ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

4aAB3. Acoustic tracking of whales using hydrophone arrays: Implications for behavioral studies and population estimates.

Christopher W. Clark

Cornell Lab. of Ornithol., Bioacoust. Res. Program, 159 Sapsucker Woods Rd., Ithaca, NY 14850

Understanding how free-ranging whales use sound to communicate, navigate, and find food has been seriously hampered by the inability to consistently identify, locate, and track the animal producing the sound. Only in the most tractable situations (e.g., coastal species, shallow water, breeding/calving season) has it been possible to describe acoustic repertoires and prescribe biological functions. The potential use of such acoustic techniques, in combination with traditional visual observation methods, for population census efforts has been clearly demonstrated in the case of bowhead whales. Recent application of large aperture arrays and beamforming techniques has demonstrated the feasibility of using such systems for locating and tracking vocally active pelagic species. There is every reason to believe that a combination of acoustic tracking and visual observation techniques can be successfully extended for use as a census tool to produce meaningful estimates about relative abundance on blue, finback, and minke whales. Passive acoustic tracking methods, (towed arrays and fixed horizontal arrays) have now been successfully applied to follow individually vocalizing whales for many days, acoustically observe herds of animals, and describe species specific seasonal changes in distribution and relative abundance.