Recordings of manatee (Trichechus manatus spp.) vocalizations were made in Florida and Belize to quantify both intraspecific and geographic variation. Manatee vocalizations were relatively stereotypical in that they were short tonal harmonic complexes with small frequency modulations at the beginning and end. Vocalizations ranged from almost pure tones to broader-band tones that had a raspy quality. The loudest frequency was typically the second or third harmonic, with average received levels of the peak frequency of about 100 dB re 1 μPa. Signal parameters measured from these calls showed the manatees from Belize and Florida have overlapping distributions of sound duration, peak frequency, harmonic spacing, and signal intensity, indicating no obvious distinguishing characteristics between these isolated populations.

1.
Bengtson
,
J. L.
, and
Fitzgerald
,
S. M.
(
1985
). “
Potential role of vocalizations in West Indian manatees
,”
J. Mammal.
66
(
4
),
816
819
.
2.
Evans
,
W. E.
, and
Herald
,
E. S.
(
1970
). “
Underwater calls of a captive Amazon manatee, Trichechus inunguis
,”
J. Mammal.
51
,
820
823
.
3.
Gerstein
,
E. R.
,
Gerstein
,
L.
,
Forsythe
,
S. E.
, and
Blue
,
J. E.
(
1999
). “
The underwater audiogram of the West Indian manatee (Trichechus manatus)
,”
J. Acoust. Soc. Am.
105
,
3575
3583
.
4.
Johnson
,
M. P.
, and
Tyack
,
P. L.
(
2003
). “
A digital acoustic recording tag for measuring the response of wild marine mammals to sound
,”
IEEE J. Ocean. Eng.
28
(
1
),
3
12
.
5.
Ketten, D. R., Odell, D. K., and Domning, D. P. (1992). Marine Mammal Sensory Systems, edited by J. Thomas (Plenum, New York), pp. 77–95.
6.
Nowacek, S. M., Wells, R. S., Nowacek, D. P., Owen, E. C. G., Speakman, T. R., and Flamm, R. O. (2000). “Manatee behavioral responses to vessel approaches,” Report No. FWC-00127, 2000.
7.
Rogers, P. H., and Cox, M. (1988). Sensory Biology of Aquatic Animals, edited by J. Atema, A. N. Popper, and R. R. Fay (Springer-Verlag, New York).
8.
Schevill
,
W. E.
, and
Watkins
,
W. A.
(
1965
). “
Underwater calls of Trichechus (Manatee)
,”
Nature (London)
205
(
4969
),
373
374
.
9.
Sonoda, S., and Takemura, A. (1973). “Underwater sounds of the manatees, Trichechus manatus and T. inunguis (Trichechidae),” Report of the Institute for Breeding Research, Tokyo University of Agriculture, Vol. 4, pp. 19–24.
10.
Sousa-Lima
,
R. S.
,
Paglia
,
A. P.
, and
Da Fonseca
,
G. A. B.
(
2002
). “
Signature information and individual recognition in the isolation calls of Amazonian manatees, Trichechus inunguis (Mammalia: Sirenia)
,”
Anim. Behav.
63
,
301
310
.
11.
U. S. Marine Mammal Commission (2002). “Annual Report of the U.S. Marine Mammal Commission,” U.S. Marine Mammal Commission, 4340 East West Highway, Suite 905, Bethesda, MD.
12.
Weigle, B. L., Wright, I. E., and Huff, J. A. (1994). “Responses of manatees to an approaching boat: a pilot study,” presented at the First international manatee and dugong research conference, Gainesville, FL.
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