To record and study the whales' vocalizations, the researchers used an array of hydrophones suspended in the water and marked with brightly colored floats so that observers in the water and on the boat could note the locations of whales relative to the hydrophones. Observers also took time-stamped underwater video of the whales for later comparison with the audio recordings. During three seasons in the field, from 1997 to 1999, Gedamke recorded 92 hours of whale sounds during 49 encounters.
Because the star-wars vocalization is so unique, researchers can now use it to learn more about dwarf minke whales. Minke whales are difficult to find in the open ocean because they produce small, inconspicuous blows when they surface to breathe. But now researchers can detect dwarf minkes using sensitive hydrophones to pick up the loud and distinctive star-wars vocalization.
"When you hear that sound, you know it's a minke whale, so we can use it to study their distribution, track their movements, and see how vocalizing animals are interacting with one another," Gedamke said.
There are several distinct forms of minke whales. The Northern Hemisphere and Southern Hemisphere forms are often considered separate species. The dwarf minke whale, although it occurs in the Southern Hemisphere, is more closely related to the Northern Hemisphere species. The dwarf minke is slightly smaller than the other forms, reaching about 30 feet in length.
Little is known about the vocalizations of Northern Hemisphere and Southern Hemisphere minke whales. In the Atlantic, a sound known as the "A train" has been recorded for decades and some researchers have attributed it to minke whales, but there have been few sightings of whales w
Contact: Tim Stephens
University of California - Santa Cruz