Study Findings
Surveys were conducted in waters off O’ahu, Ni’ihau, and Kauai, as well as in deep-water and offshore in the area to the north of Kaua’i. The latter deep-water portion of the survey was called the “Na Pali-Ni’ihau” survey. Over 745 km of survey effort was conducted, including a total of 586 km of visual observations (over half “on effort”) resulting in 78 groups of 179 individual cetacean sightings. In addition, over 200 acoustic detections of cetacean vocalizations were acquired from humpback whales, minke whales and unidentified dolphins.
During the Na Pali-Ni’ihau survey, we obtained recordings of vocalizations from deep diving odontocetes such as sperm whales and pilot whales. We were also able to monitor calls and songs from baleen 
whales including not only the common humpback whale (which sings long and complex songs), but also the rarely seen (in coastal Hawaiian waters) minke whale, which has a unique call known as the “boing” call.
These boing calls were only recently attributed to this cryptic species in work done by a NMFS scientist who was working with us on the Dariabar (Shannon Rankin; available in Rankin and Barlow 2005). Sounds produced by minke whales are known to peak during February in this area of Hawaii, so investigating these calls was one of the things we were interested in doing for our work. We were very fortunate to not only acoustically detect numerous minke whales, but also to sight one during a one-day excursion into deeper waters near Ni’ihau. This is the first documentation of a minke whale in coastal Hawaiian waters.