An inexpensive, portable, and rugged system for recording the low-frequency sounds of cetaceans
Many studies have been done on the low-frequency sounds of cetaceans. However, few of these studies have involved coincident photoidentification, biopsy, and behavioral observation. In order to make acoustical recordings in conjunction with the regular visual fieldwork done from inflatable boats on the baleen whales of the St. Lawrence, a recording system was designed to meet several requirements. It had to be very inexpensive; light enough to be carried onto the boat each day and deployed by hand; and rugged enough to survive being pounded and soaked when stored on the open boat. The resulting system consisted of two main parts: a recording system made up of DAT recorder, amplifiers, filters, batteries and voltage regulators; and a surfacemotion isolation system made up of a spar buoy, omnidirectional hydrophone, cable and damping plate. A mixing circuit allowed for real-time detection of infrasonic signals through a pair of headphones. In addition to the description of the system and its calibration, samples of blue, fin, minke and humpback whale recordings will be presented, and a brief comparison of the system with and without the spar buoy will be shown. [Work supported by a graduate fellowship from NSF.]
Berchok, C.L., Gabrielson, T.B., and Bradley, D.L. 1999. An inexpensive, portable, and rugged system for recording the low-frequency sounds of cetaceans. J. Acoust. Soc. Am. 106:2281. Oral Presentation.