Real-Time Acquisition of Echolocation Signals by Wild Atlantic Spotted Dolphin, Stenella frontalis, Utilizing Hydrophone Arrays with Simultaneous Underwater Video.
Final rept. 1 Nov 95-30 Nov 97,
WILD DOLPHIN PROJECT JUPITER FL
Pagination or Media Count:
A technique using multi-element arrays of hydrophones with underwater video recording was developed as a tool to accurately measure echolocation signals of free-swimming dolphins. Two configurations of hydrophones, including a line array of three hydrophones spaced at 30 cm and a symmetrical star configuration of four hydrophones spaced at 45.7 Cm, were used. The arrays were held by a skin diver while dolphins oriented on the arrays. Video and acoustic signals were cabled back to the boat. A real-time analogdigital data acquisition system operating at 500 kHz was used to detect, digitize, and store echolocation signals. Spotted dolphin echolocation signals had bimodal frequency spectra with frequency peaks at 40-60 kHz, and 120-140 kHz. Peak to peak source levels up to 210 dB re 1 uPa were measured. Bandwidth clustered around 40 kHz. This system was productive as a portable field tool for acquiring and measuring, real-time, echolocation signals of free-ranging dolphins.
- Acoustic Detection and Detectors