Offshore Acoustic and Visual Survey
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. The
track line of the entire survey is shown in Figure
1. A summary of our results and findings (as well as
the TOC, and a list of tables and figures) can be read
from the executive summary of the Cruise
Report for our 2005 survey, the report entitled "A
Preliminary Acoustic-Visual Survey of Cetaceans in Deep
Waters around Ni'ihau, Kaua'i, and portions of O'ahu, Hawai'i
from aboard the R/V Dariabar, February 2005." The
full report is available; if you would like a copy, please email
us.
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.
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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.
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These findings were presented by Tom Norris at the December
2005 Society of Marine Mammalogy Biennial Conference in
San Diego, both as a poster presentation and a spoken presentation.
The Cetos Poster 2006 known as Hear Me, See Me: An
Acoustic and Visual Survey of Deep-water Cetaceans.
You can also read a daily account of life on the Dariabar
while we were in Hawaii, written by our Cetos scientist
Mari Smultea, by reading "2005
Dariabar Journal".
Finally, for more on our photo ID findings from 2005 from
both this project and the humpback whale social sound project,
see our "Photo-ID results" page.
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