A program of fieldwork was carried out at
Peregian Beach, Australia in collaboration with the University
of Queensland (UQ). This was a Pilot Study concerned with
the setting to work of a system for passive acoustic and visual
tracking of whales, as well as collecting acoustic and remotely
observed behavioral data to provide the baseline information
of the undisturbed ‘normal’ behavior of the whales
during migration along the east coast of Australia.
Background to HARC
There has been little rigorous study of the effects of ambient
noise on baleen whale behavior and the degree to which these
animals interact with their acoustic environment. Studies
of the impact of anthropogenic noise have been very limited.
While a lot has been studied about baleen whale acoustic repertoire
and some about associated behavior, the functions of their
vocalizations remain unclear and the acoustic interaction
with the environment largely unknown. A much better understanding
is required to effectively model the impact of anthropogenic
noise.
Unanswered questions include how these
animals use vocalizations for communication and maintaining
their behavioral repertoire, and how this may be influenced
by the ambient noise field. The biological significance of
sounds produced by individuals is not well understood and
little is known about the context and perception of acoustic
signals. The effects of anthropogenic sound sources on the
whales via interaction with the natural ambient noise field
are thought to be important, however understanding this requires
an understanding of the whales’ use of sound under ‘normal’
(undisturbed) conditions.
The Humpback Whale
Acoustic Research Collaboration
(HARC) is a collaborative project between researchers at the
Scripps Institution of Oceanography (SIO), the Woods Hole
Oceanographic Institution (WHOI), Australia's Defence Science
and Technology Organization (DSTO), and the University of
Queensland (UQ). This collaborative project will study the
behavior of humpback whales, on the east coast of Australia,
in the presence and absence of anthropogenic sources (from
shipping noise and experimental playback), as well as with
variations in a natural ambient noise field, including surf
and wave-induced noise, along known migratory pathways.
An underlying hypothesis is that the influence
of sounds on the whales’ behavior can be assessed by
detailed observations in the presence and absence of the sound.
However to do so requires an accurate assessment of the noise
field at the whale’s location, an understanding of the
physical oceanographic environment and a means of making detailed
observations of responses. A variety of instrumentation, including
digital-recording animal tags, visual and acoustic tracking,
and propagation modeling of the acoustic surroundings will
be used.
The Australia investigators have an ongoing
research program on humpback whale vocalizations with yearly
records of song data extending back 20 years and acoustic
and visual tracking with behavioral observations in 1996 and
1997. Other workers in east Australian waters have built up
an extensive photo identification catalogues of the stock
of migrating humpback whales, and there have been successful
biopsy projects on the same stock.
The SIO and WHOI components leverage on
the Australian investigators’ planned experiments and
each other to generate a greater understanding of whale response
to noise than could be accomplished by any individual program
alone.