Effects of airgun sounds on bowhead whale calling rates: evidence for two behavioral thresholds.
In proximity to seismic operations, bowhead whales (Balaena mysticetus) decrease their calling rates. Here, we investigate the transition from normal calling behavior to decreased calling and identify two threshold levels of received sound from airgun pulses at which calling behavior changes. Data w...
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2015-01-01
|
| Series: | PLoS ONE |
| Online Access: | https://doi.org/10.1371/journal.pone.0125720 |
| _version_ | 1797352475538227200 |
|---|---|
| author | Susanna B Blackwell Christopher S Nations Trent L McDonald Aaron M Thode Delphine Mathias Katherine H Kim Charles R Greene A Michael Macrander |
| author_facet | Susanna B Blackwell Christopher S Nations Trent L McDonald Aaron M Thode Delphine Mathias Katherine H Kim Charles R Greene A Michael Macrander |
| author_sort | Susanna B Blackwell |
| collection | DOAJ |
| description | In proximity to seismic operations, bowhead whales (Balaena mysticetus) decrease their calling rates. Here, we investigate the transition from normal calling behavior to decreased calling and identify two threshold levels of received sound from airgun pulses at which calling behavior changes. Data were collected in August-October 2007-2010, during the westward autumn migration in the Alaskan Beaufort Sea. Up to 40 directional acoustic recorders (DASARs) were deployed at five sites offshore of the Alaskan North Slope. Using triangulation, whale calls localized within 2 km of each DASAR were identified and tallied every 10 minutes each season, so that the detected call rate could be interpreted as the actual call production rate. Moreover, airgun pulses were identified on each DASAR, analyzed, and a cumulative sound exposure level was computed for each 10-min period each season (CSEL10-min). A Poisson regression model was used to examine the relationship between the received CSEL10-min from airguns and the number of detected bowhead calls. Calling rates increased as soon as airgun pulses were detectable, compared to calling rates in the absence of airgun pulses. After the initial increase, calling rates leveled off at a received CSEL10-min of ~94 dB re 1 μPa2-s (the lower threshold). In contrast, once CSEL10-min exceeded ~127 dB re 1 μPa2-s (the upper threshold), whale calling rates began decreasing, and when CSEL10-min values were above ~160 dB re 1 μPa2-s, the whales were virtually silent. |
| first_indexed | 2024-03-08T13:16:06Z |
| format | Article |
| id | doaj.art-2e7ee71b22e94682b9571f08d91e305c |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-03-08T13:16:06Z |
| publishDate | 2015-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-2e7ee71b22e94682b9571f08d91e305c2024-01-18T06:23:05ZengPublic Library of Science (PLoS)PLoS ONE1932-62032015-01-01106e012572010.1371/journal.pone.0125720Effects of airgun sounds on bowhead whale calling rates: evidence for two behavioral thresholds.Susanna B BlackwellChristopher S NationsTrent L McDonaldAaron M ThodeDelphine MathiasKatherine H KimCharles R GreeneA Michael MacranderIn proximity to seismic operations, bowhead whales (Balaena mysticetus) decrease their calling rates. Here, we investigate the transition from normal calling behavior to decreased calling and identify two threshold levels of received sound from airgun pulses at which calling behavior changes. Data were collected in August-October 2007-2010, during the westward autumn migration in the Alaskan Beaufort Sea. Up to 40 directional acoustic recorders (DASARs) were deployed at five sites offshore of the Alaskan North Slope. Using triangulation, whale calls localized within 2 km of each DASAR were identified and tallied every 10 minutes each season, so that the detected call rate could be interpreted as the actual call production rate. Moreover, airgun pulses were identified on each DASAR, analyzed, and a cumulative sound exposure level was computed for each 10-min period each season (CSEL10-min). A Poisson regression model was used to examine the relationship between the received CSEL10-min from airguns and the number of detected bowhead calls. Calling rates increased as soon as airgun pulses were detectable, compared to calling rates in the absence of airgun pulses. After the initial increase, calling rates leveled off at a received CSEL10-min of ~94 dB re 1 μPa2-s (the lower threshold). In contrast, once CSEL10-min exceeded ~127 dB re 1 μPa2-s (the upper threshold), whale calling rates began decreasing, and when CSEL10-min values were above ~160 dB re 1 μPa2-s, the whales were virtually silent.https://doi.org/10.1371/journal.pone.0125720 |
| spellingShingle | Susanna B Blackwell Christopher S Nations Trent L McDonald Aaron M Thode Delphine Mathias Katherine H Kim Charles R Greene A Michael Macrander Effects of airgun sounds on bowhead whale calling rates: evidence for two behavioral thresholds. PLoS ONE |
| title | Effects of airgun sounds on bowhead whale calling rates: evidence for two behavioral thresholds. |
| title_full | Effects of airgun sounds on bowhead whale calling rates: evidence for two behavioral thresholds. |
| title_fullStr | Effects of airgun sounds on bowhead whale calling rates: evidence for two behavioral thresholds. |
| title_full_unstemmed | Effects of airgun sounds on bowhead whale calling rates: evidence for two behavioral thresholds. |
| title_short | Effects of airgun sounds on bowhead whale calling rates: evidence for two behavioral thresholds. |
| title_sort | effects of airgun sounds on bowhead whale calling rates evidence for two behavioral thresholds |
| url | https://doi.org/10.1371/journal.pone.0125720 |
| work_keys_str_mv | AT susannabblackwell effectsofairgunsoundsonbowheadwhalecallingratesevidencefortwobehavioralthresholds AT christophersnations effectsofairgunsoundsonbowheadwhalecallingratesevidencefortwobehavioralthresholds AT trentlmcdonald effectsofairgunsoundsonbowheadwhalecallingratesevidencefortwobehavioralthresholds AT aaronmthode effectsofairgunsoundsonbowheadwhalecallingratesevidencefortwobehavioralthresholds AT delphinemathias effectsofairgunsoundsonbowheadwhalecallingratesevidencefortwobehavioralthresholds AT katherinehkim effectsofairgunsoundsonbowheadwhalecallingratesevidencefortwobehavioralthresholds AT charlesrgreene effectsofairgunsoundsonbowheadwhalecallingratesevidencefortwobehavioralthresholds AT amichaelmacrander effectsofairgunsoundsonbowheadwhalecallingratesevidencefortwobehavioralthresholds |