Determining Source Levels Sound Fields and Body Sizes of Singing Humpback Whales (Megaptera novaeangliae) in the Hawaiian Winter Ground
Abstract
The stereotypical stationary posture adopted by male humpback whales producing song suggests they are attempting to optimize transmission range. Over 23 days between Jan. 28 and Apr. 2 2003, we measured the sound fields of singers using divers equipped with rebreather scuba. A custom-designed "Aquahead" system reliably located singers to within 50 m. Fifty seven singers were located using the Aquahead from distances as far away as 6.1 km in as short a time as 3 min. Divers recorded song using digital video cameras while simultaneously measuring depth and range to a singer's head using hand held ultrasonic range finders. Whale body lengths were obtained using videogrammetry. Source levels were measured up to 203 db re 1 micro Pa 1m. Up to a 16dB difference between frontal and lateral intensities (2.2 kHz) was found indicating that song was most intense at locations directly in front of the singer's rostrum. Body lengths were obtained for 18 singers. Sizes ranged from 10.64 to 13.55 m. A larger dataset is required to compare source levels and sound fields of particular units with whale body size.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2003
- Accession Number
- ADA421803
Entities
People
- Adam A. Pack
- J. Potter
- L. M. Herman
- M. H. Deakos
- M. Hoffmann-kuhnt