Reconstruction of Acoustic Exposure on Orcas in Haro Strait
NAVAL RESEARCH LAB WASHINGTON DC ACOUSTICS DIV
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On 5 May 2003, USS Shoup DDG 86, an Arleigh Burke-class Navy Guided Missile Destroyer, transited from the Naval Station Everett via the Strait of Juan de Fuca and the Haro Strait to the Canadian Forces Maritime Experimental Test Range at Nanoose Bay on the eastern side of Vancouver Island, British Columbia. While underway, a sonar training exercise was executed from 1040 to 1440 local time. During the exercise, unusual behavior was observed in one of the resident pods of orcas, raising the question of the sonars impact on them. Due to two coincidental activities, this question can be addressed in detail. Coinciding with Shoups transit, a marine mammal class from Friday Harbor Labs led by Dr. David Bain was observing a pod of Southern Resident killer whales Orcinus orca J pod. The class shadowed the J pod from their boat, recording its behavior, the GPS location of the boat, and the time of day. Figure 1 shows the tracks of USS Shoup and Dr. Bains boat shadowing the J pod overlaid on the bathymetry. Additionally, acoustic recordings were made on monitoring hydrophones deployed by Dr. Val Veirs of Colorado College for his Orca Vocalization and Localization OVAL project. More than 370 recordings on four hydrophones were made, spanning the time period that Shoup was transmitting for its long-range sonar operations.
- Biological Oceanography
- Acoustic Detection and Detectors