Acoustic ecology and behavior of minke whales in the Hawaiian and Marianas islands: localization, abundance estimation, and characterization of minke whale "boings".

Balaenoptera acutorostrata (minke whale) is a small and elusive baleen whale that is rarely sighted in the tropical waters of the North Pacific Ocean. During winter and spring, complex sounds called ”boings” are frequently detected around the Hawaiian Islands and other Pacific island regions (Norris et al. 2009 ; Thompson and Friedl 1982 ) . Although boings were described over 45 years ago (Wenz 1964 ) , they were not attributed to minke whales until very recently (Rankin and Barlow 2005 ) . Sightings of Balaenoptera acutorostrata are uncommon in tropical and subtropical waters; however, boings are frequently detected around the Hawaiian Islands using seafloor hydrophones and from hydrophone arrays towed from research vessels. Even today, very little is known about acoustic behaviors and ecology of Balaenoptera acutorostrata. The long-term objective of this research effort is to improve our understanding of the acoustic ecology and behavior of Balaenoptera acutorostrata in their breeding habitat. A primary goal of this study is to compare characteristics of boings recorded in the Hawaiian Islands (central North Pacific) to other regions in the central and western North Pacific (e.g., the Northern Mariana Islands). These results will be used to elucidate stock identities and population characteristics for Balaenoptera acutorostrata in the Pacific Islands. Another goal is to estimate the local abundance of calling Balaenoptera acutorostrata for our main study sites off the Hawaiian Island of Kaua’i and around the Marianas Islands. Finally, we are collecting information Acoustic Ecology and Behavior of Minke Whales in the Hawaiian and Marianas Islands: Localization, Abundance Estimation, and Characterization of Minke Whale “Boings”