Tuesday, April 10, 2012

Deep Sea Sharks

Deep sea sharks live mostly in the bathypelagic zone of the ocean. This zone, anywhere between 1,000 meters to 4,000 meters from the surface of the ocean, is completely void of any sunlight. Around 400 species of deep-sea shark have been discovered. Of those, most is known about the following three:











The shark to the right is the Bluntnose Six-gill shark, the most well known deep sea shark. This shark is dark on top to blend in with the darker ocean depths and light on the bottom to blend in with lighter tones closer to the surface. Found in tropical and temperate seas, they eat rays, bony fish, crabs, shrimp, and even seals up to 2500m below the surface.





This video above shows a rare six-gill shark sighting at 3300m.







This shark is the frilled shark, named so because of its six "frilly" gills. They have poorly-calcified skeletons and large livers filled with low-density lipids, which allows them to maintain their low position in the ocean with minimal effort. This species is one of the most primitive sharks because it hasn't evolved for thousands of years.







The shark to the right is the goblin shark, a shark that adapted to deep-sea life early in its evolutionary history. Its most distinctive characteristic is its head: it has a long trowel-shaped snout. It also has a protrusible jaw, which it sticks out when it preys on food (shown in the picture). Despite the bathypelagic zone's significantly low biomass, this shark is able to maintain its considerable mass.The video below shows the shark as it sticks out its jaws.




By Binny Kim & Kiyon Hahm

References cited:
http://dsc.discovery.com/sharks/goblin-shark.html
http://marinebio.org/spcies.asp?id=1485
http://www.arkive.org/bluntnose-six-gill-shark/hexanchus-griseus/image-G17861.html
http://www.teara.govt.nz/en/deep-sea-creatures/1/5
http://www.arkive.org/bluntnose-six-gill-shark/hexanchus-griseus/video-00.html
http://www.youtube.com/watch?v=GjRSlnJ1rA4
http://marinebio.org/species.asp?id=1485
http://www.marinebio.org/species.asp?id=88
http://www.marinebio.org/species.asp?id=234
http://www.arkive.org/bluntnose-six-gill-shark/hexanch-griseus/
http://www.elasmo-research.org/education/ecology/deepsea-goblin.htm
http://www.deepseamonsters.com/component/content/article/59-frilled-shark.html
http://www.elasmo-research.org/publications/pdfs/deep-sea-sharks.pdf


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