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Strategies for weighting exposure in the development of acoustic criteria for marine mammals. by the Noise Exposure Criteria Group Presented to the 150th Meeting of the Acoustical Society of America 17–21 October 2005, Minneapolis, MN. Ann Bowles Roger Gentry William Ellison - PowerPoint PPT Presentation
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Strategies for weighting Strategies for weighting exposure in the exposure in the
development of acoustic development of acoustic criteria for marine criteria for marine
mammalsmammalsby the by the Noise Exposure Criteria GroupNoise Exposure Criteria Group
Presented to the 150th Meeting of the Acoustical Presented to the 150th Meeting of the Acoustical Society of AmericaSociety of America
17–21 October 2005, Minneapolis, MN 17–21 October 2005, Minneapolis, MN
Noise Exposure Criteria Noise Exposure Criteria GroupGroup (Authors) (Authors)
Ann BowlesAnn Bowles
Roger GentryRoger Gentry
William EllisonWilliam Ellison
James FinneranJames Finneran
Charles GreeneCharles Greene
David KastakDavid Kastak
Darlene KettenDarlene Ketten
James MillerPaul NachtigallW. John RichardsonBrandon Southall*Jeanette ThomasPeter Tyack
Former ContributorsWhitlow AuSam Ridgway* (ret)Ron Schusterman (ret)
*Note that Brandon Southall was left off the author list in the program. An erratum willbe published in the Journal and author list will be corrected online.
NMFS Charge to the NMFS Charge to the Noise Exposure Criteria Noise Exposure Criteria
GroupGroupDevelop science-based criteria for the onset of auditory injury and behavioral disruption from
noise exposure.
•It became clear that we needed to emphasize some frequencies and deemphasize others
•It would be best if each species had their own weighting functions for injury and behavior.
•But we don’t have the data to support the specification of these weighting functions.
•While these data are being collected, we need interim weighting functions.
20
40
60
80
100
120
140
160
10 100 1000 10000 100000 1000000
Frequency (Hz)
dB (r
e: 1
uPa)
Low-freq. Cetacean (estimated)Pinniped (air)Pinniped (water)Mid-freq. CetaceanHigh-freq. Cetacean
Marine Mammal GroupsMarine Mammal Groups: Taxa were : Taxa were categorized into groups by hearing categorized into groups by hearing
functionfunction
Composite data (see: Richardson Composite data (see: Richardson et alet al., 1995; Kastelein ., 1995; Kastelein et alet al., 2002) ., 2002)
Human Hearing: Weighting Human Hearing: Weighting FunctionsFunctions
10 100 1000 10000
Frequency (Hz)
0
20
40
60
80
100
120
140
Le
ve
l (dB
re 2
0 u
Pa
)
Human(M AF)
C-w eighting(inverted)
A-weighting(inverted)
Nominal Range of Human Hearing20 Hz – 20 kHz
(source: Harris 1998) (source: Harris 1998)
• In humans, an idealized version of the 40-phon equal loudness function (A-weighting) and 100-phon equal loudness function (C-weighting) are used to filter sound when calculating estimates of exposure.
Leatherwood, J.D., B.M. Sullivan, K.P. Shepherd, D.A. McCurdy, and S.A. Brown. 2002. Summary of recent NASA
studies of human response to sonic boom. Journal of the Acoustical Society of America 111(1, pt. 2): 566–598.
Frequency weighting improves Frequency weighting improves correlation between noise exposure correlation between noise exposure
and human responseand human response
Log
measu
re o
f an
noya
nce
Example of sound exposure Example of sound exposure relative to human hearing and relative to human hearing and
frequency weightingfrequency weighting
10 100 1,000
Frequency (Hz)
0
20
40
60
80
100
120
140
So
un
d P
res
su
re L
ev
el (d
B)
Human (M AF)
C-w eighting(Inverted)
Spectrumof Sonic Boom
(arb. dB)
A-weighting (inverted)
• A- and C-weighting admit different portions of the sonic boom spectrum (in arb. dB).• These weighting functions admit more low frequency noise than the human auditory threshold function.
Example of noise exposure* Example of noise exposure* relative to marine mammal relative to marine mammal
hearinghearing
Pinniped threshold data from: Kastak, D. and R.J. Schusterman. 1998. Low-frequency amphibious hearing in pinnipeds: methods, measurements, noise and ecology. Journal of the
Acoustical Society of America 103(4): 2216 – 2228.
Frequency (Hz)
dB (re 20uP
a)
1 10 100 10000
20
40
60
80
100
120
140
California Sea Lion
Frequency (Hz)
dB (re 20uP
a)
1 10 100 10000
20
40
60
80
100
120
140
Harbor Seal
Frequency (Hz)
dB (re 20uP
a)
1 10 100 10000
20
40
60
80
100
120
140
Northern Elephant Seal
*Sonic boom spectrum (arb. dB)
Human Frequency Weighting Human Frequency Weighting NetworksNetworks
101
102
103
104
-60
-50
-40
-30
-20
-10
0
A and C weighting
frequency (Hz)
wei
ghtin
g (d
B)
C-Weighting
A-weighting
2)9.737()5.107)(12200)(6.20(
12200log20)(
5.0225.0222222
42
10
ffff
ffA
06.0)12200)(6.20(
12200log20)(
2222
22
10
ff
ffC
H. Singleton, “Frequency Weighting Equations,” H. Singleton, “Frequency Weighting Equations,” http://www.cross-spectrum.com/audio/weighting.html, (2004)., (2004).
Weighting Functions for Weighting Functions for Animals Animals
• Weightings should improve exposure estimates • i.e., reduce the variability of correlations between dose and response
• Ad hoc weightings have been used historically• Human A- and C-weightings (whether or not they match the animals’ hearing range)
• Species-typical auditory threshold functions ( “O-weighting” for owls [Delaney et al. 1999], “R-weighting” for laboratory rats [NIH]).
• “Flat” weighting
o Rectangular weighting constrained by the upper and lower boundaries of the measurement system.
• Rectangular weighting constrained by the upper and low boundaries of the animal’s hearing range.
• The 1/3-octave band with the greatest energy
Threshold WeightingThreshold Weighting
The absolute auditory threshold The absolute auditory threshold function (audiogram) has been function (audiogram) has been suggested as a surrogate weighting suggested as a surrogate weighting function for marine species exposed to function for marine species exposed to underwater sound (Malme 1990; underwater sound (Malme 1990; Heathershaw et al. 2001; Nedwell and Heathershaw et al. 2001; Nedwell and Edwards, 2002; Nedwell et al, 2005) as Edwards, 2002; Nedwell et al, 2005) as well as terrestrial animals (Delaney et well as terrestrial animals (Delaney et al. 1999; Bjork et al. 2000) al. 1999; Bjork et al. 2000)
The utility of this approach has not been The utility of this approach has not been tested empirically. tested empirically.
Weighting Functions for Weighting Functions for Marine Mammals Marine Mammals
• S3 WG90 is developing recommendations for marine mammal weighting functions, but adequate science is needed to produce standardized, taxon-specific weightings
• In the interim, a simple, conservative weighting scheme was developed for marine mammals
M-WeightingM-Weighting
))((log20)(
2222
22
10highlow
high
ffff
fffM
Species GroupSpecies Group fflowlow ffhighhigh
Low-frequency cetaceans
7 Hz7 Hz 22 kHz22 kHz
Mid-frequency Mid-frequency cetaceans cetaceans
150 Hz150 Hz 160 kHz160 kHz
High-frequency High-frequency cetaceans cetaceans
200 Hz200 Hz 180 kHz180 kHz
Pinnipeds in Pinnipeds in water water
75 Hz75 Hz 75 kHz75 kHz
Pinnipeds in airPinnipeds in air 75 Hz75 Hz 30 kHz30 kHz
The frequency cutoffs can be obtained from anatomical studies. The numbers here are
conservative estimate of the upper and lower boundaries for the most sensitive members of each group.
Functional Hearing Group
EstimatedAuditory
Bandwidth
Genera Represented(# species/sub-spec.)
Frequency Weighting Network
Low-frequency cetaceans
7 Hzto
22 kHz
Balaena, Caperea, Eschrichtius, Megaptera, Balaenoptera
(13 species/sub-spec.)
Mlf (lf: low-frequency
cetacean)
Mid-frequency cetaceans
150 Hzto
160 kHz
Steno, Sousa, Sotalia, Tursiops, Stenella, Delphinus, Lagenodelphis,
Lagenorhynchus, Lissodelphis, Grampus, Peponocephala, Feresa, Pseudorca, Orcinus, Globicephala,
Orcacella, Physeter, Kogia, Delphinapterus, Monodon, Ziphius,
Berardius, Tasmacetus, Hyperoodon, Mesoplodon
(56 species/sub-spec.)
Mmf (mf: mid-frequency
cetaceans)
High-frequency cetaceans
200 Hzto
180 kHz
Phocoena, Neophocaena, Phocoenoides, Platanista, Inia,
Lipotes, Pontoporia, Cephalorhynchus
(18 species/sub-spec.)
Mhf (hf: high-frequency
cetaceans)
Pinnipedsin water
75 Hzto
75 kHz
Arctocephalus, Callorhinus, Zalophus, Eumetopias, Neophoca, Phocarctos, Otaria, Erignathus,
Phoca, Pusa, Halichoerus, Histriophoca, Pagophilus,
Cystophora, Monachus, Mirounga, Leptonychotes, Ommatophoca,
Lobodon, Hydrurga, and Odobenus(41 species/sub-spec.)
Mpw (pw: pinnipeds in
water)
Pinnipeds in air
75 Hzto
30 kHz
Same genera as pinnipeds in water(41 species/sub-spec.)
Mpa (pa: pinnipeds in
air)
These groups are relatively heterogeneous – it was the breakdown that is supported with available data.
““M-weighting” for cetacean M-weighting” for cetacean hearinghearing
10 100 1,000 10,000 100,000
Frequency (Hz)
-20
-15
-10
-5
0
5
Re
lativ
e L
ev
el (d
B)
HumanC-w eighting
M ysticete
M id-FrequencyO dontocete
H i-FrequencyO dontocete
Low-frequency cetaceans - flow: 7 Hz, fhigh: 22 kHz
Mid-frequency cetaceans - flow: 150 Hz, fhigh: 160 kHz
High-frequency cetaceans - flow: 200 Hz, fhigh: 180 kHz
The resulting family of weighting functions should yield metrics that are most relevant for high-amplitude noise exposures (where loudness functions are expected to flatten) and are likely conservative.
““M-weighting” for pinniped M-weighting” for pinniped hearinghearing
10 100 1,000 10,000 100,000
Frequency (Hz)
-20
-15
-10
-5
0
5
Re
lativ
e L
ev
el (d
B)
PinnipedIn-Air
P innipedUnderw ater
Human C-w eighting
Note that we are not taking into account the differences in best sensitivity among species.
ConclusionsConclusions The Noise Exposure Criteria Group has developed The Noise Exposure Criteria Group has developed
weighting procedures for exposure metrics that will weighting procedures for exposure metrics that will be used as criteria forbe used as criteria for injury injury behavioral disruptionbehavioral disruption
Noise exposure metrics for humans have proven to Noise exposure metrics for humans have proven to be more effective when they account for be more effective when they account for psychophysical properties of the auditory system, psychophysical properties of the auditory system, particularly loudness perception. particularly loudness perception.
The Group has proposed to weight noise data by The Group has proposed to weight noise data by functions that admit sound throughout the frequency functions that admit sound throughout the frequency range of hearing in five marine mammal groupings. range of hearing in five marine mammal groupings.
This procedure is considered conservativeThis procedure is considered conservative The “precautionary principle” is always used in developing The “precautionary principle” is always used in developing
criteria for species at risk. criteria for species at risk. Empirical data are essential to finding better estimators of Empirical data are essential to finding better estimators of
exposure including refining the cutoff frequencies for the exposure including refining the cutoff frequencies for the weightingsweightings. .
ReferencesReferences Bjork, E., T. Nevalainen, M. Hakumaki, and H.-M. Voipio. (Bjork, E., T. Nevalainen, M. Hakumaki, and H.-M. Voipio. (20002000). R-weighting provides ). R-weighting provides
better estimation for rat hearing sensitivity. Lab. Anim. better estimation for rat hearing sensitivity. Lab. Anim. 3434,136–144. ,136–144. C. M. Harris, C. M. Harris, Handbook of Acoustical Measurements and Noise ControlHandbook of Acoustical Measurements and Noise Control, 3, 3rdrd ed., Acoustical ed., Acoustical
Society of America, 1999.Society of America, 1999. R. A. Kastelein, P. Bunskoek, M. Hagedoorn, W. W. L. Au, and D. de Haan, “Audiogram of R. A. Kastelein, P. Bunskoek, M. Hagedoorn, W. W. L. Au, and D. de Haan, “Audiogram of
a harbor porpoise (a harbor porpoise (Phocoena phocoenaPhocoena phocoena) measured with narrow-band frequency-modulated ) measured with narrow-band frequency-modulated signals,” signals,” J. Acoust. Soc. AmJ. Acoust. Soc. Am., 112(1), 334-344, 2002.., 112(1), 334-344, 2002.
D. Kastak and R.J. Schusterman, Low-frequency amphibious hearing in pinnipeds: methods, measurements, noise and ecology, J. Acoust. Soc. Am., 103(4), 2216 – 2228, 1998.
Heathershaw, A.D., P.D. Ward and A.M. David. 2001. The environmental impact of underwater sound. p. 1-12 In: 2nd Symp. on underwater bio-sonar and bioacoustic systems, Loughborough Univ., July 2001. Proc. Inst. Acoustics 23(4). Inst. of Acoustics, St Albans, Herts, U.K. 202 p.
J. D. Leatherwood, B.M. Sullivan, K.P. Shepherd, D.A. McCurdy, and S.A. Brown, “Summary of recent NASA studies of human response to sonic boom,” J. Acoust. Soc. AmJ. Acoust. Soc. Am., ., 111(1, pt. 2), 566–598, 2002.
J. Nedwell, B. Edwards, 'Measurements of underwater noise in the Arun River during J. Nedwell, B. Edwards, 'Measurements of underwater noise in the Arun River during piling at County Wharf, Littlehampton', Subacoustech Report Reference: 513R0108, piling at County Wharf, Littlehampton', Subacoustech Report Reference: 513R0108, http://www.subacoustech.com/downloads/513R0108.pdfhttp://www.subacoustech.com/downloads/513R0108.pdf, August 2002., August 2002.
J. Nedwell, J. Lovell, A. Turnpenny, “Experimental validation of a species-specific J. Nedwell, J. Lovell, A. Turnpenny, “Experimental validation of a species-specific behavioral impact metric for underwater noise,” J. Acoust. Soc. Am., 118(3), 2005.behavioral impact metric for underwater noise,” J. Acoust. Soc. Am., 118(3), 2005.
W. J. Richardson, Jr., C. R. Greene, C. I. Malme, D. H. Thomson, W. J. Richardson, Jr., C. R. Greene, C. I. Malme, D. H. Thomson, Marine Mammals and Marine Mammals and NoiseNoise, Academic Press, 1995., Academic Press, 1995.
H. Singleton, “Frequency Weighting Equations,” H. Singleton, “Frequency Weighting Equations,” http://www.cross-spectrum.com/audio/weighting.htmlhttp://www.cross-spectrum.com/audio/weighting.html, (2004)., (2004).