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Scientific News Biology To unknown science animals and plants STARTLING DEEP-SEA ENCOUNTER WITH RARE, MASSIVE GREENLAND SHARK.
STARTLING DEEP-SEA ENCOUNTER WITH
RARE, MASSIVE GREENLAND SHARK
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Huge Greenland shark as it approaches
Harbor Branch's Johnson-Sea-Link submersible
Credit: HARBOR BRANCH/Youngbluth
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During a recent submersible dive 3,000 feet
down in the Gulf of Maine a HARBOR BRANCH scientist and sub pilot had the first
face-to-face meeting ever in the deep sea with a rare Greenland shark. The
docile 15-foot creature gently rammed into the submersible's clear front sphere
before turning and swimming slowly away. The entire encounter was captured on
video, a clip of which can be viewed by clicking under the shark's photo at: http://www.at-sea.org/missions/maineevent4/day14.html
HARBOR BRANCH researcher Marsh Youngbluth and his
team were in the region studying a large jellyfish known as Nanomia cara, which
can cause commercial fish catch declines by out-competing fish larvae for
certain foods and by filling and fouling fish nets. He and submersible pilot Tim
Askew, Jr. were startled by the huge shark's appearance and feared at first that
it might damage the submersible or its scientific sampling equipment, though no
harm was done. After the shark swam away from the submersible Askew followed it
for several minutes.
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Swimming away from the submersible
Credit: HARBOR BRANCH/Youngbluth
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Though in the early 1900s Greenland sharks were
fished commercially, they have rarely been captured on video and never before
from a manned submersible in the deep sea or under natural conditions. All past
filming encounters involved sharks lured with bait or captured on fishing lines
and brought near the surface.
Greenland sharks, also called sleeper or gurry
sharks, have been known to grow as long as 21 feet, and are outsized only by
great white, basking, and whale sharks. Greenland sharks are poorly understood
but known for their lethargic swimming and a unique fishing technique. Small
marine crustaceans known as copepods generally attach themselves to the sharks'
eyes (and are visible in the new footage), possibly blinding them, but giving
off light that attracts curious fish.
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Gently ramming the Johnson-Sea-Link
submersible's acrylic front sphere
Credit: HARBOR BRANCH/Youngbluth
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It is not clear how the sluggish animals are able
to catch the fast-moving fish and squid commonly found in their stomachs. Some
scientists have theorized that the sharks are able to swim rapidly in bursts,
but there is also evidence that they are able to suck nearby fish into their
mouths. During the Gulf of Maine encounter, even after ramming into HARBOR
BRANCH's submersible, the shark continued to swim slowly. Greenland sharks also
eat seals, dead whales, and other animals, including in at least one documented
case, an entire reindeer. They are typically found in Arctic waters at depths
down to 1,800 feet, but have been recorded as far south as the coast of South
Carolina and at nearly 7,000 feet down.
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For more information please contact Mark
Schrope at 772-216-0390 or schrope@hboi.edu.
Photos and video of the shark encounter, which took place Sept. 25, are
available to illustrate stories about HARBOR BRANCH, and can be licensed for
other uses.
Contact: Mark Schrope, schrope@hboi.edu,
772-216-0390, Harbor
Branch Oceanographic Institution
The source of the given news and copyrights
belong to the Harbor
Branch Oceanographic Institution
Publishing date: October 21, 2003
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