Somniosus microcephalus
(Bloch and Schneider) 1801

The Greenland shark is the largest member of the Somniosidae family. It is the second largest* carnivorous shark after the great white and it is the largest Arctic fish. Its range extends from the Arctic to Georgia. It reaches an enormous size and despite its lethargic appearance, it is a swift predator that hunts seals and even larger mammals. The Greenland shark is very rarely observed because of its bathybenthic environment that is inaccessible to divers. The first underwater photos of a live specimen were taken in the Arctic in 1995, and the first video images of a shark swimming freely under natural circumstances were filmed by the current GEERG team in 2003 in the St. Lawrence Estuary. *(equal length)

Scientific Name:
Somniosus microcephalus* (Bloch & Schneider, 1801)
somniosus : from the latin [somnus] + [osus] = sleep (full of)
microcephalus : micro + greek [kephalē] = small head
*Smallheaded sleeper

Common Names:
Greenland shark
Sleeper shark
Ground shark
Grey shark
Gurry shark
Requin du nord (Fr.)

Requin du Groenland (Fr.)
Laimargue (Fr.)
Requin noir (Fr.)
Skalugsuak (Inuktitut)
Iqalugjuaq (Inuktitut)
Requin dormeur (Fr.)
Requin de fond (Fr.)
Requin de glace (Fr.)

The Greenland shark is often called the «Bottom shark» by St. Lawrence and Saguenay fishermen in Quebec.

Its 2 dorsal fins are small and spineless. The base of the dorsal fins is shorter than their lengths. The caudal fin is assymetrical. Its eyes are round and small and are usually host to a parasite, except in the case of the St. Lawrence specimens observed by GEERG in 2003 & 2004, which had no parasites.

The shark's skin can be black, brown, grey, or a spotted mix of all three. Its whitened snout (see photo) is a sign of repeated abrasion resulting from the foraging sharks' quest for food on the sea floor. Photo © Jeffrey Gallant (All Rights Reserved)

A Greenland shark hanging off the dock at Les Escoumins, one of Quebec's most popular sport diving destinations. Photo courtesy Luc Tremblay (All Rights Reserved)

The distribution of the Greenland shark extends from the Arctic and Northern Europe, south to Georgia, including the St. Lawrence Estuary and Saguenay Fjord. In fact, this is the only shark that can tolerate Arctic temperatures yearround. Its presence has been recorded in every season in the Saguenay Fjord, not only in winter as is widely believed. Considering the cold temperatures and the depth of the fjord (close to 300m) this is entirely plausible.

Water temperature is a crucial factor for this shark's comfort zone. It prefers very cold water (-0.6°C to 12°C) and seasonal variations determine its migration up or down the water column. In the summer, the shark is normally found at great depth (up to 2,200m*) where the water is coldest. In winter, it rises to the surface layer, which is colder than the water on the sea floor.

GEERG observations of the Greenland shark since June 2003 put into question many of the long accepted theories about the Greenland shark's seasonal and daily migrations throughout the water column.

* Observed from a submersible on the wreck of the SS Central America (1988)

Little research has been done on the Greenland shark's reproduction. It is ovoviviparous: its eggs develop and hatch inside the female. The female gives birth to at least 10 pups at a time each measuring approximately 40 cm. Mating and birth have never been observed.

Females observed by GEERG in the St. Lawrence all had mating scars on their caudal area (see photo). When the male decides to mate, it bites the female into submission. Fortunately for the female, its skin is twice as thick as the male's.

The parasite most commonly associated with the Greenland shark is the copepod Ommatokoita elongata. It latches itself to one or both of the shark's eyes which causes lesions to the cornea and can render the shark partly blind. However, even if it was completely sightless, the Greenland shark could easily survive using its other senses to detect and localise prey.

Also, since the shark lives at great depth and often under ice, its habitat is normally devoid of light rendering its eyes useless. Certain researchers believe the copepod is bioluminescent and serves to attract prey to the shark but this has never been proven. It is interesting to note that while over 85% of Arctic populations of the Greenland shark parasited by the copepod, few of the sharks encountered by GEERG researchers in the St. Lawrence are hosts of Ommatokoita elongata.

The Greenland shark's dentition determines its feeding technique. The upper teeth, pointy but not serrated, enable the shark to pin its food into position. The bottom teeth, wide and curved sideways, serve to cut the food item by swinging the head in a circular motion. By doing so, the shark cuts out a «cork» of flesh from its victim when it is too large to swallow whole.

This behaviour was recorded by Dr. George Benz on Baffin Island, and this type of injury is the trademark signature of the Greenland shark (See Sable Island). The upper teeth number 48 to 52 while the lower teeth number 50 to 52. Small prey items that fit into the shark's mouth whole are simply sucked off the bottom.

Jean-Yves Forest with satellite tag for Greenland shark. Photo © Maude Roussel (All Rights Reserved).

Very little research is presently being conducted on the Greenland shark. In Canada, GEERG and SRI Canada are pursuing various research projects in the St. Lawrence Estuary and the Saguenay Fjord. On the East Coast, the Canadian Shark Research Laboratory conducts research on Greenland shark specimens captured by the fishing industry.

GEERG researchers are particularly interested in the shark's distribution in the St. Lawrence and Saguenay systems as well as in its behaviour under natural circumstances.

The cost of mounting expeditions to conduct field studies is very high, and funding for such endeavours is extremely rare since this species has practically no commercial value, hence it generates little interest. GEERG thus relies on the support of the diving community, the coastal population, active and retired fishermen, and our partners and sponsors.

In certain countries, the Greenland shark is still hunted commercially for its oil. Between the latter half of the 19th century and 1960, fishermen in Greenland and Iceland caught up to 50,000 sharks annually. The oil contains Vitamin A and was used to light lamps.

Because its flesh is non-edible, the carcass was dumped overboard into the ocean where it fed other sharks. The shark's flesh contains so much urea that it must undergo a long and unpleasant process before it can be fed to sled dogs. Foregoing the process makes the dogs enter a drunken-like state called « shark sick » . High levels of intoxication lead to convulsions, or even death.

In Iceland, shark meat is processed to perfection, cut into bite-sized cubes, and served as an hors-d'oeuvre called hakárl or kæstur hákarl.

Shark caught by ice fishers in the Saguenay Fjord in 1996. Fishing the Greenland shark is now illegal. Photo courtesy Musée du fjord

Unlike the god-like reverence for sharks prevalent in the South-Pacific, Westerners hold little appreciation for these toothed monsters. Generally perceived as indiscriminate killing machines, this isn't usually the case for the Greenland shark, at least not by certain fishers that mockingly call it the « bottom shark » and consider it to be completely harmless.

Even worse, certain fishers consider it a pest that damages their nets and that contributes to the decline of fish stocks. Pity the shark that is caught by these fishers who cut off their caudal fin and toss the shark overboard to a certain and pointless death.

The overall public perception on sharks isn't much better. Thanks to sensationalistic documentaries and movies such as « Jaws », which largely prevailed until recently, few people have any sympathy for sharks although most gaze in awe at the sight of the beast hanging from a hook at the local wharf. Like them or not, few animals generate so much media frenzy and genuine fascination. GEERG aims to reverse this baseless and destructive trend with ground-breaking research and public-awareness.

Inuit woman, circa 1907.

SKALUGSUAK
The Greenland Shark's tissue has a high urea content, which gave rise to the Inuit legend of the shark's origin: An old woman washed her hair in urine and dried it with a cloth. The cloth blew into the sea and there it became Skalugsuak, the first Greenland Shark.

SEDNA
When a young Inuk girl told her father she wanted to marry a bird, he killed her fiancé and threw his daughter into the sea from a kayak. When she hung on to the side, he cut off each of her fingers until she let go. Sedna slid into the depths where she became the goddess of the sea. Each of her fingers turned into a sea creature, including the Greenland shark. The shark was entrusted with the duty to avenge the goddess and one day, it capsized the father's kayak and ate the man while he was fishing. When an Inuk dies in this fashion, the locals say the shark was sent by Sedna.

The Greenland shark is not listed as a threatened species by COSEWIC (Committee on the Status of Endangered Wildlife in Canada). However, its numbers in the St. Lawrence and Saguenay are still unknown.

---------------------------------------------------------

The Greenland shark is listed as Near Threatened by the IUCN Red List (International Union for the Conservation of Nature and Natural Resources).

Click HERE to go to the IUCN Red List web page on the Greenland shark.

COPYRIGHT GEERG 2009 / ALL RIGHTS RESERVED
info@geerg.ca

Should the Greenland Shark be turned into biofuel?
A recent proposal in Greenland would see Greenland shark bycatch turned into a new energy source in the form of bio-fuel. Proponents of the idea believe that shark meat...



Jeffrey Gallant is appointed as Managing Director of SRI Canada
GEERG director, Jeffrey Gallant, has been appointed as the managing director of SRI Canada. Shark Research Institute (SRI), a multi-disciplinary non-profit 501(c)(3) scientific research organization...

Sign up for important updates, corrections and new records. Name Email