Since 2001, the Greenland Shark and other Elasmobranch Research and Education Group, led by Canadian researchers, has been studying the Greenland shark in the waters of the Saguenay Fjord and the San Lorenzo Estuary. The presence of this species in the area has been repeatedly documented since 1888.
The researches undertaken by the GEERG involve the study of shark behavior thanks to the use of both divers equipped with television cameras and acoustic and satellite signaling equipment positioned on the sharks themselves; despite all the studies carried out, however, this giant of the sea still remains almost unknown.
The Greenland shark meat is poisonous, due to the presence in it of a toxin, trimethylamine oxide, which, if digested, breaks down into trimethylamine, a substance that causes effects equal to those of a strong intoxication.
Because of this neurotoxin, sled dogs that have eaten this shark's flesh can no longer stand.
Complexity and curiositiesof the Greenland Shark
However, if it is boiled by changing the water often or if it is dried and fermented for a few months to produce the so-called Kæstur Hákarl, also called simply Hákarl, it can be consumed.
Traditionally the preparation of the latter is done by burying the shark in boreal soils and leaving it exposed to various freezing and thawing cycles; the product of the process is considered a delicacy in Iceland and Greenland.
Similar toxic effects are also given by the meat of the Pacific lemargo, but not by those of the majority of sharks, whose meat is often eaten fresh. The Greenland shark feeds mainly on fish, but it can also take marine mammals such as seals.
Reindeer remains have also been found in the stomachs of some specimens. The shark itself is colonized by parasitic copepods which, while attacking the cornea, allow the shark to attract prey by their bioluminescence. It is the longest-lived vertebrate in the world.
An age of 512 years has been estimated for the oldest specimen. The Greenland shark reaches maturity around 150 years of age. Its poisonous meat, with a high urea content, is the basis of the legend of Skalugsuak, the first Greenland shark.
According to this legend, an old woman washed her hair with her own urine and dried it with a rag; from this rag, thrown into the ocean, Skalugsuak originated. Another legend is that of Sedna, a girl whose fingers were cut off by her father while he was drowning. It is said that each severed finger of hers gave rise to a creature of the sea, including the Greenland shark.