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Bathydraconid
Hovering Video |
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Joseph
T. Eastman, Ph.D.
Professor of Anatomy
Department of Biomedical Sciences
eastman@ohiou.edu
119 Life Sciences Building
740-593-2350
Fax: 740-593-2400 |
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| View the video:
Bathydraconid Hovering Video |
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(playback requires
QuickTime or other movie player plug-in) |
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Explanation of the
bathydraconid hovering video
This video is supplemental material for a paper on
brain and sense organ morphology in Antarctic
dragonfishes of the family Bathydraconidae. The
video was taken at Station 34 (77°04’S, 165°10’E),
28 December 1997 during cruise 97-9 of the RV
Nathaniel B. Palmer. The station was located in
the Drygalski Basin in the southwestern Ross Sea,
Antarctica. Although close to the coast, this 1,200
m-deep basin is one of the deepest areas in the Ross
Sea. The camera system was design and operated by
Dr. James Barry of the Monterey Bay Aquarium
Research Institute. Suspended from a towline, the
camera was maintained about 2 m above the sea floor
and a 0.5-m visual scale was mounted vertically on
the anchor chain and weight. Bottom temperature at
this site was –1.8°C and the substrate was soft
sediment with occasional boulders. The initial
frames of the video show the sediment being
disturbed by the weight as it moves across the
bottom.
The fish appears to the right of the tow line about
12 seconds after the video begins. It is identified
as the bathydraconid Bathydraco macrolepis on
the basis of body shape, size and banding pattern.
This species was also captured in a trawl at Station
34. Based of the drift of illuminated plankton
visible in the original copy of the video, the fish
is heading into the current and is about a meter
above the substrate. It maintains position by rapid
up and down strokes of the pectoral fins. In these
frames the camera lights also cast a shadow of the
fish on the bottom. A few seconds later the fish is
startled by the anchor weight dragging across the
bottom and swims away using subcarangiform
locomotion.
Little is known about the diet and feeding habits of
most species in the deep-living tribe
Bathydraconini exemplified by Bathydraco
macrolepis. The hovering behavior seen in the video
may be a common foraging strategy in this group, and
the video also provides a glimpse of the limited
benthic resources and sensory environment at this
depth. The invertebrate fauna, consisting of
ophiuroids, holothurians and sponges, is sparse
although it is more abundant on rocks seen near the
end of the video. |
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