Assessment of Modeled Received Sound Pressure Levels and Movements of Satellite-Tagged Odontocetes Exposed to Mid-Frequency Active Sonar at the Pacific Missile Range Facility: February 2011 Through February 2013
SPACE AND NAVAL WARFARE SYSTEMS CENTER PACIFIC SAN DIEGO CA BIOSCIENCES DIV/ MARINE MAMMAL SCIENTIFIC AND VETERINARY SUPPORT BRANCH
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The Pacific Missile Range Facility PMRF off the island of Kaua i is the site of regular United States U.S. Navy training, some of which involves mid-frequency active sonar MFAS use from different types of military sound sources. PMRF includes acoustic instrumentation which allows for passive acoustic monitoring PAM capabilities to detect and localize sounds such as vocalizing marine mammals. Recent boat-based studies at PMRF have utilized real-time PAM in conjunction with the Marine Mammal Monitoring on Navy Ranges project to detect odontocetes for vectoring a field tagging boat to groups in order to increase the likelihood of deploying satellite tags. The resulting data have allowed for an assessment of habitat use and range of several different species. Some of these boat-based tagging efforts were timed to occur just before Submarine Commanders Courses SCCs occurring on PMRF so that animal movements and diving behavior could be measured both before and during sonar use. PMRF PAM data and tag data were used in this initial analysis to estimate exposure levels for tagged animals and determine whether any large-scale movements of these animals may have occurred in response to MFAS exposure. We first assessed temporal and spatial overlap between the location data from satellite tags and available acoustic recordings and selected a subset of data for which there was sufficient overlap. The MFAS transmission times determined directly using sounds received on the range hydrophones, ship positions at time of transmissions provided by PMRF and animal locations determined from satellite tag positions allowed estimation of the sound pressure levels the tagged animals were exposed to using the U.S. Navy s Personal Computer Interactive Multi-sensor Analysis Tool propagation model.
- Biological Oceanography
- Acoustic Detection and Detectors