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Wednesday, August 5, 2009

Sea Things #9: Greenland Shark

Sea Things is a regular feature on my blog where I profile a different sea creature. Look for it weekly, or something close to weekly.


What's this?  A second Sea Things in the same week?  Nutty!  I just felt like my last couple of sea things (Lionfish and Caribbean Reef Shark) had been so much about conservation and some of my own frustrations over people just NOT CARING about reefs and oceans.  I wanted to have another Shark Week post that focused on an incredible, fascinating shark, which I only learned about several months ago.  This is the Greenland Shark.






In February, 2009, Todd and I went to a seminar on the Greenland Shark, which was hosted by our local dive shop, and was presented by National Geographic Photographer and Maryland native Nick Caloyianis.  While usually for my Sea Things feature I prefer to stick to creatures that I have seen and interacted with myself, I have my doubts that I will ever encounter a Greenland Shark, and they are just too facinating to not discuss.  During the presentation, I must admit that I was totally spellbound.  What interesting animals!


Nick Caloyianis went to Baffin Island, Canada to find these sharks, which until his trip there, had been studied very little.  No photographs had ever been taken of a living one in its natural environment.  He wasn't certain he would find them, and the expedition had been delayed by two weeks of storms.  Finally, diving in 28 degree water, he found one:


A dull outline formed in the murky distance. It was a long animal. Huge. My diminished senses perceived it to be a narwhal, without its unicorn-like tusk.
Forget the cold. I kicked my fins and swam toward the shadowy figure. It turned and began moving toward me. I was face-to-face with a Greenland shark. I’d seen drawings and paintings of the fish, but this was utterly different. It was ghoulish. Its nostrils were the largest I had ever seen on a shark. They reminded me of a giant double-barreled shotgun. Its mouth was slightly open, revealing rows of small sharp teeth. Its eyes looked fogged over, like those of a dead fish, and from each one dangled a tasseled parasite.

Greenland Sharks are one of the largest in the world.  They rival the Great White in size, growing to 21 feet and 2000 pounds.  They live in the Arctic, sometimes traveling South as far as the Gulf of St. Lawrence, but tend to stay in the Arctic Ocean (the main reason why I doubt I'll ever see one...  brrr!).  They are thought to often live in deep water, as deep as 2000 feet, which is well beyond the depth of other sharks.  


The sharks have a parasite that attach themselves to each eye.  The parasites are called copepods, and hang from the sharks' corneas.  The copepods make the sharks blind, but since the sharks live in near darkness beneath Arctic ice, it is not usually a problem.  In fact, it is thought that it is a symbiotic relationship - the parasites glow with a bioluminecence that attracts prey (such as seals) to them.  Once the prey gets close enough, the sharks sense that it is there and can suck them in from up to 3 feet away.  


A closeup of the copepod on a Greenland Shark's eye:




Greenland Sharks eat seals, sea lions, halibut, herring and salmon, and sometimes are cannibalistic.  Despite the fact that they sometimes eat fast swimming fish, they are actually quite slow and sluggish swimmers.  As for what eats Greenland Sharks?  Nothing.  There is absolutely no danger of Greenland Sharks becoming part of a chinese food menu, as other sharks have become -  Greenland Shark meat is poisonous.  Caloyianis, during his presentation, described how the local Inuits do not eat the meat (although do sometimes kill the sharks because they are considered a nuisance).  The Inuits fed some of the shark meat to their dogs, which became drunk with a neurotoxin in the shark meat.  


These are some crazy-interesting sharks, and I would love it if Discovery had included a documentary about them in their Shark Week lineup.  I realize that one big reason this isn't possible is that most of the info on Greenland Sharks was gathered for an issue of National Geographic, but maybe the NatGeo Channel will make the documentary I'd love to see...  Well, it was better having met the diver in person anyway.






Is there a creature that you would like to see featured in Sea Things? If so, shoot me an email and if I can, I'll write about it.

1 comment:

Anonymous said...

Hi Kim,

We've been studying and diving with the Greenland shark for several years in the St. Lawrence Estuary. Many documentaries and reports have been produced on our work. "Searching for a Monster" was the first documentary (2003) and it has been broadcast on Discovery Channel Canada since its release. It took Second Place at the Belgrade Underwater Film Festival in 2004. Have a look at our website (http://www.geerg.ca) for more info on the Greenland shark and our research.

Best regards,

- Jeffrey (info@geerg.ca)

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