Structure of Harbor Porpoise (Phocoena phocoena) Acoustic Signals with High Repetition Rates.:

• Main Authors: Verboom, W.C., Kastelein, R.A.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Chicago,IL, USA: University of Chicago Press 2003
• Subjects: Phocoena phocoena
• Online Access: http://resolver.tudelft.nl/uuid:95adba8f-6362-4f97-ba18-2f00d9068e94

Since July 1993, a systematic study on harbor porpoise (Phocoena phocoena) acoustic signals was conducted in the Netherlands. The first general results were published in Verboom and Kastelein (1995, 1997). Studied were animals kept for veterinary treatment in the Cetacean Rehabilitation Centre at Harderwijk, after being stranded on the Dutch coast. So far, the general conclusion of this acoustic study has been that harbor porpoises produce acoustic signals covering a very broad frequency range (<100 Hz to >160 kHz). These signals fall into three ranges: (1) low frequency (LF), <100 Hz to 10 kHz; (2) midfrequency (MF), 10 kHz to 100 kHz; and (3) high frequency (HF), 100 kHz to > 160 kHz. The various signal ranges probably each have a specific function. Harbor porpoise echolocation clicks have fundamental frequencies of between 1.4 kHz and 2.5 kHz, and above 100 kHz. Porpoises frequently produce social and communicative signals in the LF range up to 2 kHz as well (Verboom pers. obs.). Short duration communicative signals, including sine wave signals, have frequencies of below 10 kHz, most commonly below 2 kHz. Social signals up to 2 kHz can be described as grunts, whoops, and bleats. HF echolocation clicks are similar in frequency spectrum and waveform; LF signals are more variable. Busnel and Dziedzic (1967) showed that the click repetition rate in harbor porpoise signals depends on the distance between the animal's head and the ensonified object. High-repetition-rate trains are used when the observation distance is only a few centimeters.