Pelagic largemouth shark - a rare species of shark: photo, video, description. All about sharks

Largemouth shark, or largemouth shark (lat. Megachasma pelagios)- one of the three species of sharks known to science that feed on plankton (in addition to whale and giant shark). Since its discovery in 1976, this deep-sea shark remains the only species in the family Megachasmidae. Until November 2004, fewer than 25 specimens were observed, of which only a few have been scientifically studied. Very little is yet known about the anatomy, behavior and range of this shark.

Peculiarities
The largest specimen measured was a dead female measuring 5.63 m, which washed ashore on April 19, 2004 near the city of Ichihara in Tokyo Bay. The smallest specimen was a male caught on March 13, 2004 near the island of Sumatra, whose size was 1.77 m. The most notable external sign, to which the largemouth shark owes its name, is a relatively large, rounded head with a short nose and a huge mouth. Her back is dark brown, her belly is lighter. The largemouth shark has two dorsal fins, one asymmetrical caudal fin, two large pectoral fins and two belly fins, of which the rear pair is much smaller.

Spreading
Largemouth sharks were found in the Atlantic, Pacific and Indian Ocean, most often, however, off the coast of California and Japan. From this, biologists conclude that this species is distributed throughout the world and prefers relatively warm latitudes. Mating appears to take place off the coast of California in the fall, as this is where the largest number of mature male largemouth sharks have been found.

Nutrition
Studies of the stomach contents of deceased animals have shown that the largemouth shark's main food is small organisms such as krill. Unlike the basking shark, which only passively filters water containing plankton, the greatmouth shark is able to actively suck in water for filtration. It is still unknown whether these animals also eat small fish.

Behavior
On October 21, 1990, scientists near California managed to catch a living male five meters in size. For the first time, a largemouth shark was able to be equipped with a radio transmitter and released into freedom. Thus, the first data on the migratory behavior of the shark, including its vertical movements, were obtained. It became known that the largemouth shark spends the night at a depth of about 15 meters, and during the day it descends to a depth of 150 meters. Presumably, the shark follows the krill, which changes its deep location in a similar rhythm.

Opening
It is impossible to say for sure whether people encountered this species in previous centuries and whether it gave rise to legends about sea ​​monsters, which are a mixture of a whale and a shark. It was first reliably caught on November 15, 1976, off the island of Oahu in Hawaii, after which it was described. It was a 4.46m long male that was caught by an American research vessel after it tried to bite through cables lowered into the water and got stuck in them. The animal was carefully studied and today its stuffed animal is kept in the Honolulu Museum.

The largemouth shark is one of the representatives of planktivorous predators, which also include whale and basking sharks.
The first time a person saw this sea animal was in 1976 near the island of Oahu in Hawaii. Despite its impressive size, this deep-sea fish for a long time coexisted with a person incognito. However, perhaps these particular sharks were the mysterious half-sharks, half-whales, about which the legends of many coastal peoples tell.

An amazing fact - even the surface of the Moon and many celestial bodies has been studied by humanity better than aquatic environment, next to which he lives.
From the time of the first capture of the big-headed shark to the present day, no more than three dozen individuals have been in the hands of scientists, incl. dead and thrown ashore by the sea. Therefore, much in the lifestyle and habits of this fish remains a mystery to this day.

Species name

Largemouth shark, pelagic largemouth shark, largemouth shark, megamouth shark.
Latin name- Megachasma pelagios (L. R. Taylor, Compagno & Struhsaker, 1983).

Taxonomy

• Order: Lamniformes
• Family: Megamouth sharks (Megachasmidae)
• Genus: Megamouth sharks (Megachasma)
• Species: Pelagic megamouth shark (Megachasma pelagios, L. R. Taylor, Compagno & Struhsaker, 1983)

The only species in its family.

Habitat

Due to little information about this shark, the boundaries of its range are difficult to determine. Presumably, it inhabits deep-sea areas of warm and warm-temperate seas, where single specimens were caught. Largemouths were most often caught off the coast of Japan and California.
Judging by the nature of its diet, it can be assumed that the largemouth shark is also found in cool waters, more saturated with krill and other zooplankton.

Dimensions

In 2004, on the coast of Japan, near the city of Ichihara, the largest specimen of a largemouth shark was discovered, the length of which was 5.63 m. It was a dead female, whose body was washed ashore by the waves. According to scientists, this size is not the maximum for largemouths. They may reach more than 7 m in length and weigh up to 1.5 tons.
The smallest specimen caught was just over one and a half meters in size (2004, near Sumatra Island).

Appearance

Main external hallmark largemouth is disproportionate big head and a huge mouth, thanks to which the shark got its name. The head is rounded, the front part does not protrude far forward, like most sharks. The teeth are small and frame the jaws of the fish like brushes. Their purpose is to filter water, preventing zooplankton captured by the mouth from escaping.
The color of the back is dark gray or brown-brown. The ventral side of the body is light. The fins are developed, the caudal one has a long upper blade (heterocercal).
Only in water does a shark have a body beautiful shapes- extracted onto land becomes shapeless under the influence of its own weight.

Diet

The food for largemouths is small aquatic life - zooplankton. By definition, planktonic organisms are organisms that are not capable of independent movement in water. Only currents and waves drive plankton. Planktivorous predators especially love to feast on krill - various small crustaceans present in the plankton mass of the oceans and seas.
The principle of eating largemouths is the same as that of its relatives and food competitors - basking and whale sharks. Opening its huge mouth wide, the predator captures a large volume of water and, filtering it through its gills and teeth, extracts plankton.

Behavioral features

The largemouth shark prefers deep-sea areas. It visits depths less than 20 meters only at night, chasing krill rising to the surface. Judging by the structure of the body, largemouths are slow predators. Their “cruising” speed when collecting prey does not exceed 2 km/h.

In October 1990, a live male captured near California fell into the hands of scientists. Its length reached 5 meters. Scientists managed to install transmitting equipment and instruments on his body, and then released the shark into the wild.
For more than two days, researchers had the opportunity to monitor the movements of the rare predator using transmitter signals. It was found that largemouths make daily vertical migrations, moving after the krill. The largemouth participant in the experiment spent the night at a depth of more than 150 m, and during the day it rose to a depth of 15 meters.

Structural features and interesting properties of the organism

The anatomical structure of this predatory fish not studied enough. General structure skeleton and internal organs characteristic of all sharks.

Reproduction

Like many other modern sharks, largemouth is an ovoviviparous species. Fertilization, development and hatching of eggs occurs in the womb.
Mating presumably occurs in the fall off the coast of California, where mature males were most often captured.

Threat of extinction

There is no way to estimate the population size of largemouth sharks these days. It is classified as a poorly studied animal species.

Danger to humans

Like any of the planktivorous predators, the largemouth shark can pose a danger to humans only due to its large body, which can injure a careless swimmer who loves to splash around at a depth of half a kilometer.

The pelagic largemouth shark is a real contender for a horror film. Anyone who saw this monster with an incredibly large mouth will remember this meeting forever.

But despite its rather creepy appearance, the pelagic largemouth shark is not scary for humans, since its diet consists of small shrimp and plankton, like the giant shark whale shark. And meet her at sea ​​waters for humans, this is a rather rare case: its main habitat is the deep ocean, which sometimes reaches 150-meter depths, and the shark rises to the upper fifteen-meter layers rarely and only at night.

The very first human encounter with a largemouth shark occurred in 1976, when an American vessel was conducting research on the seabed. Pacific Ocean near the Hawaiian Islands. To a depth of more than 4,600 meters, two special parachute anchors were lowered and then raised aboard the ship, which held the ship motionless on the ocean waves. An anchor got tangled in one of the riggings and a hitherto unknown shark was raised. The length of the shark was 4.46 meters, and the size of its mouth shocked everyone present. It was then that she was given the name pelagic largemouth shark (lat. Megachasma pelagios). Pelagic - because its main habitat is the “mesopilagil” zone (that is, the ocean depth is 150-500 meters), and why largemouth - look at these photos and everything will become clear to you.

Over the next forty years, the largemouth shark fell into human hands no more than three dozen times, as evidenced by photographs, and then mostly these were small specimens from 1.5 to 3 meters in length.

Only in 2004, scientists came into the hands of an already dead female largemouth shark, which was washed ashore in Japan by a storm. Its length was 5.63 meters, and according to scientists, this is not the limit of the growth of a shark, so maybe somewhere on great depths ocean, there are also seven-meter representatives of these sharks. But so far these are just guesses and assumptions, and the exact established facts are that pelagic largemouth sharks are distributed throughout the world where warm waters. Large concentrations of males have been recorded more than once in autumn period off the coast of California. This fact allows scientists to conclude that it is here at this time of year that mating occurs. Largemouths are an ovoviviparous species, that is, the female carries the cubs in her womb and small sharks are born. published

The pelagic largemouth shark is the only representative of its family, extremely rare view, about whose behavior and habitat very little is known. The largemouth shark is extremely different extraordinary diet, deep-sea habitat and enormous scientific potential. The small number of discovered individuals provided only a small fraction of theses about the peculiarities of the life of this animal; the largemouth shark remains a poorly studied species, but no less interesting.

Where does this name come from?

The largemouth shark, according to the few existing documents, looks like a mixture of a whale and a representative of a shark. The family, in which this animal is the only representative, received its name for its huge mouth, which is necessary for swallowing masses of water. Such an individual is one of three subspecies that are not active predatory image life. Along with tiger and giant sharks, this animal “weeds out” small crustaceans from the water.

The prefix “pelagic” in the form of these individuals means that they live away from continental shelf at a depth of over 100 meters. Representatives of this family belong to oceanic fish and prefer warm waters, for example, near Hawaii and California. The largemouth shark is extremely rare and is the only representative of its family.

History of species discovery

The first documented evidence of the existence of the pelagic largemouth shark dates back to 1976. Data is extremely scarce, since there are barely 100 individuals of this family in the world. Only a few animals were at the disposal of scientists, the structure of whose organisms became the object of several scientific works dedicated to this subspecies.

The first member of the family was discovered on November 15, 1976 in Hawaii, its length reached 4.46 meters. At first, the animal was mistaken for another representative of sharks - a tiger shark; there are also frequent cases when a large-mouthed shark was confused with a killer whale, since the colors of these two animals are similar.

Features of the structure of the body

The average size of a pelagic largemouth shark is about 4.5 meters, maximum length– 5.7 meters. The body is brown, less often gray, the tissues are filled with water, as is the case with other representatives of sharks, the skeleton consists of soft cartilage. This representative also needs constant movement, otherwise the individual will simply drown. The teeth are not intended for active predation, the nose is blunt. The fish's temperament is extremely calm and its behavior is slow.

Habitat

Pelagic largemouth shark belongs to the class deep sea fish, its habitat is at a depth of up to 500 meters. However, the maximum recorded depth of habitat for this fish is about 2500 meters. Color and impressive size serve warning for possible predators, since this species of shark does not have sharp teeth for protection. Individuals can migrate to search for food, but prefer tropical and subtropical waters.

The reproductive features of this species are unknown; it is quite logical to assume that this process occurs in a similar way as in the giant shark. Unlike whales, which passively filter water through their baleen, the greatmouth shark makes swallowing movements every few minutes. Whether the fish is capable of hunting is unknown this moment The basis of its diet is considered to be plankton, which consists of small crustaceans and jellyfish.

Habits

The pelagic largemouth shark spends most of its life on the move. At night, an individual of this species does not dive to more than 15 meters, while during the day it searches for plankton at a depth of more than 150 meters. Migration within waters occurs mainly due to the movement of plankton, which is also characterized by change of location depending on the sleep or wakefulness of predators. Scientists admit that previously the largemouth shark was benthic, that is, it lived in close proximity to the bottom, which was the reason for such a late discovery of the individual by people.

Natural predators and enemies of the largemouth shark

As mentioned above, the largemouth shark has few natural predators, which is primarily due to the enormous size of the individual. However, some types of predators still hunt these animals, namely:

• rock bass;
• sperm whale;
• other sharks.

Predators take advantage of the slowness of this largemouth shark and simply tear out pieces of meat from its body, which is why many animals there are scars on the body. The observed individuals also had marks on their faces from collisions with stingrays and jellyfish. It is unlikely that this is a direct attack, but rather a matter of self-defense, since the largemouth swallows huge masses of water in an attempt to filter out the krill.

Largemouth shark: is it dangerous for people?

This pelagic species is practically harmless to people and can only cause harm to divers who, through carelessness, find themselves in close proximity to the mouth of this giant. Otherwise, the largemouth shark is extremely different calm and good-natured disposition. In turn, the degree of influence of anthropogenic factors on this shark species is unknown; it is quite possible that this pelagic shark species requires protection.

Heroine of myths and legends

The pelagic largemouth shark could well have become the progenitor of numerous myths about sea monsters, several factors speak about this:

• frightening appearance, including a huge mouth;
• large sizes;
• resemblance to cetaceans;
• living in deep water.

As with the giant squid, the pelagic megamouth shark may have served as a breeding ground for the emergence of various myths, dedicated to huge ocean fish that can swallow a ship. This subspecies tries to avoid contact with people.

It is noteworthy that most representatives of this family were discovered already dead. The last recorded case of contact with an individual of this subspecies was in 2015; the discovered remains are highly valued by museums, as they make it possible to study the habits of the largest deep-sea representative of the subspecies. Meanwhile, largemouth sharks become victims not only of attacks by predators, but also of fishing, because their meat is highly valued in several world cuisines.

Some scientists insist that it is necessary to include this individual in the list of species that are on the verge of complete disappearance and ban large-scale shark fishing. However, the data found is not enough to draw a conclusion regarding the current position of the species and the number of individuals. The last recorded number of largemouths was 102 individuals, which is disproportionately low compared to other members of the species.

There is an opinion that largemouth sharks will be among the species that will disappear in the next decade due to anthropogenic water pollution. However, it is too early to draw conclusions about the future of these individuals.

IN sea ​​depths such fish as the largemouth shark live. Its habitat covers tropical, subtropical and temperate regions of the World Ocean. Despite the fact that the name contains the word “shark,” this species feeds only on plankton, small fish and jellyfish. The fish swims with an open mouth, which is enormous in size, and obtains food by sucking and filtering water.

These remarkable marine inhabitants became known only in November 1976, when the first such fish was caught near Hawaii. It reached 4.5 meters in length and weighed 750 kg. This find became a sensation in ichthyology of the last century. And her stuffed animal was placed in the Honolulu Museum.

To date, this species has been poorly studied, since it rarely comes into view of people. A little more than a hundred of these sharks were caught, and only a few of them were examined by specialists. The body is black-brown above, the belly is light. The tail has a larger upper lobe and is generally similar to the tails of other shark species.

The muzzle is wide and rounded. The mouth is large with small teeth. It is surrounded by luminous photophores (special glands) that attract plankton and small fish. The mouth of a largemouth shark reaches a width of 1.3 meters. There are 50 rows of teeth in the upper jaw, and 75 in the lower jaw. The gill slits have an elongated shape. The skin is relatively soft. These fish grow up to 5.7 meters in length. Weight reaches 1.2 tons.

Puberty in males occurs at a body length of 4 meters, in females the corresponding value is 5 meters. This species is viviparous. But extremely little is known about reproduction based on the few specimens of both sexes captured.

Largemouth sharks feed at depths of up to 1500 meters. The most optimal depth for them is 120-170 meters. And only occasionally do representatives of the species rise to a depth of 40 meters, and in shallow bays they can even be found at a depth of 5 meters. This makes it clear why they so rarely catch the eye of people.

In the water column, this fish opens its huge mouth wide and swims through the accumulation of krill. From time to time she closes her jaws and squeezes her throat tightly to compact the food. After this, it is swallowed, and the mouth opens again to swallow the next portion of krill. For more efficient hunting, the jaws have the ability to move forward. This allows the fish not to wait for the food to swim into its mouth, but to suck it in.

To study the behavior of this species, a 5-meter largemouth shark was caught in California waters in 1990. A sensor was placed on her body and she was released. He transmitted information about the depth and speed of movement for 2 days. IN daytime it showed a depth of 120-160 meters. At night the fish rose to a depth of 12-25 meters. At the same time, she swam all the time at a speed of 1.5-2.1 km/h. This picture is common for many sea ​​creatures, which track plankton in the water column.

Despite the fact that sharks of this species have large sizes, they do not pose a danger to people. It should also be noted that they are not in commercial demand. Judging by the reviews, their meat is quite edible, but does not have high taste qualities. If this fish accidentally gets caught in the net, it is usually thrown overboard.

The only people who are interested in representatives of the species are ichthyologists, as well as workers of aquariums and museums. There is no information on the number of largemouth sharks.