FOR RELEASE: Feb. 18, 1997
Contact: Roger Segelken
Office: (607) 255-9736
Internet: [email protected]
Compuserve: Larry Bernard 72650,565
http://www.news.cornell.edu
ITHACA, N.Y. -- When the National Geographic Society's hunt for living
giant squid sends sperm whales with video cameras to the ocean depths this
month off New Zealand's South Island, the "camerawhales" will be tracked by
the Cornell University Bioacoustics Research program.
Distinctive click sounds produced by diving sperm whales will reveal their
whereabouts to an array of hydrophones (underwater microphones) hanging
vertically in the water, using Cornell equipment that pinpoints sound
sources.
"Fortunately, New Zealand sperm whales usually return to the surface at the
same place where their dives began," said marine biologist Kurt Fristrup,
assistant director of the Cornell Bioacoustics Research Program. "We hope
to learn where they go and what they're eating when they dive," he said,
noting that sperm whales can otherwise cover a lot of territory, traveling
at 3-4 knots during their 15-minute dives.
That's where the "crittercams" will come in handy, as the digital video
cameras, attached by temporary cords, attempt to record high noon in the
high seas: the epic battles between sperm whales and one of their favorite
meals, the giant squid (Architeuthis dux). Cameras have never before
pictured a living giant squid in its deep-water habitat. But
squid-inflicted scars and stomach-content analyses suggest that sperm
whales know where to find giant squid, and they may be the best
collaborators a marine biologist could hope for.
The Cornell sound survey actually begins about two weeks before the first
crittercams are attached to the sperm whales' blubber layer by tethers that
dissolve in about two hours and allow the football-sized camera to float to
the surface.
"The first week or two of sound recording will give us baseline data about
the whales, whether they will be affected by the crittercams, and even
whether they will be disturbed by close approaches from boats," Fristrup
said. Monitoring of the sperm whale click sounds by Cornell bioacoustician
Adam Frankel will continue as the camerawhales dive for giant squid and as
Odyssey, a camera-equipped robotic vehicle developed at MIT's AUV
Laboratory, conducts surveys of the deep habitats. Clyde F.E. Roper of the
Smithsonian Institution is the scientific leader of the expedition, and
James Bellingham of MIT leads the Odyssey team.
"There is good evidence that sperm whale clicks are used for echolocation
and for depth-sounding, but they may not work for locating squid," Fristrup
said. "Squid are poor reflectors of sound." The clicks, which occur in a
variety of patterns called click trains, may be better understood by
biologists after the crittercam sessions, he added, noting that rapid
series of clicks are sometimes heard when sperm whales are "socializing"
and rubbing against one another. Having on-the-scene pictures to go with
the sounds may reveal what all the racket is about.
Bioacousticians don't expect to hear much from the giant squid, Fristrup
said. Squid apparently have no hearing organ and perhaps no strategic
reason for producing sound. Precisely where they lurk -- on the ocean
bottom or at lesser depths -- is not even known. "It's like looking for an
eagle's nest in a series of forests stacked hundreds of layer thick," he
said of the mesopelagic zone, which in tropical waters is about 400 to
1,000 meters down.
"But even if we don't find giant squid," Fristrup said, "we will have
gathered a tremendous amount of information about life in the mesopelagic
zone, about community organization and how predator-prey relationships are
sorted out. It's a part of the ocean that is tremendously rich in
biodiversity and biomass. There's a lot going on down there."
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