Greenland shark

Last updated

Greenland shark
Somniosus microcephalus okeanos.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Subdivision: Selachimorpha
Order: Squaliformes
Family: Somniosidae
Genus: Somniosus
Species:
S. microcephalus
Binomial name
Somniosus microcephalus
Somniosus microcephalus distmap.png
Range of the Greenland shark
Synonyms
  • Squalus squatina(non Linnaeus, 1758)
  • Squalus carcharis(Gunnerus, 1776)
  • Squalus microcephalusBloch & Schneider, 1801
  • Somniosus brevipinna(Lesueur, 1818)
  • Squalus borealis(Scoresby, 1820)
  • Squalus norvegianus(Blainville, 1825)
  • Scymnus gunneri(Thienemann, 1828)
  • Scymnus glacialis(Faber, 1829)
  • Scymnus micropterus(Valenciennes, 1832)
  • Leiodon echinatum(Wood, 1846)

The Greenland shark (Somniosus microcephalus), also known as the gurry shark or grey shark, is a large shark of the family Somniosidae ("sleeper sharks"), closely related to the Pacific and southern sleeper sharks. [2] Inhabiting the North Atlantic and Arctic Oceans, they are notable for their exceptional longevity, although they are poorly studied due to the depth and remoteness of their natural habitat.

Contents

Greenland sharks have the longest lifespan of any known vertebrate, estimated to be between 250 and 500 years. [3] They are among the largest extant species of shark, usually growing to between 2.4 and 7 m (7.9 and 23.0 ft) long and weighing between 400 and 1,400 kg (880 and 3,090 lb). They reach sexual maturity at about 150 years of age, and their pups are born alive after an estimated gestation period of 8 to 18 years. The shark is a generalist feeder, consuming a variety of available foods. [4]

Greenland shark meat is toxic to mammals due to its high levels of trimethylamine N-oxide, [5] although a treated form of it is eaten in Iceland as a delicacy known as kæstur hákarl . [6] Because they live deep in remote parts of the northern oceans, Greenland sharks are not considered a threat to humans, and no recorded attacks have ever occurred.

Description

The Greenland shark is likely one of the largest living species of shark. It usually grows to between 2.4 and 7 m (7.9 and 23.0 ft) long and weighs between 400 and 1,400 kg (880 and 3,090 lb). [7] [8] [9] [10] The all-tackle International Game Fish Association (IGFA) record for this species is 775 kg (1,709 lb). [11]

Greenland shark at Admiralty Inlet, Nunavut, with an Ommatokoita Greenland shark profile.jpg
Greenland shark at Admiralty Inlet, Nunavut, with an Ommatokoita

Males are typically smaller than females. It rivals the Pacific sleeper shark (possibly up to 7 m or 23 ft long) as the largest species in the family Somniosidae. The Greenland shark is a thickset species, with a short, rounded snout, small eyes, and very small dorsal and pectoral fins. The gill openings are very small for the species' great size.

Coloration can range from pale creamy-gray to blackish-brown and the body is typically uniform in color, though whitish spots or faint dark streaks are occasionally seen on the back. [9]

The shark is often infested by the copepod Ommatokoita elongata , a crustacean which attaches itself to the shark's eyes. [12] It was speculated that the copepod may display bioluminescence and thus attract prey for the shark in a mutualistic relationship, but this hypothesis has not been verified. [13] These parasites also damage the eyeball in several ways, leading to almost complete blindness. This does not seem to reduce the life expectancy or predatory ability of Greenland sharks, due to their strong reliance on smell and hearing. [12] [14]

Dentition

The dentition of a Greenland shark Britannica Shark Greenland Shark Dentition.png
The dentition of a Greenland shark

When feeding on large carcasses, the shark employs a rolling motion of its jaw. The 48 to 52 teeth of the upper jaw are very thin and pointed, lacking serrations. These upper jaw teeth act as an anchor while the lower jaw proceeds to cut massive chunks out of the prey.

The 48 to 52 lower teeth are interlocking, broad and square in shape, containing short, smooth cusps that point outward. [9] Teeth in the two halves of the lower jaw are strongly pitched in opposite directions. [15]

Behavior

Diet

The Greenland shark is an apex predator and eats primarily fish, although they have been observed actively hunting seals in Canada. [4] The prey found in the stomachs of Greenland sharks is an indicator of the active hunting patterns of these predators. [16] Recorded fish prey have included smaller sharks, skates, eels, herring, capelin, Arctic char, cod, rosefish, sculpins, lumpfish, wolffish, and flounder. [9] Small Greenland sharks eat predominantly squid, while the larger sharks that are greater than 200 cm (79 in) were discovered eating prey such as epibenthic and benthic fishes as well as seals. The largest of these sharks were found having eaten redfish, as well as other higher trophic level prey. [17]

It is proposed that, because of their slow speeds and low twitch speed muscle fiber, Greenland sharks hunt marine mammals such as seals and smaller cetaceans that are asleep, injured, or sick. Regarding most other benthic species, they utilize their cryptic coloration, and approach prey undetected before closing the remaining distance, expanding their buccal cavity to create suction, drawing in prey. This is the likely explanation for why the gut contents of Greenland sharks are often whole prey specimens. [16]

Greenland sharks have also been found with remains of moose [18] and reindeer (in one case an entire reindeer body) in their stomachs. [9] [19] The Greenland shark is known to be a scavenger and is attracted by the smell of rotting meat in the water. The sharks have frequently been observed gathering around fishing boats. [9] They also scavenge on seals. [20]

Although such a large shark could easily consume a human swimmer, the frigid waters it typically inhabits make the likelihood of attacks on people very low. No cases of predation on humans have been verified. [9]

Movement and migration

The shark occupies what tends to be a very deep environment seeking its preferred cold water (−0.6 to 12 °C or 31 to 54 °F) habitat. [1] As an ectotherm living in a just-above-freezing environment, the Greenland shark is sluggish and slow-moving, with the lowest swim speed and tail-beat frequency for its size across all fish species, which most likely correlates with its very slow metabolism and extreme longevity. [21] It swims at 1.22 km/h (0.76 mph), with its fastest cruising speed only reaching 2.6 km/h (1.6 mph). [22] Because this top speed is a fraction of that of a typical seal in their diet, biologists are uncertain how the sharks are able to prey on the seals. It is hypothesized that they may ambush them while they sleep. [23]

Greenland sharks migrate annually based on depth and temperature rather than distance, although some do travel. During the winter, the sharks congregate in the shallows (up to 80° north) for warmth but migrate separately in summer to the deeps or even farther south. The species has been observed at a depth of 2,200 metres (7,200 ft) by a submersible investigating the wreck of the SS Central America that lies about 160 nautical miles (180 mi; 300 km) east of Cape Hatteras, North Carolina. [24] Daily vertical migration between shallower and deeper waters has also been recorded. [25]

In August 2013, researchers from Florida State University caught a Greenland shark in the Gulf of Mexico at a depth of 1,749 m (5,738 ft), where the water temperature was 4.1 °C (39.4 °F). [26] Four previous records of Greenland shark were reported from Cuba and the northern Gulf of Mexico. [27] A more typical depth range is 0–1,500 m (0–4,900 ft), with the species often occurring in relatively shallow waters in the far north and deeper in the southern part of its range. [28] [29]

In April 2022, a large Somniosus shark was caught and subsequently released on Glover's Reef off the coast of Belize. This shark was identified as being either a Greenland shark or a Greenland/Pacific sleeper shark hybrid. This observation is notable for being the first possible record of a Greenland shark from the Western Caribbean, and being caught on a nearshore coral reef (the only other record of this species from the Caribbean was made from a deep-water habitat off the Caribbean coast of Colombia). The discovery indicates that Greenland sharks may have a wider distribution in the tropics, primarily at greater depths, than previously believed. [30]

When hoisted upon deck, it beats so violently with its tail, that it is dangerous to be near it, and the seamen generally dispatch it, without much loss of time. The pieces that are cut off exhibit a contraction of their muscular fibres for some time after life is extinct. It is, therefore, extremely difficult to kill, and unsafe to trust the hand within its mouth, even when the head is cut off. And, if we are to believe Crantz, this motion is to be observed three days after, if the part is trod on or struck.

— Henry William Dewhurst, The Natural History of the Order Cetacea (1834) [31]

Longevity

The Greenland shark has the longest known lifespan of all vertebrate species. [32] One Greenland shark was tagged off the coast of Greenland in 1936 and recaptured in 1952. Its measurements suggest that Greenland sharks grow at a rate of 0.5–1 cm (1⁄4–1⁄2 in) per year. [33] In 2016, a study based on 28 specimens that ranged from 81 to 502 cm (2 ft 8 in – 16 ft 6 in) in length used radiocarbon dating of crystals within the lenses of their eyes to determine their approximate ages. The oldest of the animals sampled, which was also the largest, had lived for 392 ± 120 years, and was consequently born between 1504 and 1744. [lower-alpha 1] The authors further concluded that the species reaches sexual maturity at about 150 years of age. [32] [34] [35] Efforts to conserve Greenland sharks are particularly important due to their extreme longevity, long maturation periods, and the heightened sensitivity of large shark populations. [36]

Reproduction

Greenland sharks are born alive (a process known as ovoviviparity) after an estimated gestation period of 8–18 years. [21] About ten pups per litter is normal, each initially measuring some 38–42 cm (15–16+1⁄2 in) in length. [34] [37] [ self-published source? ] Within a Greenland shark's uterus, villi serve a key function in supplying oxygen to embryos. It is speculated that due to embryonic metabolism dealing with reproduction, this only allows for a limited litter size of around 10 pups. [38] It has been estimated that due to their extreme longevity, Greenland sharks can have 200 to 700 pups during their lifetime. [21]

Physiological adaptations

Like other elasmobranchii, Greenland sharks have high concentrations of the two nitrogenous compounds urea and trimethylamine N-oxide (TMAO) in their tissues, which increase their buoyancy [39] and function as osmoprotectants. TMAO also counteracts the protein-destabilizing tendencies of urea [40] [41] and deep-water pressure. [42] [41] Its presence in the tissues of both elasmobranch and teleost fish has been found to increase with depth. [42] [43]

The blood of Greenland sharks contains three major types of hemoglobin, made up of two copies of α globin combined with two copies of three very similar β subunits. These three types show very similar oxygenation and carbonylation properties, which are unaffected by urea, an important compound in marine elasmobranchii physiology. They display identical electronic absorption and resonance in Raman spectroscopy, indicating that their heme-pocket structures are identical or highly similar. The hemoglobins also have a lower affinity for oxygen compared to temperate sharks. These characteristics are interpreted as adaptations to living at great water depths. [44]

As food

Greenland shark meat or kaestur hakarl in Iceland Hakarl near Bjarnahofn in Iceland.JPG
Greenland shark meat or kæstur hákarl in Iceland

The flesh of the Greenland shark is toxic because of the presence of high concentrations of trimethylamine oxide (TMAO). If the meat is eaten without pretreatment, the ingested TMAO is metabolized into trimethylamine, which may be a uremic toxin. Occasionally, sled dogs that eat the flesh are unable to stand up because of this effect. Similar toxic effects occur with the related Pacific sleeper shark, but not in most other shark species. [45] [46]

The meat can be treated for safe consumption by boiling in several changes of water, drying, or fermenting for several months to produce kæstur hákarl . Traditionally, this is done by burying the meat in boreal ground for 6–8 weeks, which presses the TMAO out of the meat and also results in partial fermentation. The meat is then excavated and hung in strips to dry for several more months. [47] It is considered a delicacy in Iceland. [48] [ self-published source? ] [49] [50]

Inuit legends

The Greenland shark's poisonous flesh has a high urea content, which gave rise to the Inuit legend of Skalugsuak, the first Greenland shark. [51] The legend says that an old woman washed her hair in urine (a common practice to kill head lice) and dried it with a cloth. The cloth blew into the ocean to become Skalugsuak. [52] Another legend tells of Sedna whose father cut off her fingers while drowning her, with each finger turning into a sea creature, including Skalugsuak. [53]

The Greenland shark plays a role in cosmologies of the Inuit from the Canadian Eastern Arctic and Greenland. Igloolik Inuit believe that the shark lives within the urine pot of Sedna, goddess of the sea, and consequently, its flesh has a urine-like smell and acts as a helping spirit to shamans. [54]

Ecological importance

Role in Arctic ecosystems

As both scavengers and active predators, Greenland sharks have established themselves as apex predators in Arctic ecosystems. They eat a wide variety of fish, seals, and other prey within these ecosystems and have an important role in the intricate food web. [16] [17]

Conservation and management

Greenland sharks are recognized as the longest-lived vertebrates on earth. They have a slow growth rate, late maturity period, and low fecundity, making the management and conservation of this species very important. As a result of their low productivity and extreme longevity, this species is particularly susceptible to overfishing. Therefore, Greenland sharks' longevity and conservative life history traits, in tandem with their vulnerability to accidental catching and commercial fishing, promotes a growing concern for the sustainability of this species. [55]

Threats

Overfishing and climate change are the main driving factors of Greenland shark diminishing numbers Arctic Jaws.jpg
Overfishing and climate change are the main driving factors of Greenland shark diminishing numbers

The shark has historically been hunted for its liver oil up until the development of synthetic oils and cessation of export of liver oil and skin from Greenland in the 1960s. [56] In the 1970s, the species was perceived as a problem for other fisheries in western Norway and the government subsidized a fishery to reduce the stock of the species. [57]

Approximately 3,500 individuals are taken each year in the Northwest Atlantic. Of this number, 89% comes from the Barents Sea, Iceland, Greenland, and the Canadian Arctic. [1]

The shark is likely affected by quantity, dynamics, and distribution of Arctic sea ice. [55] The rate of projected loss of sea ice will continue to negatively influence the abundance, distribution and availability of prey, while, at the same time, providing greater access for fishing fleets. [55] There is greater potential for new fisheries to develop as more productive and abundant southerly species invade the warming Arctic waters. [58]

See also

Notes

  1. ↑ Lower-age estimage 392 − 120 = 272 years, and 2016 − 272 = 1744; higher age estimate 392 + 120 = 512 years, and 2016 − 512 = 1504.

Related Research Articles

<span class="mw-page-title-main">Shark</span> Infraclass of predatory cartilaginous fish

Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha and are the sister group to the Batoidea. Some sources extend the term "shark" as an informal category including extinct members of Chondrichthyes with a shark-like morphology, such as hybodonts. Shark-like chondrichthyans such as Cladoselache and Doliodus first appeared in the Devonian Period, though some fossilized chondrichthyan-like scales are as old as the Late Ordovician. The oldest confirmed modern sharks (selachimorphs) are known from the Early Jurassic, about 200 million years ago, though records of true sharks may extend back as far as the Permian.

<span class="mw-page-title-main">Narwhal</span> Medium-sized toothed whale species

The narwhal, is a species of toothed whale, and the only member of the genus Monodon. Its closest living relative is the beluga whale, and cases of interbreeding between the two species has been recorded. It is sexually dimorphic, as adult males are larger than females and have a long single tusk that can be up to 3 m (9.8 ft). The narwhal has a mottled pigmentation, with blackish-brown markings over a white background. Instead of a dorsal fin, the narwhal possesses a shallow dorsal ridge which is thought to facilitate movement under the ice, or reduce surface area, and so heat loss. An adult narwhal is typically 3.0 to 5.5 m in length and 800 to 1,600 kg in weight. Carl Linnaeus scientifically described the species in his 1758 work Systema Naturae.

<span class="mw-page-title-main">Tiger shark</span> Species of ground shark

The tiger shark is a species of ground shark, and the only extant member of the genus Galeocerdo and family Galeocerdonidae. It is a large macropredator, with females capable of attaining a length of over 5 m. Populations are found in many tropical and temperate waters, especially around central Pacific islands. Its name derives from the dark stripes down its body, which resemble a tiger's pattern, but fade as the shark matures.

<span class="mw-page-title-main">Squaliformes</span> Order of fishes

The Squaliformes are an order of sharks that includes about 126 species in seven families.

<span class="mw-page-title-main">Bull shark</span> Species of fish

The bull shark, also known as the Zambezi shark in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in rivers. It is known for its aggressive nature, and presence mainly in warm, shallow brackish and freshwater systems including estuaries and (usually) lower reaches of rivers. This aggressive nature is a reason for its population being listed as vulnerable on the IUCN Red List. Shark-culling occurs near beaches to protect beachgoers, which is one of the causes of bull shark populations continuing to decrease.

<i>Arctogadus</i> Genus of fishes

Arctogadus glacialis, known also with ambiguous common names Arctic cod and polar cod, is an Arctic species of fish in the cod family Gadidae, related to the true cod. Arctogadus glacialis is found in icy water. They grow to about 30 cm long, and are favorite food of narwhals and other arctic whales.

<span class="mw-page-title-main">Pacific sleeper shark</span> Species of shark

The Pacific sleeper shark is a sleeper shark of the family Somniosidae, found in the North Pacific on continental shelves and slopes in Arctic and temperate waters between latitudes 70°N and 22°N and in at least two places in the western tropical Pacific near Palau and the Solomon Islands, from the surface to 2,000 metres (6,600 ft) deep. The first evidence of the sharks in the western tropical Pacific emerged from a National Geographic video taken near the Solomon Islands in 2015. Its length is up to 4.4 m (14 ft), although it could possibly reach lengths in excess of 7 m (23 ft).

<span class="mw-page-title-main">Elasmobranchii</span> Subclass of fishes

Elasmobranchii is a subclass of Chondrichthyes or cartilaginous fish, including modern sharks, rays, skates, and sawfish. Members of this subclass are characterised by having five to seven pairs of gill clefts opening individually to the exterior, rigid dorsal fins and small placoid scales on the skin. The teeth are in several series; the upper jaw is not fused to the cranium, and the lower jaw is articulated with the upper. The details of this jaw anatomy vary between species, and help distinguish the different elasmobranch clades. The pelvic fins in males are modified to create claspers for the transfer of sperm. There is no swim bladder; instead, these fish maintain buoyancy with large livers rich in oil.

<span class="mw-page-title-main">Hákarl</span> National dish of Iceland consisting of fermented shark

Hákarl, referred to as fermented shark in English, is a national dish of Iceland consisting of Greenland shark or other sleeper shark that has been cured with a particular fermentation process and hung to dry for four to five months. It has a strong ammonia-rich smell and fishy taste, making hákarl an acquired taste.

<span class="mw-page-title-main">Somniosidae</span> Family of sharks

The Somniosidae are a family of sharks in the order Squaliformes, commonly known as sleeper sharks. The common name "sleeper shark" comes from their slow swimming, low activity level, and perceived non-aggressive nature.

<i>Somniosus</i> Genus of sharks

Somniosus is a widely distributed genus of deepwater dogfish sharks in the family Somniosidae. Several members of the genus are believed to attain lengths up to 7 m (23 ft), thus ranking among the largest of sharks.

Trimethylamine <i>N</i>-oxide Chemical compound

Trimethylamine N-oxide (TMAO) is an organic compound with the formula (CH3)3NO. It is in the class of amine oxides. Although the anhydrous compound is known, trimethylamine N-oxide is usually encountered as the dihydrate. Both the anhydrous and hydrated materials are white, water-soluble solids.

<span class="mw-page-title-main">Southern sleeper shark</span> Species of shark

The southern sleeper shark, or Whitley's sleeper shark, is a deepwater benthopelagic sleeper shark of the family Somniosidae found in the southern and subantarctic extremes of the Atlantic, Indian and Pacific Oceans, and some northern reaches of the Antarctic oceans. It has been recorded near the southernmost areas of South America, near South Africa, southern Australia, Tasmania and New Zealand, as well as more remote locations in the south-central Indian Ocean.

Trimethylamine N-oxide reductase is a microbial enzyme that can reduce trimethylamine N-oxide (TMAO) into trimethylamine (TMA), as part of the electron transport chain. The enzyme has been purified from E. coli and the photosynthetic bacteria Roseobacter denitrificans.

<span class="mw-page-title-main">Marine vertebrate</span> Marine animals with a vertebrate column

Marine vertebrates are vertebrates that live in marine environments. These are the marine fish and the marine tetrapods. Vertebrates are a subphylum of chordates that have a vertebral column (backbone). The vertebral column provides the central support structure for an internal skeleton. The internal skeleton gives shape, support, and protection to the body and can provide a means of anchoring fins or limbs to the body. The vertebral column also serves to house and protect the spinal cord that lies within the column.

<span class="mw-page-title-main">Diversity of fish</span> Fish species categorized by various characteristics

Fish are very diverse animals and can be categorised in many ways. Although most fish species have probably been discovered and described, about 250 new ones are still discovered every year. According to FishBase about 34,800 species of fish had been described as of February 2022, which is more than the combined total of all other vertebrate species: mammals, amphibians, reptiles and birds.

<i>Ommatokoita</i> Genus of crustaceans

Ommatokoita is a monotypic genus of copepods, the sole species being Ommatokoita elongata. However, a specimen has been found on the skin of Etmopterus princeps, which has been assigned to the genus but not the species.

<i>Aega psora</i> Species of crustacean

Aega psora is a species of isopod crustacean that parasitises a number of fish species in the North Atlantic. It is a serious ectoparasite of larger species of fish, particularly when they are injured.

<span class="mw-page-title-main">Planktivore</span> Aquatic organism that feeds on planktonic food

A planktivore is an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton. Planktivorous organisms encompass a range of some of the planet's smallest to largest multicellular animals in both the present day and in the past billion years; basking sharks and copepods are just two examples of giant and microscopic organisms that feed upon plankton.

<span class="mw-page-title-main">Bomb pulse</span> Sudden increase of carbon-14 in the Earths atmosphere due to nuclear bomb tests

The bomb pulse is the sudden increase of carbon-14 (14C) in the Earth's atmosphere due to the hundreds of aboveground nuclear bombs tests that started in 1945 and intensified after 1950 until 1963, when the Limited Test Ban Treaty was signed by the United States, the Soviet Union and the United Kingdom. These hundreds of blasts were followed by a doubling of the relative concentration of 14C in the atmosphere. The reason for the term “relative concentration”, is because the measurements of 14C levels by mass spectrometers are most accurately made by comparison to another carbon isotope, often the common isotope 12C. Isotope abundance ratios are not only more easily measured, they are what 14C carbon daters want, since it is the fraction of carbon in a sample that is 14C, not the absolute concentration, that is of interest in dating measurements. The figure shows how the fraction of carbon in the atmosphere that is 14C, of order only a part per trillion, has changed over the past several decades following the bomb tests. Because 12C concentration has increased by about 30% over the past fifty years, the fact that “pMC”, measuring the isotope ratio, has returned (almost) to its 1955 value, means that 14C concentration in the atmosphere remains some 30% higher than it once was. Carbon-14, the radioisotope of carbon, is naturally developed in trace amounts in the atmosphere and it can be detected in all living organisms. Carbon of all types is continually used to form the molecules of the cells of organisms. Doubling of the concentration of 14C in the atmosphere is reflected in the tissues and cells of all organisms that lived around the period of nuclear testing. This property has many applications in the fields of biology and forensics.

References

  1. 1 2 3 Kulka, D.W.; Cotton, C.F.; Anderson, B.; Derrick, D.; Herman, K.; Dulvy, N.K. (2020). "Somniosus microcephalus". IUCN Red List of Threatened Species . 2020: e.T60213A124452872. doi: 10.2305/IUCN.UK.2020-3.RLTS.T60213A124452872.en . Retrieved 19 November 2021.
  2. ↑ Yano, Kazunari; Stevens, John D.; Compagno, Leonard J.V. (2004). "A review of the systematics of the sleeper shark genus Somniosus with redescriptions of Somniosus (Somniosus) antarcticus and Somniosus (Rhinoscymnus) longus (Squaliformes: Somniosidae)". Ichthyological Research. 51 (4): 360–373. Bibcode:2004IchtR..51..360Y. doi:10.1007/s10228-004-0244-4. S2CID   38054192.
  3. ↑ "How long do Greenland sharks live?". National Ocean Service. Retrieved 2 June 2021.
  4. 1 2 Nielsen, Julius; Hedeholm, Rasmus B.; Simon, Malene; Steffensen, John F. (1 January 2014). "Distribution and feeding ecology of the Greenland shark (Somniosus microcephalus) in Greenland waters". Polar Biology. 37 (1): 37–46. Bibcode:2014PoBio..37...37N. doi:10.1007/s00300-013-1408-3. ISSN   1432-2056. S2CID   17829168.
  5. ↑ Anthoni, Uffe; Christophersen, Carsten; Gram, Lone; Nielsen, Niels H.; Nielsen, Per (1991). "Poisonings from flesh of the Greenland shark Somniosus microcephalus may be due to trimethylamine". Toxicon. 29 (10): 1205–1212. doi:10.1016/0041-0101(91)90193-U. PMID   1801314.
  6. ↑ Durst, Sidra (2012). "Hákarl". In Deutsch, Jonathan; Murakhver, Natalya (eds.). They Eat That? A cultural encyclopedia of weird and exotic food from around the world. Bloomsbury Publishing USA. pp. 91–92. ISBN   978-0-313-38059-4.
  7. ↑ Mills, Patrick (2006). Dewey, Tanya (ed.). "Somniosus microcephalus". Animal Diversity Web. University of Michigan.
  8. ↑ McClain, Craig R.; Balk, Meghan A.; Benfield, Mark C.; Branch, Trevor A.; Chen, Catherine; Cosgrove, James; et al. (13 January 2015). "Sizing ocean giants: patterns of intraspecific size variation in marine megafauna". PeerJ. 3: e715. doi: 10.7717/peerj.715 . PMC   4304853 . PMID   25649000.
  9. 1 2 3 4 5 6 7 Eagle, Dane. "Greenland shark". Florida Museum of Natural History. Archived from the original on 21 March 2013. Retrieved 26 June 2012.
  10. ↑ Wood, Gerald (1983). The Guinness Book of Animal Facts and Feats . Guinness Superlatives. ISBN   978-0-85112-235-9.[ page needed ]
  11. ↑ "IGFA Member Services". igfa.org.
  12. 1 2 Borucinska, J.D.; Benz, G.W.; Whiteley, H.E. (1998). "Ocular lesions associated with attachment of the parasitic copepod Ommatokoita elongata (Grant) to corneas of Greenland sharks, Somniosus microcephalus(Bloch & Schneider)". Journal of Fish Diseases. 21 (6): 415–422. doi: 10.1046/j.1365-2761.1998.00122.x .
  13. ↑ Berland, Bjørn (1961). "Copepod Ommatokoita elongata(Grant) in the eyes of the Greenland shark – a possible cause of mutual dependence". Nature. 191 (4790): 829–830. Bibcode:1961Natur.191..829B. doi:10.1038/191829a0. S2CID   4262630.
  14. ↑ Ferrando, S.; Gallus, L.; Ghigliotti, L.; Vacchi, M.; Nielsen, J.; Christiansen, J.S.; Pisano, E. (1 August 2016). "Gross morphology and histology of the olfactory organ of the Greenland shark Somniosus microcephalus". Polar Biology. 39 (8): 1399–1409. Bibcode:2016PoBio..39.1399F. doi:10.1007/s00300-015-1862-1. ISSN   1432-2056. S2CID   17368573.
  15. ↑ "Greenland Shark". Marinebiodiversity.ca. Centre for Marine Biodiversity. Archived from the original on 3 April 2014. Retrieved 23 May 2011.
  16. 1 2 3 Lydersen, Christian; Fisk, Aaron T.; Kovacs, Kit M. (November 2016). "A review of Greenland shark (Somniosus microcephalus) studies in the Kongsfjorden area, Svalbard Norway". Polar Biology. 39 (11): 2169–2178. Bibcode:2016PoBio..39.2169L. doi:10.1007/s00300-016-1949-3. ISSN   0722-4060. S2CID   15050012.
  17. 1 2 Nielsen, Julius; Christiansen, Jørgen Schou; Grønkjær, Peter; Bushnell, Peter; Steffensen, John Fleng; Kiilerich, Helene Overgaard; et al. (2019). "Greenland shark (Somniosus microcephalus) stomach contents and stable isotope values reveal an ontogenetic dietary shift". Frontiers in Marine Science. 6. doi: 10.3389/fmars.2019.00125 . hdl: 10037/15917 . ISSN   2296-7745.
  18. ↑ "Moose-eating shark rescued in Newfoundland harbour". CBC News. 21 November 2013. Retrieved 21 November 2013.
  19. ↑ Howden, Daniel (12 August 2008). "Clash of the fiercest predators as shark eats polar bear". The Independent . Retrieved 26 June 2012.
  20. ↑ Yong, Ed (11 August 2016). "The sharks that live to 400". The Atlantic . Retrieved 15 August 2016.
  21. 1 2 3 Augustine, Starrlight; Lika, Konstadia; Kooijman, Sebastiaan A.L.M. (1 December 2017). "Comment on the ecophysiology of the Greenland shark, Somniosus microcephalus" (PDF). Polar Biology. 40 (12): 2429–2433. Bibcode:2017PoBio..40.2429A. doi:10.1007/s00300-017-2154-8. hdl: 1871.1/a6f1d885-5cd1-431f-8e85-540060915b6c . ISSN   1432-2056. S2CID   20852421.
  22. ↑ Watanabe, Yuuki Y.; Lydersen, Christian; Fisk, Aaron T.; Kovacs, Kit 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. doi:10.1016/j.jembe.2012.04.021.
  23. ↑ Scales, Helen (June 2012). "Slow sharks sneak up on sleeping seals (and eat them)?". National Geographic News. Archived from the original on 28 June 2012. Retrieved 28 December 2012.
  24. ↑ "America's lost treasure". sscentralamerica.com. Archived from the original on 24 November 2016. Retrieved 14 February 2017.
  25. ↑ Owen, D. (2009). Shark: In peril in the sea. Allen & Unwin.
  26. ↑ Grubs, Dean (15 August 2013). " Deep-C Scientists Capture First Greenland Shark in the Gulf of Mexico". deep-c.org
  27. ↑ Benfield, Mark (2008). "The second report of a sleeper shark (Somniosus (Somniosus) sp.) from the bathypelagic waters of the northern Gulf of Mexico". Bulletin of Marine Science. 82 (2): 195–198.
  28. ↑ Yano, K.; Stevens, J.D.; Compagno, L.J.V. (2007). "Distribution, reproduction and feeding of the Greenland shark Somniosus (Somniosus) microcephalus, with notes on two other sleeper sharks, Somniosus (Somniosus) pacificus and Somniosus (Somniosus) antarcticus". Journal of Fish Biology. 70 (2): 374–390. Bibcode:2007JFBio..70..374Y. doi:10.1111/j.1095-8649.2007.01308.x.
  29. ↑ Møller, P.R.; Nielsen, J.; Knudsen, S.W.; Poulsen, J.Y.; Sünksen, K.; Jørgensen, O.A. (2010). "A checklist of the fish fauna of Greenland waters". Zootaxa. 2378 (1): 1–84.
  30. ↑ Kasana, Devanshi; Martinez, Hector Daniel; Faux, Omar; Monzon, Neri; Guerra, Elio; Chapman, Demian D. (2022). "First report of a sleeper shark (Somniosus sp.) in the western Caribbean, off the insular slope of a coral atoll". Marine Biology. 169 (8): 101. Bibcode:2022MarBi.169..101K. doi:10.1007/s00227-022-04090-3. S2CID   250590599 . Retrieved 30 July 2022.
  31. ↑ Dewhurst, H.W. (1834). The Natural History of the Order Cetacea and the Oceanic Inhabitants of the Arctic Regions. Verf. Illustrated with numerous lithographic and wood engravings
  32. 1 2 Nielsen, Julius; Hedeholm, Rasmus B.; Heinemeier, Jan; Bushnell, Peter G.; Christiansen, Jørgen S.; Olsen, Jesper; et al. (2016). "Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus)". Science. 353 (6300): 702–704. Bibcode:2016Sci...353..702N. doi:10.1126/science.aaf1703. hdl: 2022/26597 . PMID   27516602. S2CID   206647043.
    de Lazaro, Enrico (12 August 2016). "Greenland sharks are longest-lived vertebrates on Earth, marine biologists say". Science News.
  33. ↑ Caloyianis, Nick (September 1998). "Greenland Sharks". National Geographic. 194 (3): 60–71.
  34. 1 2 Pennisi, Elizabeth (11 August 2016). "Greenland shark may live 400 years, smashing longevity record". Science. doi:10.1126/science.aag0748.
  35. ↑ O'Connor, M.R. (25 November 2017). "The strange and gruesome story of the Greenland shark, the longest-living vertebrate on Earth". The New Yorker . Retrieved 27 November 2017.
  36. ↑ Davis, Brendal; van der Zwaag, David L.; Cosandey-Godin, Aurelie; Hussey, Nigel E.; Kessel, Steven T.; Worm, Boris (1 October 2013). "The conservation of the Greenland shark (Somniosus microcephalus): Setting scientific, law, and policy coordinates for avoiding a species at risk". Journal of International Wildlife Law & Policy. 16 (4): 300–330. doi:10.1080/13880292.2013.805073. ISSN   1388-0292. S2CID   84039070.
  37. ↑ Martin, R. Aidan. "Greenland shark". elasmo-research.org. Retrieved 23 May 2011.
  38. ↑ Carter, Anthony M.; Soma, Hiroaki (1 August 2020). "Viviparity in the longest-living vertebrate, the Greenland shark (Somniosus microcephalus)". Placenta. 97: 26–28. doi:10.1016/j.placenta.2020.05.014. PMID   32792058. S2CID   221121663.
  39. ↑ Withers, Philip C.; Morrison, Garrick; Guppy, Michael (1994). "Buoyancy Role of Urea and TMAO in an Elasmobranch Fish, the Port Jackson Shark, Heterodontus portusjacksoni". Physiological Zoology. 67 (3): 693–705. doi:10.1086/physzool.67.3.30163765. JSTOR   30163765. S2CID   100989392.
  40. ↑ Bennion, Brian J.; Daggett, Valerie (2004). "Counteraction of urea-induced protein denaturation by trimethylamine N-oxide: a chemical chaperone at atomic resolution". Proceedings of the National Academy of Sciences of the United States of America. 101 (17): 6433–6438. Bibcode:2004PNAS..101.6433B. doi: 10.1073/pnas.0308633101 . PMC   404062 . PMID   15096583.
  41. 1 2 Yancey, Paul H. (2005). "Organic osmolytes as compatible, metabolic and counteracting cytoprotectants in high osmolarity and other stresses". The Journal of Experimental Biology. 208 (pt 15): 2819–2830. doi: 10.1242/jeb.01730 . PMID   16043587.
  42. 1 2 Yancey, Paul H.; Gerringer, Mackenzie E.; Drazen, Jeffrey C.; Rowden, Ashley A.; Jamieson, Alan (2014). "Marine fish may be biochemically constrained from inhabiting the deepest ocean depths". Proceedings of the National Academy of Sciences of the United States of America. 111 (12): 4461–4465. Bibcode:2014PNAS..111.4461Y. doi: 10.1073/pnas.1322003111 . PMC   3970477 . PMID   24591588.
  43. ↑ Treberg, Jason R.; Driedzic, William R. (2002). "Elevated levels of trimethylamine oxide in deep-sea fish: Evidence for synthesis and intertissue physiological importance". Journal of Experimental Zoology. 293 (1): 39–45. Bibcode:2002JEZ...293...39T. doi:10.1002/jez.10109. PMID   12115917.
  44. ↑ Russo, Roberta; Giordano, Daniela; Paredi, Gianluca; Marchesani, Francesco; Milazzo, Lisa; Altomonte, Giovanna; et al. (12 October 2017). "The Greenland shark Somniosus microcephalus — hemoglobins and ligand-binding properties". PLOS ONE. 12 (10): e0186181. Bibcode:2017PLoSO..1286181R. doi: 10.1371/journal.pone.0186181 . PMC   5638460 . PMID   29023598.
  45. ↑ "The Greenland shark is a very odd species of shark". Shark Sider. December 2014. Retrieved 17 August 2016.
  46. ↑ "The Greenland shark: An icy mystery". Sharkopedia. Discovery.com. Archived from the original on 7 January 2018. Retrieved 17 August 2016.
  47. ↑ Wheatley, Gale (20 September 2010). "Iceland's wild culinary traditions: Hákarl and brennivín". gourmetwonderland.com. Archived from the original on 6 March 2014. Retrieved 12 August 2016.
  48. ↑ Blumenfeld, Jenna (16 June 2011). "My encounter with hákarl, the worst tasting food on Earth". theexpeditioner.com. Archived from the original on 8 July 2015. Retrieved 7 July 2015.
  49. ↑ "Hákarl – Icelandic fermented shark". Islands. Retrieved 13 August 2016.[ permanent dead link ]
  50. ↑ Shardlow, Ju; Romeo, Claudia. "Greenland shark is the most toxic shark in the world, but one family has been curing it for hundreds of years". Insider. Retrieved 23 January 2022.
  51. ↑ O'Reilly, Lindsay (2004). "Skalugsuak's origins". Canadian Geographic. Archived from the original on 21 March 2016. Retrieved 13 August 2016.
  52. ↑ "Greenland shark". Greenland Shark and Elasmobranch Education and Research Group. Archived from the original on 14 October 2013. Retrieved 13 August 2016.
  53. ↑ Helfman, Gene; Burgess, George H. (2014). Sharks: The animal answer guide. Johns Hopkins University Press.
  54. ↑ Idrobo, Carlos Julián (February 2009). The Pangnirtung Inuit and the Greenland Shark (PDF) (M.Sc. thesis). University of Manitoba. p. 66. OCLC   855389661.
  55. 1 2 3 Edwards, Jena E.; Hiltz, Elizabeth; Broell, Franziska; Bushnell, Peter G.; Campana, Steven E.; Christiansen, Jørgen S.; et al. (2 April 2019). "Advancing research for the management of long-lived species: A case study on the Greenland shark". Frontiers in Marine Science. 6: 87. doi: 10.3389/fmars.2019.00087 . hdl: 10037/16245 . ISSN   2296-7745.
  56. ↑ Hedeholm, R., Nygaard, R. and Nogueira, A. 2018. Greenland shark in Greenland waters in NAFO Subarea 1 and ICES XIV. North Atlantic Fisheries Organization Scientific Committee Report 18/037: 1-10.
  57. ↑ Castro, José I.; Woodley, Christa M.; Brudek, Rebecca L. (1999). "4. The status of elasmobranch species". A preliminary evaluation of the status of shark species. FAO fisheries technical paper. Rome: FAO. ISBN   978-92-5-104299-1.
  58. ↑ Tai, Travis C.; Steiner, Nadja S.; Hoover, Carie; Cheung, William W.L.; Sumaila, U. Rashid (2019). "Evaluating present and future potential of arctic fisheries in Canada". Marine Policy. 108: 103637. doi:10.1016/j.marpol.2019.103637.

Further reading

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.