Critical ratios (CRs) are useful for estimating detection thresholds of tonal signals when the spectral density of noise is known. In cetaceans, CRs have only been measured for a few animals representing four odontocete species. These data are sparse, particularly for lower frequencies where anthropogenic noise is concentrated. There is currently no systematic method for implementing CR predictions (e.g., a composite frequency-dependent CR function). The current study measures CRs for two bottlenose dolphins (Tursiops truncatus) and estimates composite CR functions. The composite models can aid in predicting and extrapolating auditory masking for a broad range of frequencies.

1.
Au
,
W. W. L.
, and
Moore
,
P. W. B.
(
1990
). “
Critical ratio and critical bandwidth for the Atlantic bottlenose dolphin
,”
J. Acoust. Soc. Am.
88
,
1635
1638
.
2.
Branstetter
,
B. K.
, and
Finneran
,
J. J.
(
2008
). “
Comodulation masking release in bottlenose dolphins (Tursiops truncatus)
,”
J. Acoust. Soc. Am.
124
,
625
633
.
3.
Branstetter
,
B. K.
,
St. Leger
,
J.
,
Acton
,
D.
,
Stewart
,
J.
,
Houser
,
D. H.
,
Finneran
,
J. J.
, and
Jenkins
,
K.
(
2017
). “
Killer whale (Orcinus orca) behavioral audiograms
,”
J. Acoust. Soc. Am.
141
,
2387
2398
.
4.
Branstetter
,
B. K.
,
Trickey
,
J. S.
,
Bahktiari
,
K.
,
Black
,
A.
,
Aihara
,
H.
, and
Finneran
,
J. J.
(
2013
). “
Auditory masking patterns in bottlenose dolphins (Tursiops truncatus) with natural, anthropogenic, and controlled noise
,”
J. Acoust. Soc. Am.
133
,
1811
1818
.
5.
Erbe
,
C.
,
Reichmuth
,
C.
,
Cunningham
,
K. A.
,
Lucke
,
K.
, and
Dooling
,
R.
(
2016
). “
Communication masking in marine mammals: A review and research strategy
,”
Mar. Pollut. Bull.
103
,
15
38
.
6.
Finneran
,
J. J.
(
2003
).
An Integrated Computer-Controlled System for Marine Mammal Auditory Testing
(
SSC San Diego
,
San Diego, CA
).
7.
Finneran
,
J. J.
(
2016
).
Auditory Weighting Functions and TTS/PTS Exposure Functions for Marine Mammals Exposed to Underwater Noise, SSC Pacific TR 3026
(
SSC Pacific
,
San Diego, CA
).
8.
Finneran
,
J. J.
,
Schlundt
,
C. E.
,
Carder
,
D. A.
, and
Ridgway
,
S. H.
(
2002
). “
Auditory filter shapes for the bottlenose dolphin (Tursiops truncatus) and the white whale (Delphinapterus leucas) derived with notched noise
,”
J. Acoust. Soc. Am.
112
,
322
328
.
9.
Fletcher
,
H.
(
1940
). “
Auditory patterns
,”
Rev. Mod. Phys.
12
,
47
65
.
10.
Houser
,
D. S.
, and
Finneran
,
J. J.
(
2006
). “
Variation in the hearing sensitivity of a dolphin population obtained through the use of evoked potential audiometry
,”
J. Acoust. Soc. Am.
120
,
4090
4099
.
11.
Johnson
,
C. S.
(
1968
). “
Masked tonal thresholds in the bottlenosed porpoise
,”
J. Acoust. Soc. Am.
44
,
965
967
.
12.
Johnson
,
C. S.
,
McManus
,
M. W.
, and
Skaar
,
D.
(
1989
). “
Masked tonal hearing thresholds in the beluga whale
,”
J. Acoust. Soc. Am.
85
,
2651
2654
.
13.
Kastelein
,
R. A.
,
Wensveen
,
P. J.
,
Hoek
,
L.
,
Au
,
W. W. L.
,
Terhune
,
J. M.
, and
de Jong
,
C. A. F.
(
2009
). “
Critical ratios in harbor porpoises (Phocoena phocoena) for tonal signals between 0.315 and 150 kHz in random Gaussian white noise
,”
J. Acoust. Soc. Am.
126
,
1588
1597
.
14.
Lemonds
,
D. W.
,
Kloepper
,
L.
,
Nachtigall
,
P. E.
,
Au
,
W. W. L.
,
Vlachos
,
S.
, and
Branstetter
,
B. K.
(
2011
). “
A re-evaluation of auditory filter shape in delphinid odontocetes: Evidence of constant-bandwidth filters
,”
J. Acoust. Soc. Am.
135
,
3107
3114
.
15.
Levitt
,
H.
(
1971
). “
Transformed up-down methods in psyhcoacoustics
,”
J. Acoust. Soc. Am.
49
,
467
477
.
16.
Patterson
,
R. D.
, and
Moore
,
B. C. J.
(
1986
). “
Auditory filters and excitation patterns as representations of frequency resolution
,” in
Frequency Selectivity in Hearing
, edited by
B. C. J.
Moore
(
Academic
,
London
), pp.
123
127
.
17.
Sills
,
J. M.
,
Southall
,
B.
, and
Reichmuth
,
C.
(
2017
). “
The influence of temporally varying noise from seismic air guns on the detection of underwater sounds by seals
,”
J. Acoust. Soc. Am.
141
,
996
1008
.
18.
Thomas
,
J. A.
,
Pawloski
,
J. L.
, and
Au
,
W. W. L.
(
1990
). “
Masked hearing abilities in a False Killer Whale (Pseudorca crassidens)
,” in
Sensory Abilities of Cetaceans: Laboratory and Field Evidence
, edited by
J. A.
Thomas
and
R. A.
Kastelein
(
Plenum
,
New York
, ), pp.
395
-
404
.
19.
Trickey
,
J. S.
,
Branstetter
,
B. K.
, and
Finneran
,
J. J.
(
2010
). “
Auditory masking of a 10 kHz tone with environmental, comodulated, and Gaussian noise in bottlenose dolphins (Tursiops truncatus)
,”
J. Acoust. Soc. Am.
128
,
3799
3804
.
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