An onboard acoustic data logger to record biosonar of free-ranging bottlenose dolphins

Publisher Website
Google Scholar
Abstract
An acoustic data logger has been developed which utilizes a two-channel DAT recorder housed in aluminum and attached to the dorsal fin. The recorder has a flat frequency response from 10 Hz to 14 kHz, and each tape can store 120 min. The first suction-cup hydrophone (sensitivity −205 dB) was placed 10 cm posterior of the blowhole, and the second 20 cm below the lateral base of the dorsal fin. The anterior ‘‘high-frequency’’ hydrophone, designed to record echolocation signals, has unity gain and a one-pole 10-kHz high-pass filter. The ‘‘ambient’’ hydrophone located at the base of the dorsal fin has +18-dB gain and a one-pole 1-kHz high-pass filter. To obtain echolocation recordings the ‘‘high-frequency’’ hydrophone was filtered through a simple demodulator in one of the deployments. The package includes VHF radio transmitters for tracking the animal and recovering the package after it releases via corrosible magnesium links. The package was attached to temporarily restrained animals which, after release, were followed to record behavioral data while the recorder logged acoustic activity. During the two successful deployments to date the logger recorded animal vocalizations, surfacing events, the sounds of passing boats, and hydrodynamic sounds produced by the animal’s fluke strokes. [Work supported by ONR, OVF, SeaGrant-WHOI.]
Keywords

This publication has 0 references indexed in Scilit: