and Sotalia spp.
,”
Aquat. Mamm.
19
,
31
43
.
14.
Matthews
,
J. N.
,
Rendell
,
L. E.
,
Gordon
,
J. C. D.
, and
MacDonald
,
D. W.
(
1999
). “
A review of frequency and time parameters of cetacean tonal calls
,”
Bioacoustics
10
,
47
71
. 21
15.
Monteiro-Filho
,
E. L. A.
, and
Monteiro
,
K. D. K. A.
(
2001
). “
Low-frequency sounds emitted by Sotalia fluviatilis guianensis (Cetacea: Delphinidae) in an estuarine region in southeastern Brazil
,”
Can. J. Zool.
79
,
59
66
.
16.
Monteiro-Filho
,
E. L. A.
,
Monteiro
,
L. R.
, and
Reis
,
S. F.
(
2002
). “
Skull shape and size divergence in dolphins of the genus Sotalia: a tridimensional morphometric analysis
,”
J. Mammal.
83
,
125
134
.
17.
Nakasai
,
K.
, and
Takemura
,
A.
(
1975
). “
Studies on the underwater sound VI: On the underwater calls of fresh dolphins in South America
,”
Bull. Fac. Fish. Nagasaki. Univ.
40
,
7
13
.
18.
Norris
,
K. S.
,
Harvey
,
G. W.
,
Burzell
,
L. A.
, and
Kartha
,
T. D. K.
(
1972
). “
Sound production in the freshwater porpoises Sotalia fluviatilis and Inia geoffrensis, in the Rio Negro, Brazil
,”
Investig. Cetacea
4
,
251
260
.
19.
Podos
,
J.
,
da Silva
,
V. M. F.
, and
Rossi-Santos
,
M. R.
(
2002
). “
Vocalizations of Amazon river dolphins, Inia geoffrensis: insights into the Evolutionary origins of delphinid whistles
,”
Ethology
108
,
601
612
.
20.
Popper, A. N. (1980). “Sound emission and detection by delphinids,” in Cetacean Behaviour: Mechanisms and Functions, edited by L. M. Herman (Wiley, New York), pp. 1–52.
21.
Rendell
,
L. E.
,
Matthews
,
J. N.
,
Gill
,
A.
,
Gordon
,
J. C. D.
, and
MacDonald
,
D. W.
(
1999
). “
Quantitative analysis of tonal calls from five odontocete species, examining interspecific and intraspecific variation
,”
J. Zool.
249
,
403
410
.
22.
Richardson, W. J., Greene, C. R. J., Malme, C. I., and Thomsom, D. H. (1998). Marine Mammals and Noise (Academic, New York).
23.
Sauerland
,
M.
, and
Dehnhardt
,
G.
(
1998
). “
Underwater audiogram of a tucuxi (Sotalia fluviatilis guianensis)
,”
J. Acoust. Soc. Am.
103
,
1199
1204
.
24.
Steiner
,
W. W.
(
1981
). “
Species-specific differences in pure tonal whistle vocalizations of five western North Atlantic dolphin species
,”
Behav. Ecol. Sociobiol.
9
,
241
246
.
25.
Tyack, P. L. (1998). “Acoustic Communication under sea,” in Animal Acoustics Communication—Sound Analysis and Research Methods, edited by S. L. Hopp, M. J. Owen, and C. S. Evans (Springer-Verlag, New York), pp. 163–219.
26.
Van Parijs
,
S. M.
,
Parra
,
G. J.
, and
Corkeron
,
P. J.
(
2000
). “
Sounds produced by Australian Irrawaddy dolphins, Orcaella brevirostris
,”
J. Acoust. Soc. Am.
108
,
1938
1940
.
27.
Wang, D., Wursig, B., and Evans, W. E. (1995a). “Comparisons of whistles among seven odontocete species,” in Sensory Systems of Aquatic Mammals, edited by R. A. Kastelien, J. A. Thomas, and P. E. Nachtigal (De Spil, Woerden, The Netherlands), pp. 299–323.
28.
Wang
,
D.
,
Wursig
,
B.
, and
Evans
,
W. E.
(
1995b
). “
Whistles of bottlenose dolphins: comparisons among populations
,”
Aquat. Mamm.
21
,
65
77
.
29.
Wang
,
D.
,
Wursig
,
B.
, and
Leatherwwod
,
S.
(
2001
). “
Whistles of boto, Inia geoffrensis, and tucuxi, Sotalia fluviatilis
,”
J. Acoust. Soc. Am.
109
,
407
414
.
30.
Wiersma
,
H.
(
1982
). “
Investigations on Cetacea sonar IV. A comparation of wave shapes of odontocete sonar signals
,”
Aquat. Mamm.
9
,
57
66
.
31.
Zar, J. H. (1999). Biostatistical Analysis (Prentice–Hall, Englewood Cliffs, NJ).
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