Title
Hearing thresholds of harbor seals (Phoca vitulina) for playbacks of seal scarer signals, and effects of the signals on behavior
Author
Kastelein, R.A.
Helder-Hoek, L.
Gransier, R.
Terhune, J.M.
Jennings, N.
de Jong, C.A.F.
Publication year
2015
Abstract
Acoustic mitigation devices (AMDs) are used to deter marine mammals from construction sites to prevent hearing injury by offshore pile-driving noise. In order to quantify the distance at which AMDs designed as ‘seal scarers’ are detected by seals, the 50% hearing thresholds for playbacks of their sounds were determined. The broadband hearing threshold sound pressure levels (SPLs) of two harbor seals for signals from two AMDs were similar (63–69 dB re 1 lPa, rms). Effects of the AMDs on the seals’ behavior were quantified at three SPLs: one which just did not cause behavioral changes, one which caused one of the seals to haul out occasionally, and one which caused one of the seals to haul out more than 10% of the time. The corresponding mean received SPLs were, respectively, Ace Aquatec: 109, 124, and 134 dB re 1 lPa, rms; Lofitech: 128, 133, and 138 dB re 1 lPa, rms. Thus at similar received levels, the Ace Aquatec seems more effective than the Lofitech in deterring harbor seals. Detection and behavioral response distances of the AMD sounds for harbor seals at sea can be estimated by combining the results from the present study with data on AMD source levels, propagation conditions, and background noise levels near construction sites
Subject
Physics & Electronics
AS - Acoustics & Sonar
TS - Technical Sciences
High Tech Maritime and Offshore Systems
Biology
Industrial Innovation
Marine mammals
Acoustics
Behavior
Pile driving
Pinniped
Seal scarer
Offshore wind park
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http://resolver.tudelft.nl/uuid:88a90b8d-675b-4e86-8c9d-74286813254b
DOI
https://doi.org/10.1007/s10750-014-2152-6
TNO identifier
520933
Source
Hydrobiologia, 756 (1), 75-88
Document type
article