COI Funded Project: Demonstrating a New Tool to Study Coastal Marine Mammals: Source Levels, Directionality, and Signature Information in Killer Whale Calls


Project Duration: 6/1/99-12/31/00
Key Words: marine mammals, underwater acoustics, Orca communication, noise pollution

Proposed Research

WHOI has a legacy of creating technological solutions to the problems faced by underwater acousticians, particularly in the field of cetacean bioacoustics which was started here by Schevill and Lawrence (Science, 1949). One particularly valuable tool created at WHOI by Watkins and Schevill (DSR, 1972) was the 4-hydrophone dispersed array which has made possible many advances in marine bioacoustics. With student support from RCRC, Miller and Tyack (DSR U, 1998) built on this success by developing a short towable beamforming array. With this array a researcher can follow a particular animal, visually observing its position and behavior while monitoring its sound production with the beamforming array. While we have demonstrated that this technique works, we still must demonstrate its utility in answering basic questions for marine mammal bioacoustics. We propose to use the RCRC award to complete field work and write papers on the following topics: 1.) sound source levels and communication ranges of killer whale social calls; 2.) directionality characteristics of killer whale calls and the potential that killer whales cue their orientation to each other using these directionality characteristics; and 3.) individually-distinctive features ("voice") in killer whale calls. The coastal environment inhabited by the killer whales to be studied in this project are increasingly impacted by noise pollution generated by shipping, whale-watching, and other noise sources. Our improved understanding on source levels and directionality of killer whale calls will also critically aid conservation and management decisions in their coastal ecosystem.