Norwegian shark. Life of the Greenland Shark

The polar shark is a cartilaginous fish that science has not studied very well. There is very little official information about this species.

This is due to the fact that polar sharks live in harsh waters, and at considerable depths.

These predators are found in the White Sea, in the southern waters of the Pechersk and Barents seas. Some individuals migrate further east and end up in the Kara Sea. Arctic sharks are often found off the coast of Greenland, Norway and Iceland. In addition, representatives of the species live in the Hudson Strait and the Baffin Sea.

Shark appearance

These cartilaginous fish are almost as large in size as white fish. The body length of the polar shark varies between 6.5-7 meters.

Individuals weigh about a ton, but there are specimens whose weight reaches 2 tons. Average length The polar shark is 3-4 meters long and has an average weight of 800 kilograms.

If we talk about aggressiveness, then these sharks are significantly inferior to their counterparts. The polar shark's body has a perfectly streamlined shape, reminiscent of a torpedo.

The color can be brown or dark green. The entire body is covered with small black-violet spots. The head, in comparison with the size of the whole body, is not large. The jaws are wide. The teeth on the upper and lower jaws are different. In the upper jaw they are sharp and sparse, and in the lower jaw they are blunt square shape and are planted much denser. The caudal fin has an asymmetrical shape: it top part much larger than the bottom.

Shark behavior and nutrition

In summer, these predators prefer to stay at great depths - approximately 500-1000 meters. At this depth, sharks hunt invertebrates and fish. In addition, the diet includes carrion: corpses, .

There have been no recorded cases of polar sharks attacking large mammals. These predators are too slow, and also cowardly, so they do not fight with tougher and stronger animals. Also, in history there are no recorded cases of polar shark attacks on people.

IN winter time these predatory fish rise from the depths to the upper layers of water. At the same time, the predator’s diet remains unchanged. During this period, polar sharks become available for fishing.

Reproduction and lifespan

The breeding season occurs in spring. Arctic sharks lay several hundred eggs in the depths. The eggs are quite large, their length is approximately 8 centimeters, they have an oval shape. Eggs do not have a protective cornea.

The lifespan of polar sharks is approximately 400-500 years, with females living on average 10 years longer than males.

Enemies of the polar shark

The most basic and, probably, the only enemy of the polar shark is man. This fish has a very large liver, and it is because of the liver that these fish are caught. Technical fat is made from it. The meat of polar sharks is poisonous. This is because they do not have a bladder or urinary tract, and all body waste is excreted through the skin.

The polar shark is classified as a cartilaginous fish, which science has not yet studied well enough. Almost no official information is provided about this species.

Studying the Greenland shark is difficult because it lives in icy waters and at great depths.

You can meet the Greenland polar shark in the Pechersk and Barents seas. Some sharks move even further east and end up in the Kara Sea. The polar shark can also be found near the Icelandic, Norwegian and Greenlandic coasts. This species of shark lives in both the Hudson Strait and the Baffin Sea.

Appearance

In appearance it resembles a torpedo. It has small fins on its back, which have become its unique feature. It is this type of shark that lives longer than others - about 200 years! And some scientists believe that their age may be 500 years.

The Greenland polar shark is a long-liver, since the development of all vital processes in its body is very slow. And it grows also slowly. One of the sharks was observed for 15 years in one of the scientific institutes. During all this time, she grew only 8 centimeters.

The Greenland shark is impressive with its huge size and slowness. It moves at a very low speed - less than 1 km per hour. This can be explained by the fact that it lives in quite cold water, And a large number of The shark has to spend energy on warming its own body.

It weighs almost a ton, but there are individuals whose weight is two tons. The body length of the animal is on average four meters, sometimes reaching six, and the average weight is about eight hundred kg.

1. Color of the skin. Usually brown or dark green in color. There are small black and purple spots all over the body.
2. Head small in relation to the body.
3. Her jaws are wide. Both jaws have different teeth. On the upper part the teeth are sharp, needle-shaped, there are not many of them. And on the lower jaw they are square in shape and there are much more of them, they are very curved. The predator's mouth is small and cannot open much.
4. The caudal fin is asymmetrical: The top side is much larger than the bottom.

Natural predator antifreeze

How does the Greenland shark manage to survive in icy water? She does this thanks to the absence of kidneys and a urinary system - ammonia and urine are excreted through the skin of the animal.

For this reason, the tissues of the predator’s muscles contain a huge amount of trimethyl nitrogen, which warms the shark’s body even at sub-zero temperatures.

Trimethylamine, which is present in Greenland shark meat, causes dogs that have eaten this meat to become intoxicated - dogs cannot for a long time rise.

The Eskimos have their own nickname for people under the influence of alcohol - “sick shark”, because a person becomes as slow as the predator itself.

Predator behavior and food

The Greenland shark does not leave the Arctic waters. IN summer time it is located at a depth of up to two thousand meters, and in winter it floats on the surface, since temperature regime The water in this place is higher than at depth. It feeds on a variety of living creatures from fish to pinnipeds, and sometimes attacks animals that inadvertently find themselves in the water.

For a very long time it was believed that it feeds only on carrion due to its slowness. For this reason, it is called “sleepy”, because at such speed there is no way to chase prey!

In 2008, ichthyologist K. Kovacs discovered the remains of a dead shark in the stomach polar bear, which she ate alive. This news has become the subject of a long-running dispute among scientists - can a Greenland shark attack and eat a polar bear?

In theory, this is possible; she will have enough strength, since her body weight and length are 2 times greater than that of a polar bear.

But scientists Vince Gallucci and Jeffrey Galanta argue that the polar shark will not take an unjustified risk - attacking a predator that has powerful fangs and claws. She will be able to suffice with much smaller prey, the hunting of which requires less energy expenditure and risk to life.

Gallucci believes that the bear could have drowned on its own, and the predator simply found it and ate it. However, if you pay attention to another fact, the legends of the people of Greenland - the Inuit Eskimos - make it possible that a Greenland shark can attack a polar bear. Their folklore contains stories about these predators. They talk about attacks by predators on boats and animals that were careless enough to get close to the water.

This species ranks 5th among other predators, but in terms of aggression it is not far from the whale shark.

Reproduction and lifespan

Polar sharks begin to reproduce with the arrival of spring. At great depths they lay about 500 eggs:

• the eggs are very large in size, their length reaches eight centimeters;
• have an oval shape;
• they lack the protective cornea.

There is also an assumption that the Greenland polar shark immediately gives birth to small sharks, usually about ten pieces.

Duration life of this species can be 55 years, and sometimes more, reaching 200 years. Females live much longer than males.

Enemies of this predator

The main, and, most likely, only enemy of this animal is man. This species has a very large liver, which is actually why the predator is caught. The organ is needed for the production of technical fat. Animal meat is poisonous due to the fact that all waste comes out through the surface of the skin.

The local people, who constantly catch the predator, have learned to eat its meat. First the meat is soaked, then boil several times in new water, and only after that it becomes suitable for consumption. Uncooked meat has a bad taste and a pronounced alcoholic effect.

The ancient Vikings created very interesting way preparing this meat: they separated it from the bone, buried it and left it there for a month. Then they dug it out, aired it and dried it until the surface of the meat was covered with a crust. After this, cuts were made from all the meat and only the inner part remained yellow color. This unique dish is called haukarl and can be enjoyed in Iceland during the Terrablot festival.

In general, there is not much demand for the meat of this predator, so if it is accidentally caught in fishing nets, it is released back into the cold Arctic waters.

Fascinating facts

As is already known, thanks to a huge number of different studies, this species of shark is the oldest vertebrate in the whole world. But scientists have tried very hard to establish this fact. The whole point is that most of the ways, which are used to determine the age of animals, cannot be used with this species. It does not have layers of calcium carbonate in its ears, which is used to determine the age of many fish. The predator's vertebrae are very soft, and this makes it impossible to determine life expectancy by the growth of the vertebral rings.

The age of the Greenland shark was found out only thanks to the protein in the lens of the eye. It's evolving I've been a predator all my life, and this protein appears during embryonic development.

Despite their impressive lifespan, much about the life of Arctic sharks remains a mystery to this day.

Scientists have caught a shark in the North Atlantic that was born, according to some estimates, in 1505. Having determined the age of the fish using radiocarbon dating, they announced that this “old lady” may be the absolute record holder for life expectancy among vertebrates.

This shark is a species of Greenland, or arctic, shark that grows throughout its life, adding approximately 1 cm per year. The fact that some of them reach sizes of more than five meters indicates the enormous life expectancy of these fish. But it was only now possible to verify this.

They have learned to determine the age of sharks using radiocarbon dating. Scientists conducted radiocarbon dating of the nucleus of the lens of sharks' eyes.

Marine biologist Julius Nielsen from the University of Copenhagen discovered that the 5.4-metre Greenland shark his team studied was at least 272 years older than thought. She is already more than 512 years old.

The animal was found several months ago. The shark's potential age was determined in a study by the Arctic University of Norway, published in the journal Science. The shark may have been born in 1505, making it older than Shakespeare. Scientists are testing 28 other sharks of this species, all of which may also be long-lived.

These massive, slow-moving predators live in the cold waters of the Northern Arctic Ocean and in the North Atlantic. They reach sexual maturity at the “tender age” of 150 years.

Scientists attribute the longevity of this shark species to a very sluggish metabolism, as well as low temperatures. environment. Recent research has shown that cold environments can help slow down aging, and these centuries-old sharks are certainly proof of that.

Attacks on humans attributed to Greenland sharks are extremely rare. They live in cold waters where it is almost impossible to meet a person. However, there was a recorded case in which a Greenland shark followed a ship in the Gulf of St. Lawrence. Another shark chased a group of divers and forced them to the surface of the water.

Some fishermen believe that Greenland sharks damage gear and destroy fish, and regard them as pests. Therefore, when caught, they cut off the tail fin of the sharks and throw them overboard. Once caught, Greenland sharks offer virtually no resistance.

These Arctic centenarians are a kind of “time capsule”, and studying them can provide insight into the extent of the impact of human civilization on the oceans.

Last year, scientists managed to discover a Greenland shark, whose age exceeds 400 years - a record life expectancy among vertebrates! Of course, there is an explanation for this fact - the shark lives at great depths in the icy waters of the ocean, which significantly slows down its metabolism.

An international team of researchers conducted radiocarbon dating of the lens of the eyes of several Greenland sharks and found that their average lifespan is about 300 years, with scientists estimating the age of the oldest individual at almost four centuries or even more. Thus, Greenland sharks turned out to be the longest-living vertebrates. The study was published in the journal Science.

Greenland sharks are widespread in the north Atlantic Ocean and are found both at the surface and at depths of more than two thousand meters. The average body length of an adult typically reaches four to five meters, and the weight can reach up to 400 kilograms, making it the largest fish in Arctic waters. Due to the inaccessibility of their habitat, these animals have been little studied, but their slow annual growth (from 0.5 to 1 centimeter in length) suggested that they lived extremely long.

To determine the lifespan of Greenland sharks, researchers radiocarbon dated the nucleus of the eye lens of 28 female sharks. The fact is that the nucleus of the lens grows throughout the life of the animal, and the older the individual, the more layers of lens fibers the nucleus of its lens has. By removing these layers, scientists can get to the embryonic nucleus of the lens, which is formed in a shark before birth, and determine the age of the fish based on the carbon-14 isotope content in it.

The scientists' analysis showed that the average lifespan of Greenland sharks reaches at least 272 years, which makes them the longest-living record among vertebrates. Researchers estimated the age of the largest shark (502 centimeters long) at 392 ± 120 years, and individuals whose size was less than 300 centimeters turned out to be younger than a hundred years. The authors also state that Greenland sharks reach sexual maturity at approximately 150 years of age.

Thus, in terms of life expectancy, sharks were second only to the mollusks Arctica islandica, which live up to 507 years, and became the first among vertebrates, overtaking the previous record holder - the bowhead whale, some individuals of which live up to 211 years. Scientists cannot explain why Greenland polar sharks live so long, but they suggest that this is due to low temperatures waters in their habitats and, as a result, the slow metabolism of sharks.

The species was first scientifically described in 1801 as Squalus microcephalus. The specific name comes from the Greek words κεφαλή - “head” and μικρός - “small”. In 2004, it was determined that previously thought to be Greenland sharks living in the South Atlantic and Southern Ocean, they are independent species Somniosus antarcticus.

These are the northernmost and most cold-loving of all sharks. They are widespread in the north Atlantic Ocean - off the coast of Greenland, Iceland, Canada (Labrador, New Brunswick, Nunavut, Prince Edward Island), Denmark, Germany, Norway, Russia and the USA (Maine, Massachusetts, North Carolina). They are found on the continental and island shelves and in the upper part of the continental slope from the surface of the water to a depth of 2200 m. In winter in the Arctic and North Atlantic, Greenland sharks are found in the surf zone, in small bays and river mouths near the surface of the water. In summer they stay at depths of 180 to 550 m. In lower latitudes (Gulf of Maine and North Sea), these sharks are found on the continental shelf, migrating to shallow waters in spring and autumn. The temperature in their habitat is 0.6–12 °C. Sharks tagged under the ice off Baffin Island at the end of spring preferred to stay in the depths in the morning, and by noon they rose to shallow water and spent the night there.

Greenland sharks are apex predators. Their diet mainly consists of fish such as small sharks, rays, eels, herring, capelin, char, cod, sockeye salmon, catfish, lumpfish and flounder. However, sometimes they also hunt seals. Teeth marks on the bodies of dead seals off the coast of Sable Island and Nova Scotia suggest that Arctic Greenland sharks are their main predators in winter. On occasion, they also eat carrion: cases are described when the remains of polar bears and reindeer were found in the stomachs of polar sharks. They are known to be attracted to water by the smell of rotting meat.

TMAO, found in the tissues of Greenland sharks, helps stabilize enzymes and structural proteins that would otherwise not function properly due to cold temperatures and high pressure. Although in summer the temperature of Arctic waters can reach 10 and even 12 °C, in the middle of winter it can drop to −2 °C. Under such conditions, even the most stable proteins cease to function normally without chemical protection. The body of polar fish produces glycoproteins as antifreeze. Arctic sharks accumulate urea and TMAO to prevent the formation of ice crystals and stabilize proteins. At a depth of 2200 meters, the ambient pressure is about 220 atmospheres or 220 kilograms per square centimeter. It is not surprising that the concentration of the protective substance TMAO in the tissues of Greenland sharks is very high.

Attacks on humans attributed to Greenland sharks are extremely rare. They live in cold waters where it is almost impossible to meet a person. However, there was a recorded case in which a Greenland shark followed a ship in the Gulf of St. Lawrence. Another shark chased a group of divers and forced them to the surface of the water. Some fishermen believe that Greenland sharks damage gear and destroy fish, and regard them as pests. Therefore, when caught, they cut off the tail fin of the sharks and throw them overboard. Once caught, Greenland sharks offer virtually no resistance.

From the mid-19th century until the 60s of the 20th century, fishermen in Greenland and Iceland caught up to 50,000 Greenland sharks per year. In some countries, fishing continues to this day. Sharks are hunted for their liver oil. Raw meat is poisonous due to its high urea and TMAO content, causing poisoning not only in humans, but also in dogs. This poisoning is accompanied by convulsions and can be fatal. The traditional Icelandic dish hakarl is prepared from the meat of polar sharks through long-term processing. Sometimes these sharks are caught as bycatch when fishing for halibut and shrimp. The International Union for Conservation of Nature has assigned the species a conservation status of Near Threatened.

The polar shark belongs to the category of little-studied cartilaginous fish. Knowledge about her is insignificant. This is primarily due to the fact that the fish lives in harsh, cold waters, and besides, prefers to spend most of its life at depth. This is a predator. You can meet him in the White Sea, in the southern regions Barents Sea and in the waters of the Pechora Sea. Sometimes the fish migrates further east and ends up in the Kara Sea. She is a frequent visitor to the coast of Greenland, constantly lives in the coastal waters of northern Norway and is very fond of the waters of Iceland. It is also often found in the Baffin Sea and Hudson Strait.

Appearance

In terms of size, the polar shark successfully competes with the white shark. The length of her body reaches 6.5-7 meters. Weight fluctuates within a ton. There are specimens weighing up to 2 tons. Basically, the fish is 3-4 meters long and weighs no more than 800 kg. As for ferocity, here the predator is significantly inferior to its aggressive brothers. The body of the fish has an elegant, streamlined shape and is very similar to a torpedo.

The color of the skin can be dark green or brown. The entire carcass, from nose to tail, is strewn with small black and purple spots. The head, relative to the size of the body, is small. The shark's jaws are wide. The upper one has small, sharp and sparse teeth. On the lower jaw, the teeth grow much more densely, but they do not taper towards the top, but are square and blunt. The caudal fin, like that of most selachians, is asymmetrical in shape. Its upper part is larger than the lower part.

Reproduction and lifespan

This shark breeds in the spring. She lays several hundred eggs at a depth. Eggs oval shape and quite large. Their size reaches 8 cm. It is noteworthy that they do not have a protective cornea. These predatory fish live for about 40-50 years. The life expectancy of females is 10 years longer than that of males.

Behavior and nutrition

IN summer period The polar shark prefers to be at great depths. This is a water column from 500 to 1000 meters from the surface. Here it eats fish and invertebrates. It also feeds on carrion. The corpses of seals, walruses, and whales are its constant diet. It has not been observed to attack large living mammals. The fish is too cowardly, cautious and slow to allow itself to fight with a strong and fast animal. History also knows no cases of polar shark attacks on humans. In winter, it moves from the depths to the upper layers of water. At the same time, its diet does not change in any way, but this fish becomes available for catching.

Enemies

The main and perhaps the only enemy is man. The polar shark has a very large liver. Because of it, fish are caught, producing technical fat rich in vitamins from this organ. Predator meat is poisonous. This selachia does not have a bladder, and accordingly there is no urinary tract. Waste is excreted from the body directly through the skin. Local peoples who regularly catch polar sharks have learned to eat their meat. They soak it, boil it in several waters and only then consume it as food. Unprocessed meat has a strong alcoholic effect and a disgusting taste.