LAST UPDATED: 21.10.2023

LAST UPDATED: 21.10.2023

GREENLAND SHARK

GREENLAND SHARK

Somniosus microcephalus

Somniosus microcephalus

The Greenland shark is the largest member of the Somniosidae family. It is the second-largest¹ carnivorous shark after the great white and it is the largest Arctic fish. It is also the longest-living vertebrate animal with a life expectancy of at least 272 years². Its range extends from the Arctic Ocean and Northern Europe to the 32nd parallel north in the Atlantic Ocean. Despite its lethargic appearance, it is a predator capable of short bursts of speed, and under certain conditions may hunt seals and even larger mammals including the beluga whale.

The Greenland shark is very rarely observed because of its bathybenthic habitat that is inaccessible to scuba divers. The first underwater images of a live specimen were taken in the Arctic in 1995, and the first images of a Greenland shark swimming freely under natural circumstances³ were filmed by GEERG in the St. Lawrence Estuary in 2003.

¹ Equal length as the white shark but approximately half the girth.
² Nielsen, J., Hedeholm, R. B., Heinemeier, J., Bushnell, P. G., Christiansen, J. S., 2815 Olsen, J., et al. (2016). Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus). Science 353, 702–704.
³ Non-invasive shark observation conducted without the use of attractants, capturing, or restraints. All encounters initiated and terminated by the sharks.

Order – Lamniformes
Family – Somniosidae
Genus – Somniosus
Species – S. microcephalus

NAMES

NAMES

Common names: Sleeper shark, ground shark, grey shark, gurry shark.

Inuktitut names: Skalugsuak, Ekalugssuaq, Iqalugjuaq.

French common names: Requin du nord, requin noir, requin dormeur, requin de fond, requin de glace.

Scientific Name: Somniosus microcephalus* (Bloch & Schneider, 1801) — Somniosus: from the Latin [somnus] + [osus] = sleep (full of); microcephalus : micro + Greek [kephalē] = small head; Meaning: *Smallheaded sleeper

What’s in a Name?

What’s in a Name?

In spite of its appellation, the Greenland shark is not endemic to Greenland, nor is it unusual to find it elsewhere. It is just as home in the St. Lawrence and the Saguenay as it is in the Arctic Ocean.

GENERAL DESCRIPTION

GENERAL DESCRIPTION

• Averages 3 to 5 metres long, but can reach up to 7 metres.
• Variably coloured (brown, purplish grey, slate grey or black) and mottled in appearance.
• Skin often bears white marks caused by entanglements or mating. Offers little resistance when caught.
• First dorsal fin positioned farther back on body and slightly larger than the second.
• Spineless dorsal fins, the rear tips of which are not attached to the back.
• Lacks anal fin.
• Asymmetrical caudal fin (tail) with slightly larger top lobe.
• Year-round presence in Atlantic Canada and Quebec, including the St. Lawrence Estuary and the Saguenay Fjord. Only shark species that can tolerate arctic waters all year long.

3 to 5 m in Atlantic Canada and Québec

Teeth are large, triangular and serrated unlike any other shark species in the St. Lawrence.
JAWS
Eyes of the Greenland s. in the St. Lawrence are typically devoid of the parasitic copepod, Ommatokoita elongata.
OCULAR PARASITE
Dermal denticles reduce drag and turbulence, which enables the shark to swim more stealthily.
DERMAL DENTICLES
Single keel on the caudal peduncle unlike the porbeagle shark which has two.
CAUDAL KEEL
The whitened rostrum is a sign of repeated abrasion resulting from the foraging on the sea floor.
WHITE ROSTRUM

DISTRIBUTION

DISTRIBUTION

The distribution of the Greenland shark extends from the Arctic Ocean and Northern Europe to the 32nd parallel north in the Atlantic Ocean, including the St. Lawrence Estuary. It is one of only two sharks (with the Pacific sleeper shark, Somniosus pacificus) known to tolerate Arctic temperatures year-round. In the province of Québec, its presence has been recorded throughout the Saguenay Fjord, and it has also been observed in the lower reaches of Hudson Bay (James Bay) (Gallant, unpublished data).

The Greenland shark inhabits cold-water environments (-1.6°C to 16.1°C)¹ although seasonal variations determine its migration up or down the water column. In the summer, it spends more time at depth where the water is coldest. In winter, it often rises to the ice-covered surface layer, which is colder than the water on the sea floor.

St. Lawrence: Although Somniosus microcephalus is commonly known as the Greenland shark, its presence in the Gulf of St. Lawrence, which has been documented for nearly two centuries, is neither recent nor is it related to climate change.

Gulf of Mexico: DNA testing² contradicts the reported capture of a Greenland shark in the Gulf of Mexico in 2013. The shark caught by Florida State University was either Somniosus pacificus or a hybrid sleeper shark.

Note: Because it is virtually impossible to visually differentiate sleeper shark species, and because their distributions overlap, reported sightings of Greenland sharks from submersibles and ROVs cannot be confirmed.

(BELOW) Provisional worldwide distribution of the Greenland shark, Somniosus microcephalus, based on research by the St. Lawrence Shark Observatory. Only historical and select cases are posted to illustrate overall range. This map is updated with new and historical data on an ongoing basis. To submit additional sightings or captures, please contact us. Click on icons for observation details.

DENTITION

DENTITION

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 round “plug” of flesh from its victim when it is too large to swallow whole. This behaviour was recorded on film by Dr. George Benz on Baffin 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.

Note: The documented plug-like wound mentioned above is not to be associated with the so-called “corkscrew” wound which has been reported by the media and in a documentary film in 2010. The corkscrew wound on seals more likely caused by other seals¹.

¹ Brownlow A, Onoufriou J, Bishop A, Davison N, Thompson D (2016) Corkscrew Seals: Grey Seal (Halichoerus grypus) Infanticide and Cannibalism May Indicate the Cause of Spiral Lacerations in Seals. PLoS ONE 11(6): e0156464. doi:10.1371/journal.pone.0156464

SKIN

SKIN

The skin of the Greenland shark is covered in dermal denticles, which are more like teeth that fish scales. The denticles reduce drag and turbulence, and this enables the shark to swim more stealthily. The denticles are very sharp. Divers must therefore avoid intentional or accidental contact with a Greenland shark as the denticles may damage or even pierce a drysuit.

DEPTH RANGE

DEPTH RANGE

Greenland sharks have been visually recorded from the surface (0 m) down to 2,200 m¹ near the wreck of the SS Central America (recorded by an unmanned submersible 260 km east of Cape Hatteras) in 1988². The pressure at the location off North Carolina was 3,203 PSI (221 BAR), which is beyond the safe operating limit of many scuba tanks. For the sake of comparison, the pressure inside the tires of most passenger cars is between 32 to 35 PSI. A sleeper shark—species unknown—was observed at the depth of 2,774 m off the coast of Brazil in 2012.

¹ The species of sleeper shark observed at 2,200 m (1998) is unconfirmed although it is generally assumed to be a Greenland shark due to the location.
² Herdendorf, C. E., and Berra, T. M. (1995). A Greenland shark from the wreck of the SS Central America at 2,200 meters. Trans. Am. Fish. Soc. 124, 950–953.

SWIMMING SPEED

SWIMMING SPEED

The Greenland shark is one of the slowest swimming sharks in the world. In fact, we have often observed Greenland sharks practically hovering over the bottom, almost immobile, but how slow is it really? Based on our hundreds of visual observations of free-swimming Greenland sharks, and having carefully analysed hours of video images as well as several months of telemetry data, we have determined that the average swimming speed of the Greenland shark in the St. Lawrence Estuary is 0.3 metres per second, or 1.08 km/h (0.67 mph)¹. We have also observed burst speeds up to 1 metre per second, or 3.6 km/h (2.2 mph), during tagging operations by scuba divers on unrestrained Greenland sharks.

Greenland shark in the St. Lawrence Estuary. Video © ORS | Jeffrey Gallant and Chris Harvey-Clark. All Rights Reserved.

A published top speed of 0.7 m/s (1.7 mph)² for this species was measured under normal circumstances when the sharks tagged with accelerometers weren’t being stung by divers equipped with spears. And although at times it does take “seven seconds for a single full tail sweep to propel the shark forward” (BBC Nature, June 22, 2012), this does not apply to a Greenland shark’s average swimming speed as is clearly demonstrated in the accompanying video.

¹ Gallant, Jeffrey J., Marco A. Rodríguez, Michael J. W. Stokesbury, and Chris Harvey-Clark. (2016). Influence of environmental variables on the diel movements of the Greenland Shark (Somniosus microcephalus) in the St. Lawrence Estuary. Canadian Field-Naturalist 130(1): 1-14.
² Watanabe, Y. Y., Lydersen, C., Fisk, A. T., and Kovacs, K. M. (2012). The slowest fish: Swim speed and tail-beat frequency of Greenland sharks. Journal of Experimental Marine Biology and Ecology 426–427: 5-11.

World’s Slowest Shark?

World’s Slowest Shark?

The Greenland shark is by no means a race car, but there have been many occasions when physical overexertion has prevented us from keeping pace with one for more than 1-2 minutes while scuba diving. Unless the Greenland shark is only compared to other shark species or fish of the same size, and for all of the reasons stated above, we thus do not believe that it is the world’s slowest shark, let alone the world’s slowest fish.

As for other species vying for the title of the world’s slowest shark—and discounting burst speeds—a study¹ demonstrated that Pacific angel sharks, Squatina californica, covered distances of no more than 30 to 75 km (19 to 47 miles) over a period of three months, or at most 7.3 km (4.5 miles) in a single night, while one Greenland shark tagged by GEERG in 2005 covered 26 km (16 miles) in just 29 hours². Both species use their spiracles³ to assist with breathing and both species have exhibited site fidelity (philopatry) over a period of months, or even years. Granted, angel sharks don’t migrate and they aren’t the most active swimmers so it may be an unfair comparison. So what about the other sleeper sharks and deep-sea dogfishes such as the dwarf lanternshark and gulper sharks? Any one of them could win—or should it be lose?—by a snout!

Until recently, few people in the entertainment industry or in the media have shown interest for the allegedly characterless Greenland shark. In the absence of definitive proof or a clear scientific definition, the title of ‘World’s Slowest Shark’ may therefore be an attempt at attracting media attention to this much overlooked species. Scientific rigour precludes us from making such a bold statement.

¹ Fouts, W.R. & Nelson, D.R. (May 7, 1999). “Prey Capture by the Pacific Angel Shark, Squatina californica: Visually Mediated Strikes and Ambush-Site Characteristics”. Copeia. American Society of Ichthyologists and Herpetologists. 1999(2): 304–312.
² Gallant, Jeffrey J., Marco A. Rodríguez, Michael J. W. Stokesbury, and Chris Harvey-Clark. (2016). Influence of environmental variables on the diel movements of the Greenland Shark (Somniosus microcephalus) in the St. Lawrence Estuary. Canadian Field-Naturalist 130(1): 1-14.
³ Unlike the many shark species that must constantly swim to force oxygen through their gill openings, some sharks can remain motionless for long periods while they use their spiracles to extract oxygen from the water. Among these, the Greenland shark has unusually large spiracles that allow it to take in oxygen while swimming at reduced speed either to hunt by stealth or to conserve energy in its near-freezing environment.

PREY

PREY

The Greenland shark is an opportunistic predator that will eat just about anything that comes across its path, either dead or alive. However, we believe that it is primarily a scavenger.

Verified stomach contents

Fish: Arctic char, Atlantic halibut, Atlantic salmon, capelin, cod, eelpout, eels, Greenland halibut (turbot), grenadier, haddock, herring, lumpfish, lycodes, pollack, sculpins, sebastes, skates and other sharks, spotted wolffish.

Mammals: beluga, narwhal, porpoise, seals, and other animals including a dog, horse, reindeer, moose, and white (polar) bear remains.

Invertebrates: crustaceans, gastropods, jellyfish, octopus, sea stars (sun stars & brittle stars), squid, urchins, whelk and other snails.

Others: Bird remains, kelp.

Non-verified prey

Mammals: The Greenland shark has reportedly been seen by scientists, hunting caribou in the manner of a crocodile ambush at river mouths in the Canadian Arctic. Note: Although this much-publicised anecdote comes from a credible source, it has never been substantiated. More than likely, the Greenland shark feeds on drowned caribou that fell through the ice while migrating.

Contrary to what was reported by the media in 2008 and had since been propagated via social networks, global warming is also unlikely to help the Greenland shark attack bears. Reuters: Polar bear eaten by shark. Who’s top predator?

“There is little chance that a Greenland shark could predate a live adult white (polar) bear unless it were injured or seriously ill. The Greenland shark simply cannot afford the risk of injury nor the expenditure of energy required to kill such a large and dangerous animal, with or without the help of global warming. There is far easier prey to be found.”

— Jeffrey Gallant | St. Lawrence Shark Observatory

PREDATORS

PREDATORS

The only confirmed predator of the Greenland shark is the sperm whale (Physeter macrocephalus). GEERG has recorded two occurrences of a sperm whale exhibiting predatory behaviour while in the presence of the Greenland shark in the St. Lawrence Estuary. Unfortunately, the same whale—known as Tryphon—died of entanglement in fishing apparatus in 2009.

Further investigation by GEERG (2009) led to the discovery of another potential indicator that this particular sperm whale could have been feeding on Greenland sharks for several years.

Photo analysis revealed that Tryphon’s teeth were severely eroded from abrasion. The same dental anomaly was observed in a pod of orcas (Orcinus orca) feeding¹ on Pacific sleeper sharks (Somniosus pacificus) off British Columbia in 2008. The Pacific sleeper shark is practically identical to the Greenland shark.

Orcas and sperm whales are believed to feed on sleeper sharks mostly for the large quantity of oil found in their livers. However, the hunters must first tear apart their prey with their teeth which are thus eroded by the sharp denticles that cover the shark’s skin.

Feeding on sharks in this fashion over a period of several years would likely accelerate tooth wear thus transforming the predator’s normally sharp teeth into rounded stubs.

¹ Ford, J.K.B., G.M. Ellis, C.O. Matkin, M.H. Wetklo, L.G. Barrett-Lennard, and R.E. Withler. 2011a. Shark predation and tooth wear in a population of northeastern Pacific killer whales. Aquat. Biol. 11: 213-224.
(ABOVE CLOCKWISE) Sperm whale Tryphon with eroded teeth (© René Trépanier). One of Tryphon‘s teeth (© GREMM). Orca with teeth worn flat to the gum line, exposing the pulp (Robin Abernethy | DFO). (BELOW) Tryphon echolocating in the close vicinity of Greenland sharks (© ORS | Jeffrey Gallant)

REPRODUCTION

REPRODUCTION

Little research has been done on the Greenland shark’s reproduction although it is believed to reach sexual maturity at the age of 156 ± 22 years¹. Since the female gives birth to at least 10 pups at a time, some researchers believe that it is viviparous: Its eggs develop and hatch inside the female where the pups are fed by a placenta. The Greenland shark is believed by others to be ovoviviparous (aplacental viviparity): Its eggs also develop and hatch inside the female but there is no placenta. The pups thus feed on each other so few survive until birth. Although mating and birth have never been observed, newborn pups are believed to measure approximately 40 cm.

Females observed by GEERG in the St. Lawrence mostly have mating scars on their caudal area. 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.

¹ Nielsen, J., Hedeholm, R. B., Heinemeier, J., Bushnell, P. G., Christiansen, J. S., 2815 Olsen, J., et al. (2016). Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus). Science 353, 702–704.

LIFE EXPECTANCY

LIFE EXPECTANCY

The Finnish proverb stating that “Age does not give you good sense, it only makes you go slowly,” may hold some truth with the Greenland shark. With an average cruising speed of 0.3 m/sec (1 ft), the Greenland shark is indeed a very relaxed swimmer. Its unusually slow metabolic rate may be attributed in part to its frigid living environment, which may also help explain the latest discovery¹ on this mysterious northerly predator.

Until recently, aging a Greenland shark was impossible since it does not have vertebral growth bands—counted like rings on a tree—as do many other shark species. Therefore, determining its age would require the capture and measurement of a newborn pup followed by periodical recapture and measuring until the end of its natural life. Doing so under controlled conditions—no Greenland shark has ever been kept in captivity for more than a month—would not reflect the natural growth rate of a shark living in an oceanic environment, and a study in the wild over a long period, say 200 years, would require several generations of researchers as well as an extreme range and ongoing tracking system, the likes of which does not yet exist.

Even today, very limited information exists on recaptured sharks, and the only science paper with reliable recapture data is over fifty years old. In that study¹, a shark that was captured and tagged off Greenland in 1936 was recaptured in 1952. In 16 years, the shark’s length had only increased by eight centimetres (3 in), or 0.5 cm (0.2 in) per year. Two less reliable reports in the same paper obtained from sharks recaptured after two and 14 years suggest growth rates of no more than 1.1 cm (0.43 in) per year, or approximately 0.3 m (1 ft) per 30 years. Assuming the rate is constant—no growth spurts—a fully-grown Greenland shark could theoretically be well over 500 years old.

The Greenland shark’s suspected yet hypothetical longevity was apparently confirmed in a study² released in August 2016 by a science team led by Julius Nielsen at the University of Copenhagen. According to the article published in the journal Science, the scientists used radiocarbon dating to establish the age of 28 Greenland sharks. The age ranges of sharks born before atomic bomb testing in the 1950s—which nearly doubled the amount of carbon-14 in the atmosphere—revealed a life-expectancy of at least 272 years, that sexual maturity may not be reached before 156 ± 22 years, and that the largest shark (5.2 m / 17 ft) was 392 ± 120 years old. Considering that the largest known length for the Greenland shark is over seven metres (23 ft), there may be living specimens that were swimming in the St. Lawrence when Jacques Cartier laid claim to New France in 1534. Although scientific debate on this discovery may linger for years—radiocarbon dating of deep-dwelling marine organisms is not very precise—, it is safe to say that even with the most conservative margin of error, the Greenland shark is currently and by far the longest-living vertebrate on the planet.

¹ Hansen, P. M. (1963). Tagging experiments with the Greenland shark (Somniosus microcephalus (Bloch and Schneider)) in subarea 1. Int. Comm. Northwest Atl. Fish. Spec. Publ. 4, 172–175.
² Nielsen, J., Hedeholm, R. B., Heinemeier, J., Bushnell, P. G., Christiansen, J. S., 2815 Olsen, J., et al. (2016). Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus). Science 353, 702–704.

PARASITES

PARASITES

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 90% of Arctic populations of the Greenland shark parasited by the copepod¹, less than 5% of the sharks encountered by GEERG researchers in the St. Lawrence² are hosts of Ommatokoita elongata.

In 2004³, GEERG researcher Jeffrey Gallant observed a sea lamprey (Petromyzon marinus) parasiting a Greenland shark near Baie-Comeau, in the St. Lawrence Estuary.

¹ Koefoed E (1957) Notes of the Greenland shark Acanthorhinus carcharias (Gunn). 2. A uterine foetus and the uterus from a Greenland shark. Rep Nor Fish Mar Investig 11:8–12.
² Harvey-Clark, C. J., Gallant, J. J., and Batt, J. H. (2005). Vision and its relationship 2612 to novel behaviour in St. Lawrence River Greenland Sharks, Somniosus microcephalus. Can. Field Nat. 119, 355–358.
³ Gallant, J., C. Harvey-Clark, R.A. Myers, and M.J.W. Stokesbury. 2005. Sea lamprey (Petromyzon marinus) attached to a Greenland shark (Somniosus microcephalus) in the St. Lawrence Estuary, Canada. Northeastern Naturalist. 2006 13(1):35–38.
(ABOVE) Ocular parasitism observed by ORS in the St. Lawrence, such as in the preceding video, is below 5%. The eyes of most sharks show no sign of parasitic activity (past or present) (© ORS | Jeffrey Gallant). (BELOW) Sea lamprey (Petromyzon marinus) attached between the claspers of a male Greenland shark in the St. Lawrence Estuary (© ORS | Jeffrey Gallant).

TOXICITY

TOXICITY

Water and dissolved solutes, including various salts, calcium chloride and sulphates, pass through a fish’s body (cells, tissues, and organs) in a process known as osmosis. Larger molecules inside the blood and tissue fluids of fishes and sharks, including proteins and trimethylamine oxide (TMAO*), also exert a contributory osmotic effect but they are too large to pass through the channels that govern salt balance.

* By-product of the metabolic breakdown of proteins and amino acids.

If the salt concentration in a fish’s tissues is lower than that of the surrounding water, its body will absorb salt from the environment until both levels become equal. If a marine fish swims up a freshwater river, the reverse phenomenon will occur and it will diffuse salt into the environment via specialised sodium secreting cells located primarily in gill tissue. In both cases, too much or too little salt is detrimental to most fish species because they can only survive within a specific range of salt concentrations. Fish that are thus restricted to either freshwater or seawater are known as stenohaline. Some species, such as salmon, are able to osmoregulate in varying levels of salinity. These fish are called euryhaline.

When salt and other solutes enter a fish’s tissues, they force water out of the body. Since salt levels in marine fishes are lower than those of the surrounding environment, they must continually take in water and excrete salt through their gills. Salt levels in sharks are also lower than that of sea water but sharks manage osmosis differently. In order to maintain a stable amount of water in its body, the Greenland shark will retain a high concentration of urea in its blood, thus compensating for lower salt concentrations. However, because high levels of toxic urea will damage its body by destabilizing protein, the Greenland shark also retains even higher levels of trimethylamine oxide to counter the damaging effects of the urea. When the trimethylamine oxide and urea are combined with the salt in the shark’s tissues, the osmotic pressure of the shark’s body fluids is higher than that of the surrounding water. In other words, the shark is ‘saltier’ than seawater. Unlike bony fishes that must constantly take in water to replace water lost through osmosis, the Greenland shark does not need to expend energy to maintain life-sustaining water levels in its body.

In addition to contributing to the shark’s osmotic pressure, trimethylamine oxide and high levels of urea also serve as a natural antifreeze by stabilising the enzymes and proteins in the Greenland shark’s tissues. When the shark encounters extremely deep and cold conditions, this prevents the formation of ice crystals that disrupt cell walls and cause the leakage of cellular contents, which results in tissue and organ damage, then death.

When Greenland shark flesh is consumed, the digestive process turns trimethylamine oxide (TMAO) into trimethylamine (TMA), a substance that smells like ammonia and rotting fish. In addition to causing intestinal discomfort, trimethylamine also has adverse neurological effects akin to consuming excessive quantities of alcohol. Death may ensue in extreme cases when too much shark flesh has been consumed. Greenland shark flesh is nonetheless considered a delicacy in Iceland. See ‘Fisheries’ section below.

ATTACKS

ATTACKS

According to the Canadian Shark Attack Registry, the Greenland shark has been involved or suspected in four confirmed incidents with humans in Canada. As of 2023, most confrontations have involved stalking people by the shore, in boats or diving. None have resulted in an attack or injury.

It is important to note that the Greenland shark is found in water so deep and inhospitable to humans that most will never encounter a swimmer or diver during their entire lifetime. It would thus be very imprudent to label the shark as harmless to man based solely on the few existing statistics. During encounters by GEERG in the St. Lawrence Estuary, sharks have been observed leaving the bottom to investigate diver activities at the surface. In one instance, a shark stalked a team of divers all the way to the surface at the end of a dive. Both circumstances could be indicative of visual reconnaissance by an experienced live seal predator. Further demonstration of the shark’s ability to ambush live prey was experienced firsthand by GEERG researchers Harvey-Clark and Gallant during a frighteningly close encounter in zero visibility and shallow water (5 m, 15 ft) in June 2004.

Although the following are by no means attacks, thousands of victims of shipwrecks and war in the North Atlantic and the St. Lawrence—including the Empress of Ireland—may have been scavenged by the Greenland shark as it hovers just over the sea floor in search of food.

¹ Gallant, J. (2022. July 26)Canadian Shark Attack Registry (1st ed.). St. Lawrence Shark Observatory. https://geerg.ca/en/shark-attacks
Fallen Empress (Oil on canvas) © Jean-Louis Courteau. Courteau’s painting depicts how the Empress of Ireland may have appeared a few weeks after her sinking. Such a wide view of the wreck would in fact require extraordinary environmental conditions since visibility on the Empress of Ireland is usually poor, rarely exceeding six metres. The opportunistic Greenland shark homing in on the smell of death was likely a frequent visitor to the wreck in the months that followed the disaster.

FISHERIES

FISHERIES

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.

The shark’s flesh contains so much urea and TMAO (trimethylamine oxide) 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, putrefied shark meat is processed for human consumption by compressing it in a large perforated container—the meat is no longer buried in gravel for 6 to 12 weeks—to remove the toxic fluids, and then it is hung to dry outdoors for 2 to 4 months. It is then cut into bite-sized cubes, and served as an hors-d’oeuvre called hákarl or kæstur hákarl. Most of the hákarl produced in Iceland originates from the Bjarnahöfn Shark Museum, which uses by-catch sharks from Greenland.

The tasty treat is traditionally downed with a shot of Brennivín, the local firewater.

CORKSCREW CONTROVERSY

CORKSCREW CONTROVERSY

Sable Island (Nova Scotia) and now the North Sea (England & Scotland) are ripe with controversy surrounding the Greenland shark. It has long been suggested that Sable Island is a hunting ground for sharks based on the regular appearance of mutilated seal carcasses. Many of the victims present a corkscrew-like cut that twists around the length of the seal’s body. This particular wound is believed by many to be the result of a Greenland shark attack. Similar reports began to emanate out of the UK in the summer of 2010. After much analysis and debate, we do not believe that the Greenland shark is responsible for these so-called “corkscrew” kills. The environmental and behavioural evidence put forward simply does not concur with our own findings that are based in part on telemetry data and on firsthand observation of the Greenland shark underwater. Certain environmental conditions normally associated with the Greenland shark’s distribution also do not exist at either location.

Under certain conditions, seal carcasses that wash up dead on Sable Island without the distinctive corkscrew wound may still have been scavenged or killed by the Greenland shark. Mangled seal bodies are more typical of white shark predation, which certainly occur at Sable Island. The only confirmed bite wound pattern for the Greenland shark is circular. The Greenland shark bites into its victim and then twists itself repeatedly until a ‘plug’ of flesh is torn out. It may is possible for a large seal—or even a cetacean—to survive such an attack. The corkscrew wound simply does not fit with the known feeding pattern of the Greenland shark: a pattern that has been observed and filmed. The culprits are now believed to be seals themselves, as has been documented in Nova Scotia (1993)¹, Scotland (2016)², and during our second white shark expedition in the Magdalen Islands in 2023.

Gray seals (Halichoerus grypus) at Brion Island. The mangled base of the hind-flippers of the seal on the right shows a deep bite typical of a white shark (Carcharodon carcharias), which is known to be plentiful and active at this location. Photo © ORS | Jeffrey Gallant
Gray seal (Halichoerus grypus) cannibalism incident at Brion Island. Video still © ORS | Jeffrey Gallant | All Rights Reserved
¹ Bédard, C., Kovacs, K. and Hammill, M. (1993). Cannibalism by grey seals, Halichoerus grypus, on Amet Island, Nova Scotia. Marine Mammal Science, 9: 421-424. https://doi.org/10.1111/j.1748-7692.1993.tb00474.x
² Brownlow A, Onoufriou J, Bishop A, Davison N, Thompson D. (2016). Corkscrew Seals: Grey Seal (Halichoerus grypus) Infanticide and Cannibalism May Indicate the Cause of Spiral Lacerations in Seals. PLoS ONE 11(6): e0156464. doi:10.1371/journal.pone.0156464

RELATION WITH MAN

RELATION WITH MAN

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.

The Inuit long dried the Greenland shark’s skin to make boots and they used its teeth to cut hair. Sailors used its denticle-covered skin under their boots to prevent slipping on wet wooden decks.

To this day, 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. The St. Lawrence Shark Observatory aims to reverse this baseless and destructive trend with ground-breaking research and public-awareness.

DIVING WITH THE GREENLAND SHARK

DIVING WITH THE GREENLAND SHARK

As of 2019, there are very few known locations in the world where it is possible to dive with free-swimming Greenland sharks under natural conditions, i.e. when the shark is not baited or captured.

Diving with sharks that were caught on hook and line and then lassoed by the tail is by no means considered natural. This practice may in fact injure or even kill sharks.

Hundreds of natural encounters took place in Baie-Comeau, Québec, between 2003 and 2012. Other natural encounters have been reported in the Saguenay Fjord and in Qaanaaq, Greenland.

Diving with a Greenland shark in the St. Lawrence Estuary. Photo © ORS | Jeffrey Gallant

INUIT LEGENDS

INUIT LEGENDS

Skalugsuak

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

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 Mother of the Sea. Her fingers turned into various marine mammals, including the walrus, seals and the bowhead whale. Although not one of Sedna’s fingers, the Greenland shark remains close to Sedna. Because of its pungent smell, the shark is said to live in Sedna’s urine pot. It was also entrusted with the duty to avenge the goddess and one day, it capsized the father’s kayak while he was fishing and it ate him. When an Inuk dies in this fashion, it is said that the shark was sent by Sedna. In Pangnirtung, the Greenland shark is associated with the raven because it feeds on food scraps left behind by more formidable predators such as the orca (killer whale).

Arnakuagsak

Arnakuagsak

The Inuit goddess Arnakuagsak—Old Woman of the Sea—is the Greenlandic equivalent of the Canadian Inuit goddess Sedna. In Greenland, the shark is perceived as a helping spirit to shamans.

The Inuit goddess Arnakuagsak—Old Woman of the Sea—is the Greenlandic equivalent of the Canadian Inuit goddess Sedna. Statue of Arnakuagsak in Nuuk, Greenland. Photo © ORS | Jeffrey Gallant

HISTORICAL REFERENCES

HISTORICAL REFERENCES

We have found numerous documented references of Greenland sharks in the St. Lawrence and the Saguenay Fjord dating as far back as the early 1800’s.

In 1922, the crew of a Newfoundland sealer stuck in the ice captured over 30 Greenland sharks after attracting them to the surface by emptying the bilges of seal fat and blood. The sharks hauled out of the water with gaffes measured between 3.7 m and 4.9 m (12 ft to 16 ft). Many other stories tell of similar experiences.

When beluga whales were still hunted on the St. Lawrence, dozens of Greenland sharks were often drawn to the killing grounds at high tide where the whales were gutted and bled to death in towns such as Bergeronnes. As the tide went down, the sharks became beached on the shoals and they too were sliced open by the fishermen in order to extract their livers for oil. When the tide came up again, some sharks, still alive and much to the surprise of their executioners, managed to swim back to the ocean where they survived for a short while longer.

CONSERVATION STATUS

CONSERVATION STATUS

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

Read

In the North Atlantic, the white shark is seasonally present in all of the Maritime provinces, Newfoundland and Labrador, and Québec, including the St. Lawrence.

Shark and seal in New France
by Louis Nicolas circa 1690.

Meet the world's most maligned sea creature, the white shark.

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Recent headlines trumpeted the news that Canada has banned shark fins. Too good to be true? Well, it would appear the devil is in the detail…

Shark fins banned in Canada?
Not really.

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The Canadian Shark Attack Registry (CSAR) is the first database of all documented human encounters with sharks that have resulted in injury or death in Canada.

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In the North Atlantic, the white shark is seasonally present in all of the Maritime provinces, Newfoundland and Labrador, and Québec, including the St. Lawrence.

Shark and seal in New France
by Louis Nicolas circa 1690.

Meet the world's most maligned sea creature, the white shark.

Read

Misrepresented and misunderstood, sharks play a critical role in North Atlantic ecosystems, but they are under increasing threat due to their unfair reputation, pollution, and a lack of public awareness. Please donate to help us study and protect the sharks of the St. Lawrence and Atlantic Canada before it’s too late.Donations to ORS, an all-volunteer charitable not-for-profit organisation, are tax deductible in Canada. Canada Revenue Agency #834462913RR0001

DONATE

“Fear and indifference bite deeper than any shark.”— Jeffrey Gallant, St. Lawrence Shark ObservatoryTax deductible in Canada
CRA #834462913RR0001
DONATE
Misrepresented and misunderstood, sharks play a critical role in North Atlantic ecosystems, but they are under increasing threat due to their unfair reputation, pollution, and a lack of public awareness. Please donate to help us study and protect the sharks of the St. Lawrence and Atlantic Canada before it’s too late.Donations to ORS, an all-volunteer charitable not-for-profit organisation, are tax deductible in Canada. Canada Revenue Agency #834462913RR0001

DONATE

“Fear and indifference bite deeper than any shark.”— Jeffrey Gallant, St. Lawrence Shark ObservatoryTax deductible in Canada
CRA #834462913RR0001
DONATE