PMID- 21877781
OWN - NLM
STAT- MEDLINE
DCOM- 20111220
LR  - 20110831
IS  - 1520-8524 (Electronic)
IS  - 0001-4966 (Linking)
VI  - 130
IP  - 2
DP  - 2011 Aug
TI  - Hearing thresholds of a harbor porpoise (Phocoena phocoena) for helicopter 
      dipping sonar signals (1.43-1.33 kHz) (L).
PG  - 679-82
LID - 10.1121/1.3605541 [doi]
AB  - Helicopter long range active sonar (HELRAS), a "dipping" sonar system used by 
      lowering transducer and receiver arrays into water from helicopters, produces 
      signals within the functional hearing range of many marine animals, including the 
      harbor porpoise. The distance at which the signals can be heard is unknown, and 
      depends, among other factors, on the hearing sensitivity of the species to these 
      particular signals. Therefore, the hearing thresholds of a harbor porpoise for 
      HELRAS signals were quantified by means of a psychophysical technique. Detection 
      thresholds were obtained for five 1.25 s simulated HELRAS signals, varying in 
      their harmonic content and amplitude envelopes. The 50% hearing thresholds for 
      the different signals were similar: 76 dB re 1 muPa (broadband sound pressure 
      level, averaged over the signal duration). The detection thresholds were similar 
      to those found in the same porpoise for tonal signals in the 1-2 kHz range 
      measured in a previous study. Harmonic distortion, which occurred in three of the 
      five signals, had little influence on their audibility. The results of this 
      study, combined with information on the source level of the signal, the 
      propagation conditions and ambient noise levels, allow the calculation of 
      accurate estimates of the distances at which porpoises can detect HELRAS signals.
FAU - Kastelein, Ronald A
AU  - Kastelein RA
AD  - Sea Mammal Research Company, Julianalaan 46, Harderwijk, The, Netherlands. 
      researchteam@zonnet.nl
FAU - Hoek, Lean
AU  - Hoek L
FAU - de Jong, Christ A F
AU  - de Jong CA
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Acoust Soc Am
JT  - The Journal of the Acoustical Society of America
JID - 7503051
SB  - IM
MH  - Acoustic Stimulation
MH  - *Acoustics/instrumentation
MH  - *Aircraft
MH  - Animals
MH  - Audiometry
MH  - *Auditory Threshold
MH  - Male
MH  - *Noise
MH  - Phocoena/*physiology
MH  - Psychoacoustics
MH  - *Signal Detection, Psychological
MH  - Sound Spectrography
MH  - Time Factors
MH  - Transducers
EDAT- 2011/09/01 06:00
MHDA- 2011/12/21 06:00
CRDT- 2011/09/01 06:00
PHST- 2011/09/01 06:00 [entrez]
PHST- 2011/09/01 06:00 [pubmed]
PHST- 2011/12/21 06:00 [medline]
AID - 10.1121/1.3605541 [doi]
PST - ppublish
SO  - J Acoust Soc Am. 2011 Aug;130(2):679-82. doi: 10.1121/1.3605541.