Simulated seal scarer sounds scare porpoises, but not seals: species-specific responses to 12 kHz deterrence sounds
Acoustic harassment devices (AHD) or ‘seal scarers’ are used extensively, not only to deter seals from fisheries, but also as mitigation tools to deter marine mammals from potentially harmful sound sources, such as offshore pile driving. To test the effectiveness of AHDs, we conducted two studies wi...
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doaj-ba1fdcd279db4534b0b15c721d941b2b2020-11-25T04:10:32ZengThe Royal SocietyRoyal Society Open Science2054-57032017-01-014710.1098/rsos.170286170286Simulated seal scarer sounds scare porpoises, but not seals: species-specific responses to 12 kHz deterrence soundsLonnie MikkelsenLine HermannsenKristian BeedholmPeter Teglberg MadsenJakob TougaardAcoustic harassment devices (AHD) or ‘seal scarers’ are used extensively, not only to deter seals from fisheries, but also as mitigation tools to deter marine mammals from potentially harmful sound sources, such as offshore pile driving. To test the effectiveness of AHDs, we conducted two studies with similar experimental set-ups on two key species: harbour porpoises and harbour seals. We exposed animals to 500 ms tone bursts at 12 kHz simulating that of an AHD (Lofitech), but with reduced output levels (source peak-to-peak level of 165 dB re 1 µPa). Animals were localized with a theodolite before, during and after sound exposures. In total, 12 sound exposures were conducted to porpoises and 13 exposures to seals. Porpoises were found to exhibit avoidance reactions out to ranges of 525 m from the sound source. Contrary to this, seal observations increased during sound exposure within 100 m of the loudspeaker. We thereby demonstrate that porpoises and seals respond very differently to AHD sounds. This has important implications for application of AHDs in multi-species habitats, as sound levels required to deter less sensitive species (seals) can lead to excessive and unwanted large deterrence ranges on more sensitive species (porpoises).https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.170286acoustic harassment devicesseal scarerharbour porpoiseharbour sealmitigationpile driving |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Lonnie Mikkelsen Line Hermannsen Kristian Beedholm Peter Teglberg Madsen Jakob Tougaard |
spellingShingle |
Lonnie Mikkelsen Line Hermannsen Kristian Beedholm Peter Teglberg Madsen Jakob Tougaard Simulated seal scarer sounds scare porpoises, but not seals: species-specific responses to 12 kHz deterrence sounds Royal Society Open Science acoustic harassment devices seal scarer harbour porpoise harbour seal mitigation pile driving |
author_facet |
Lonnie Mikkelsen Line Hermannsen Kristian Beedholm Peter Teglberg Madsen Jakob Tougaard |
author_sort |
Lonnie Mikkelsen |
title |
Simulated seal scarer sounds scare porpoises, but not seals: species-specific responses to 12 kHz deterrence sounds |
title_short |
Simulated seal scarer sounds scare porpoises, but not seals: species-specific responses to 12 kHz deterrence sounds |
title_full |
Simulated seal scarer sounds scare porpoises, but not seals: species-specific responses to 12 kHz deterrence sounds |
title_fullStr |
Simulated seal scarer sounds scare porpoises, but not seals: species-specific responses to 12 kHz deterrence sounds |
title_full_unstemmed |
Simulated seal scarer sounds scare porpoises, but not seals: species-specific responses to 12 kHz deterrence sounds |
title_sort |
simulated seal scarer sounds scare porpoises, but not seals: species-specific responses to 12 khz deterrence sounds |
publisher |
The Royal Society |
series |
Royal Society Open Science |
issn |
2054-5703 |
publishDate |
2017-01-01 |
description |
Acoustic harassment devices (AHD) or ‘seal scarers’ are used extensively, not only to deter seals from fisheries, but also as mitigation tools to deter marine mammals from potentially harmful sound sources, such as offshore pile driving. To test the effectiveness of AHDs, we conducted two studies with similar experimental set-ups on two key species: harbour porpoises and harbour seals. We exposed animals to 500 ms tone bursts at 12 kHz simulating that of an AHD (Lofitech), but with reduced output levels (source peak-to-peak level of 165 dB re 1 µPa). Animals were localized with a theodolite before, during and after sound exposures. In total, 12 sound exposures were conducted to porpoises and 13 exposures to seals. Porpoises were found to exhibit avoidance reactions out to ranges of 525 m from the sound source. Contrary to this, seal observations increased during sound exposure within 100 m of the loudspeaker. We thereby demonstrate that porpoises and seals respond very differently to AHD sounds. This has important implications for application of AHDs in multi-species habitats, as sound levels required to deter less sensitive species (seals) can lead to excessive and unwanted large deterrence ranges on more sensitive species (porpoises). |
topic |
acoustic harassment devices seal scarer harbour porpoise harbour seal mitigation pile driving |
url |
https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.170286 |
work_keys_str_mv |
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