The acoustic ecology and behavior of minke whales (Balaenoptera acutorostrata) near tropical and subtropical North Pacific Islands.

Abstract

Passive acoustic monitoring, acoustic localization and acoustic/visual line‐transect surveys of minke whales were conducted near the Hawaiian and Marianas Islands between 2006 and 2010. Acoustic data were collected using (1) towed hydrophone arrays deployed off Kauai and the Marianas Islands, (2) seafloor hydrophones from the U.S. Navy’s Pacific Missile Range Facility (PMRF) northwest of Kauai, (3) the Aloha Cabled Observatory (ACO) seafloor hydrophone northwest of Oahu, and (4) HARP autonomous recorders deployed off the Northwest Hawaiian Island Chain. Significant differences were detected in the pulse repetition rates of boings recorded in Hawaiian versus the Marianas Islands. This information is being used to assess the population characteristics of North Pacific minke whales. Analysis of ACO recordings indicates seasonal patterns, but not diurnal patterns in the number of boings detected. We are in the process of estimating the abundance of vocalizing animals in the main Hawaiian and Northern Marianas Islands study sites using towed hydrophone array data. These results will be compared to estimates made with the PMRF hydrophone data using spatially explicit capture‐recapture methods. Results of these studies are providing a better understanding the acoustic ecology and behavior of minke whales in low‐latitude breeding areas of the North Pacific. [Work supported by ONR.]