Abstract




Distributions of Sperm Whales along the Continental Slope in the Northwestern and Central Gulf of Mexico as Determined from an Acoustic Survey. (May 1997)

Troy Daniel Sparks, B.S., Indiana University

Co-Chairs of Advisory Committee: Dr. William E. Evans, and Dr. William E. Grant






The traditional method of estimating whale distributions relies heavily on visual sightings along a surface or aerial vessel trackline. Sperm whales are often difficult visual targets because they spend little time at the surface. Since they spend up to 80% of their time on deep dives, and vocalize in a predictable manner while diving, their distributions can be estimated qualitatively using acoustic sampling techniques. Acoustic sperm whale distributions were determined via a passive towed array along the continental slope of the northwestern and central Gulf of Mexico. Sperm whale distributions were random with respect to season, time of day, contour index, and Beaufort states. However, their distributions were not random across cruises, bottom depths, or dynamic sea height. On the basis of these findings, acoustic assessment with systematic and repeatable tracks is a useful technique for both short and long term determination of sperm whale distributions. Eventually, remote acoustic and oceanographic information may aid in the management and conservation of sperm whales in the Gulf and elsewhere.



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Revised: 03/29/04
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