to Gray Whales: Acoustic Monitoring
By Journey North and Michael H. Smith, Project Coordinator
led by John Hildebrand uses underwater instruments to listen to
sounds made by the
off Southern California, Alaska, Hawaii, and Antarctica. The scientists
use various acoustic recording tools and ship-based visual
techniques to gather data for this study.
Setting Up the Research Project
March 1, 2010, an exciting new phase of the Gray Whales Count project
Whale Acoustic Lab aboard the Channel Islands National Marine
Sanctuary research vessel R/V Shearwater deployed a HARP ((High-Frequency
Acoustic Recording Package). This instrument will be listening
and recording underwater sounds 24/7 for two months in the Santa
Channel about one mile south of Counter Point. The
will capture the flow of the migration, including cow/calf pairs.
Photo: Michael H. Smith
Sounds Are Scientists Recording?
In addition to whale, dolphin and pinniped vocalizations, we will be recording
all the sounds of the Coal Oil Point ("Counter Point") environment.
It includes noise from vessel traffic passing over and around the migration.
And it includes other noise that likely affects the whales’ migration:
oil pumping at Platform Holly 1.7 nautical miles off
our shore to the southwest. The
unnatural oil-platform is a physical obstacle with clanking metal and
regular vessel visits
to off-load workers and supplies. About every three weeks during
our survey we see a huge barge towed to an arrangement of
six buoys only a half mile offshore where the barge is filled with
crude oil in usually just under 24 hours. (We regularly note if whales
pass outside the buoys that frame the filling process, or inside between
the buoys and shore, or through
the buoys. Mothers and calves often travel between the buoys and shore,
and several whales have been tracked
through the buoys. Very few have been noted as going through the buoys
while the huge barge is in place.)
Marine Science Institute and The Institute for Crustal Studies,
University of California, Santa Barbara
also include the strange gurgles of the natural
methane gas and oil that surround Coal Oil Point. these natural
seeps are a strange wonder that contribute chemicals, noise, and bubbles
to the water though which the whales travel. We wonder about the impact.
Perhaps in the
nearshore, whales may be prepared for those unpleasantries, and yet startled
by the natural, sometimes explosive bubbling of the seeps.
Tools Record Underwater Sounds
The main acoustic tools of scientists are called acoustic recording
packages (ARPs). These instruments sit on the sea floor. They
can continuously record underwater sound at rates up to 1 kHz
for durations over
one-year. ARPs were
developed by the Scripps
Whale Acoustic Lab and have
used worldwide for multi-year studies of baleen whale presence.
The lab is also
developing another, more capable,
high-frequency acoustic recording package (HARP), for
recording odonotocetes (toothed whales, such as sperm whales,
beaked whales, orca, dolphins, and others) at frequencies over
or Research Questions
Oil Point Seep Field with this interactive
map. One of
the largest seep fields in the world and the best studied,
seep field is one of the natural wonders of the world. What effects
do you think the seeps might have on whales and their migration
dolphins, and porpoises can send and receive underwater sound
for communication or hunting purposes. Scientists observe and
listen to the sounds of these marine mammals to learn about
their seasonal and geographic (time-space) movements and about
behavior characteristics. How do you think this information
can help humans ensure a safer future for whales? What other
uses might the information serve?