Information was collected through the use of DTAGs (synchronous motion and acoustic recording tags) and Crittercam, National Geographic Society's underwater video and audio recording system.
"By visualizing the data with TrackPlot, we can actually see how the whale moves underwater and this enables us to discover different kinds of foraging behaviors," said lead author Colin Ware of the University of New Hampshire's Center for Coastal and Ocean Mapping. TrackPlot is a custom software tool for DTAG data that produces a ribbon-like image in three dimensions. "With these 3-D visualizations, we can follow the path of the whale from surface to seafloor along with all of the pitch, roll and heading changes while underway. By adding Crittercam video, we now get a more complete understanding of these various bottom feeding techniques," Ware said.
A side-roll is defined as a roll of between 45 and 135 degrees from a normal orientation along the seafloor the most common version uses a 90 degree roll with a downward head pitch of about 30 degrees, which matches favorably with earlier speculative sketches of bottom feeding. A side-roll inversion involves rolls that continue past the 135 degree orientation position. One humpback used a technique that employed a repetitive sequence of moves approximately every 20 feet during which the animal rolled from a 90 degree position to an inverted position, with some 10 to 17 of these "scoops" per dive.
Sand lance, also known as sand eels, tend to burrow into the sandy sediments at nig
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