Why do jellyfish appear on the shores of the Black Sea? Jellyfish are mysterious loners

Many of those who vacationed at sea encountered jellyfish. This helped to realize the fact that they cannot be called ordinary and harmless creatures. Let's look at some Interesting Facts about jellyfish.

What does science know about jellyfish?

Researchers believe that jellyfish have been around for about 650 million years. They are found in all layers of each ocean. Various live in both salty and fresh water. Their primitive nervous system, which is located on the epidermis, allows them to perceive only smells and light. The nerve networks of jellyfish help them detect another organism through touch. These "animal plants" essentially have no brain and sense organs. They do not have a developed respiratory system, and breathe through thin skin, which absorbs oxygen directly from the water.

While exploring interesting facts about jellyfish, scientists noticed that these creatures are able to positively influence people experiencing stress. For example, in Japan they breed jellyfish in special aquariums. Their smooth and measured movements act as a sedative. Although such pleasure is expensive and causes additional troubles, in general it is justified.

Jellyfish are more than 90 percent water. The venom from their tentacles is used as a raw material for drugs that regulate blood pressure and to treat respiratory diseases.

It was called the “Portuguese man-of-war” by some 18th-century sailors who liked to tell others about the jellyfish floating like a Portuguese warship of the Middle Ages. In fact, her body is very similar to this vessel.

Her official name- physalia, but this is not one organism. We are talking about a colony of jellyfish and polyps in different modifications, which interact very closely and therefore look like one creature. The poison of some types of physalia is deadly to humans. Most often, the habitats of the Portuguese man-of-war are limited to the subtropical parts of the Indian and Pacific Oceans, as well as the northern bays of the Atlantic Ocean. In more rare cases, they are carried away by currents into the waters of the Caribbean and Mediterranean seas, to the shores of France and Great Britain, to the Hawaiian Islands and the Japanese archipelago.

These jellyfish often swim in huge groups of several thousand individuals in warm waters. The transparent and shiny jellyfish body rises above the water by about 15 centimeters and moves along a chaotic trajectory regardless of the wind. Those individuals that swim near the shore are often thrown onto land by powerful winds. In the warm season, physalia swims away from the shore; it moves with the current towards one of the earth's poles.

Distinctive features of physalia

Other interesting facts about this type of jellyfish concern their unique features. Physalia is one of two species that can glow red. Another Portuguese warship uses its air bag filled with nitrogen as a sail, carbon dioxide and oxygen. If a storm approaches, the jellyfish releases its bubble and goes under water. Small perches like to swim near its tentacles; they do not sense a toxic environment and have serious protection from enemies, as well as food particles. Perches attract other fish with their appearance, which become food for these invertebrates. This is such a symbiosis.

There are a considerable number of species known today as physalia. In the Mediterranean Sea alone, researchers have discovered about 20 species of Portuguese man-of-war.

Physalia jellyfish, interesting facts about reproduction

It is not known exactly how this jellyfish reproduces. However Scientific research showed that they reproduce asexually, and in each colony there are polyps that are responsible for reproduction. In fact, they are the ones who create new colonies. Portuguese man-of-war They differ in that they can reproduce continuously, which is why the number of nascent jellyfish in the waters of the oceans and seas is growing.

Another common version of the reproduction of physalia indicates that, when dying, the jellyfish leaves behind some organisms that exhibit sexual characteristics, after which new individuals are formed. This theory has not yet been proven.

About the tentacles of the Portuguese man-of-war

Regarding the jellyfish tentacles, the interesting facts are that their structure is unique. The “limbs” of jellyfish are equipped with a large number of capsules containing poison, the composition of which is similar to the poisonous substance of a cobra. Each of these small capsules is a hollow, twisted tube with fine hairs. If contact occurs between the tentacles and the fish, the fish will die due to the stinging mechanism. When a person gets burned by this jellyfish, he experiences sharp pain, he will develop a feverish state and have difficulty breathing.

The interesting facts about jellyfish don’t end there. The tentacles of these invertebrates can reach 30 meters in length. In addition, a person who is engaged in swimming, enjoying the process itself, will not always be able to see a bright blue-red bubble on the water and realize the danger that threatens him.

Irukandji jellyfish: interesting facts about the danger posed by it

This small jellyfish, which lives off the coast of Australia, produces toxic substances that act stronger than poison cobras There are 10 types of Irukandji, 3 of which are deadly. The bite is almost imperceptible, but its consequences are a powerful heart attack, which in some cases can result in painful death. And all this can happen in just 20 minutes. Because these invertebrates are so small and virtually invisible, they can easily penetrate any barrier net that is designed for large creatures that pose a danger to swimmers and vacationers.

There are some other interesting facts about this species of jellyfish. Since fishermen often fell ill with a strange disease after each trip to the sea, they realized that the reason for this was contact with some kind of sea creature. The jellyfish was named after the Irukandji tribe. Over time, thanks to Dr. Barnes, it was finally possible to establish that the cause of the disease was contact with jellyfish. Although its size is quite small, its tentacles reach a length of 1 meter. The pain from the bite is so severe that it forces you to double over, is accompanied by severe sweating and vomiting, and your legs tremble violently.

conclusions

Although these invertebrate organisms are difficult to see in the water, regardless of their size, you still shouldn’t be careless and inattentive while swimming in the sea or walking along the shore - for the sake of your health. Many types for human health and life.

However, they also perform useful functions in their habitats and are used in medicine as raw materials for drugs. And who knows, maybe humanity will be able to get even more benefits from jellyfish.

Scientists do not give a definite answer to the question of how long jellyfish live. Many agree that life cycle These animals are short-lived and the lifespan of most species ranges from two to six months.

Recently, zoologists discovered that among representatives of this species there are specimens that never die and are always reborn. That is why the Turitopsis Nutricula jellyfish is considered to be the only immortal creature on the planet.

Who are jellyfish

When zoologists talk about jellyfish, they usually mean all mobile forms of coelenterate cnidarians (a group of multicellular invertebrate representatives of the animal world) that catch and kill their victims with the help of tentacles.

These amazing animals live only in salt water, and therefore they can be found in all oceans and seas of our planet (except internal ones), sometimes in closed lagoons or lakes with salt water on coral islands. Among the representatives of this class there are both heat-loving animals and those that prefer cold waters, species that live only near the surface of the water, and those that live only on the bottom of the ocean.

Jellyfish are solitary animals, since they do not communicate with each other in any way, even if currents bring them together, thus forming a colony.

We got ours modern name these creatures in the middle of the 18th century thanks to Karl Lineus, who hinted at the mythical head of the Gorgon Medusa, the resemblance to which he noticed in these representatives of the animal world. This name is not without reason, since these animals are similar to it.

This amazing animal consists of 98% water, and therefore has a transparent body with a slight tint, which in appearance resembles a jelly-like bell, umbrella or disk that moves by contracting the muscles of the bell wall.

Along the edges of the body there are tentacles, the appearance of which directly depends on what species it belongs to: in some they are short and thick, in others they are long and thin. Their number can vary from four to several hundred (but always a multiple of four, since representatives of this class of animals are characterized by radial symmetry).

These tentacles consist of string cells that contain poison and are therefore directly intended for hunting. It is interesting that even after death, jellyfish are able to sting for another fortnight. Some species can be deadly even to humans. For example, the animal known as " Sea Wasp"is considered the most dangerous poisonous animal in the world's oceans: scientists claim that its poison is quite enough to poison sixty people in a few minutes.

The outer part of the body is smooth and convex, while the lower part resembles a bag. In the center of the lower part there is a mouth: in some jellyfish it looks like a tube, in others it is short and wide, in others it resembles short clubs. This hole also serves to remove food debris.

These animals grow throughout their lives, and their size largely depends on the species: among them there are very small ones, no more than a few millimeters, and there are also huge ones, the body size of which exceeds two meters, and together with the tentacles - all thirty ( for example, the largest jellyfish in the world's oceans, Cyanea, which lives in the North-West Atlantic, has a body size of more than 2 m, and with tentacles - almost forty).


Despite the fact that these marine animals lack brains and sensory organs, they have light-sensitive cells that act as eyes, thanks to which these organisms are able to distinguish darkness from light (they, however, are not able to see objects). Interestingly, some specimens glow in the dark, with species living at great depths having a red light, and those living closer to the surface having a blue light.

Since these animals are primitive organisms, they consist of only two layers, connected thanks to a special adhesive substance - mesoglia:

  • external (ectoderm) - a kind of analogue of skin and muscles. The rudiments of the nervous system and germ cells are also located here;
  • internal (endoderm) - performs only one function: digests food.

Methods of transportation

Since all representatives of this class (even the largest individuals, whose weight exceeds several centners) are almost unable to resist sea currents, scientists consider jellyfish as representatives of plankton.

Most species still do not completely succumb to water flows and, although slowly, move, using the current and the thin muscle fibers of their body: contracting, they fold the body of the jellyfish like an umbrella - and the water that is in the lower part of the animal is sharply pushed out.


As a result, a strong jet is formed, pushing the animal forward. Therefore these sea ​​creatures always move in the direction opposite to the mouth. They are helped to determine where exactly they need to move by the balance organs located on the tentacles.

Regeneration

One more interesting feature of these creatures is their ability to restore lost parts of the body - absolutely all the cells of these animals are interchangeable: even if this animal is divided into parts, it will restore them, forming two new individuals! If you do this with an adult jellyfish, an adult copy will appear; from a jellyfish larva, a larva will appear.

Reproduction

Looking at these amazing translucent creatures, many ask themselves the question of how jellyfish reproduce. Reproduction of jellyfish is an interesting and unusual process.

Answering the question of how jellyfish reproduce, it is worth noting that in this case, it is possible both sexually (they are heterosexual) and vegetative propagation. The first involves several stages:

  1. In these animals, the sex cells mature in the gonads;
  2. After the eggs and sperm mature, they come out through the mouth and are fertilized, resulting in the appearance of a jellyfish larva - a planula;
  3. After some time, the planula settles to the bottom and attaches itself to something, after which a polyp appears on the basis of the planula, which reproduces by budding: on it, layering on top of each other, daughter organisms are formed;
  4. After some time, they peel off and float away, revealing themselves as a newly born jellyfish.
    The reproduction of some species differs somewhat from this pattern. For example, the pelagic jellyfish does not have a polyp stage at all - the cubs appear directly from the larva. But bougainvillea jellyfish can be said to be born, since polyps are formed directly in the gonads, without separating from the adults, without any intermediate stages.


Nutrition

These amazing animals are the most numerous predators on our planet. They feed mainly on plankton: fry, small crustaceans, fish caviar. Larger specimens often catch small fish and smaller relatives.

Thus, jellyfish see almost nothing and do not have any sense organs; they hunt with the help of scribbling tentacles, which, when they sense a touch on them, edible food, they instantly inject poison into it, which paralyzes the victim, after which the jellyfish eats it. There are two more options for catching food (much depends on the type of jellyfish): the first is that the prey sticks to the tentacles, the second is that it gets entangled in them.

Classification

There are the following types of jellyfish, differing from each other in structure.

Hydromedusa

Hydroid jellyfish are transparent, small in size (from 1 mm to 3 cm), four tentacles and a long tube-shaped mouth are attached to the body. Among prominent representatives hydromedusa - jellyfish Turritopsis nutricula: the only creature discovered by people about which scientists have declared that it is immortal.

Having reached maturity, it sinks to the bottom of the sea, transforming into a polyp, on which new formations are formed, from which new jellyfish subsequently arise.

This process is repeated more than once, which means that it is constantly reborn, and can die only if it is eaten by some predator. These are the interesting facts about jellyfish that scientists recently told the world.

Scyphojellyfish

Scyphoid jellyfish have a more complex structure compared to hydromedusae: they are larger than representatives of other species - the largest jellyfish in the world, the Cyanea jellyfish, belongs precisely to this class. This giant jellyfish At about 37 meters long, it is one of the longest animals on Earth. Therefore, she eats a lot: during her life, the largest jellyfish eats about 15 thousand fish.

Scyphojellyfish have a more developed nervous and muscular system, a mouth surrounded by a huge amount stinging and tactile cells, and the stomach is divided into chambers.


Like all jellyfish, these animals are predators, but deep-sea animals also feed on dead organisms. The touch of a scyphoid jellyfish to a person is quite painful (the feeling as if bitten by a wasp), and a mark resembling a burn often remains at the point of contact. Its bite can also cause an allergic reaction or even painful shock. Having seen this animal, it is advisable not to take risks and, when swimming past, not to touch it.

Some of the most striking specimens of this species, in addition to the Cyanea jellyfish, are also the Aurelia jellyfish (the most typical representative) and the Golden jellyfish - an animal that can only be seen on the Rocky Islands archipelago in Palau.

The golden jellyfish is notable for the fact that, unlike its relatives, who live only in the seas, it lives in Jellyfish Lake, which is connected to the ocean by underground tunnels and is filled with slightly salted water. Representatives of this species also differ from marine species in that they completely lack pigment spots, have no stinging tentacles, and no tentacles that surround the mouth.

Although the golden jellyfish is a scyphojellyfish, over many years it has turned into a completely different species that does not pose a danger to humans, since it has significantly lost its stinging ability. An interesting fact is that the Golden Jellyfish began to grow green algae on its body, from which it receives part of its nutrition. The Golden Jellyfish, like its marine relatives, feeds on plankton and has not lost the ability to migrate - in the morning it swims to the east coast, in the evening it swims to the west.

Box jellyfish

Box jellyfish have a more advanced nervous system compared to other representatives of the cnidarian class. They are the fastest of all jellyfish (able to reach speeds of up to 6 m/min) and can easily change the direction of their movement. They are also the most dangerous representatives of jellyfish for humans: the bites of some representatives of box jellyfish can be fatal.

The most poisonous jellyfish in the world belongs to this species, lives near the Australian coast and is called the Box Jellyfish or Sea Wasp: its poison can kill a person in just a few minutes. This wasp is almost transparent, of a pale blue hue, which is why it is difficult to notice on the water, which means it is easier to stumble upon it.


The Sea Wasp is the largest jellyfish in its class - its body is the size of a basketball. When a sea wasp simply swims, its tentacles are reduced to 15 cm in length and are almost invisible. But when the animal hunts, they stretch out to three meters. Sea Wasps feed mainly on shrimp and small fish, and they themselves are caught and eaten by sea turtles - the only animals on our planet that are insensitive to the poison of some of the most dangerous creatures on Earth.

Any of us has seen the simplest mirages. For example, when you drive on a heated asphalt road, far ahead it looks like a water surface.

Jellyfish have lived on earth for over 650 million years. They appeared before dinosaurs and sharks. These creatures inhabit all the seas and oceans of the world. Some species even live in freshwater lakes and rivers. What do we know about them, other than their wet reputation as merciless stinging creatures? Let's take a more peaceful look at these beautiful and mysterious creatures.

"Medusa! Medusa!" - timid tourists shout in horror when they see a gelatinous drop floating near the shore. I don’t mean those whitish cakes, torn to shreds, flopping along the Crimean coast of the Black Sea. We are talking about more exotic shores. Falling under the power of stereotypes, people react to jellyfish with the greatest fear. This fear is in many cases completely unfounded, because stinging jellyfish are found in certain places. "Gelatinous" creatures are often mistaken for brutal killers, whose deadly sting must be feared like fire. But despite their “bad” reputation, most jellyfish are completely harmless. We also know nothing about the beauty of these sea wanderers. When talking about jellyfish, people most often imagine a jelly-like suspension drifting off the shore of a beach. In fact, jellyfish are one of the most stunning and stunningly beautiful sea creatures.

The jellyfish got its name because of its resemblance to the moving hair-snake of the legendary Gorgon Medusa from Greek mythology. Jellyfish seem like supernatural creatures largely due to their strange shapes and colors. Nature created them in a special way: their body resembles an umbrella, or a bell, sometimes a ball. Jellyfish have the most incredible sizes. Their diameter can range from three millimeters to two and a half meters. The most common jellyfish are the size of a saucer. The smallest jellyfish is the size of a thimble. This little one lives in the Caribbean. And the largest is the so-called “lion’s mane,” which lives in the Arctic Sea. Body " sea ​​lion" reaches two and a half meters wide, and its tentacles are thirty-seven meters long (that's almost half a football field!).

In the seas and oceans of our planet, biologists have counted more than two hundred various types jellyfish This, of course, is not the limit - many have simply not been found yet. The jelly-like body of these sea vagrants is most often completely transparent, or pale blue, white or pink. The transparency of sea skirts is a very useful camouflage in open habitats where there is no place to hide from predators. But their most unusual bright colors are also found in nature: yellow, blue, purple, lilac, orange and red. Some jellyfish glow in the dark with a cold light - this is called luminescence.

Jellyfish is also surprising because it is unlike any other animal on Earth. What are these creatures that are, so to speak, neither fish nor fowl? These are close relatives sea ​​anemones and corals that do not have a bone base. They are ideally designed to live in water. Jellyfish are approximately 95% water, 3-4% salt and 1-2% protein. They also have no heart, no eyes, no circulatory system, no gills. Most jellyfish consist of three parts: a gelatinous body; tentacles that sting and catch prey; and an openwork mouth that absorbs food.

Eyeless creatures are very fragile - their tissues are easily damaged. But they can partially restore their tentacles and other body parts. Unlike fish, which retain their shape even if taken out of the water, the light figure of a jellyfish is supported by water environment. Take the jellyfish out of the water and see for yourself how it instantly turns into a flat, trembling drop.

Despite some limitations in the senses, the jellyfish can smell, taste, sense odors and balance with the flow, it also distinguishes light from darkness. With the help of special bags located on the sides of its “bell”, the jellyfish maintains its balance. In the inner ear of people there are sacs with similar functions. Water currents also help the jellyfish swim. This graceful creature swims against the current on its own, moving in a reactive manner: pushing water out of the cavity of its “bell.” One variety Mediterranean jellyfish, which measures about six centimeters in diameter, can move up or down a distance of just over a kilometer in one day. This is equivalent to a distance of 61 kilometers for a person 1 m 80 cm tall!

You will be surprised to know how a jellyfish breathes. As, indeed, is the fact that she breathes at all. Her breathing is very different from the breathing of a person or even a fish. The jellyfish does not have lungs or gills, or indeed any other respiratory organ. The walls of its gelatinous body and tentacles are so thin that oxygen molecules freely penetrate through the jelly-like “skin” straight into internal organs. Thus, the jellyfish breathes over the entire surface of its body.

These soft-bodied animals are also amazing because they grab food, as they say, without the help of arms and legs. The permanent menu of sea “jelly” consists of plankton. They also feed on fish eggs and tiny crustaceans. The tentacles of jellyfish, which have a thread-like structure, lure prey, driving it into the streams. oral cavity. Many people and these sea ​​predators considered a delicacy. They are dried in a special way, after which, according to gourmets, they taste great. Moreover, they are low in calories and rich in nutrients.

Along the edges of the jellyfish’s “bell” there are tentacles with stinging cells that can cause burns. Tiny "harpoons" embedded in their thread-like legs paralyze their prey. Stinging jellyfish calmly watch for unwary swimmers, who also become victims of their toxin. Even if you break this merciless creature in the water into thousands of pieces, it will not save you - they will turn into thousands of tiny monsters that are also capable of stinging. Stinging jellyfish dominate the Chesapeake Bay of the Atlantic Ocean off the coast of the United States. The “moon” jellyfish is often found here in the height of summer and until late autumn. The sting of such a jellyfish is similar to the sting of a bee - the consequences are also painful. And remember that a stinging jellyfish washed ashore is still dangerous as long as its tentacles are raw.

Although they bring harm to people, these burning creatures are vital for smaller animals - tiny fish and crabs, which quietly cling to them from below and thus calmly travel on their “master”. But this is not all the merits of poisonous creatures to nature. For example, the Eastcoast stinging jellyfish, a resident of the Chesapeake Bay, feeds on another gelatinous predator that preys on local oysters. This jellyfish is called the "comb" because it appearance resembles a toothbrush. These comb jellyfish (sometimes called sea jellyfish) walnuts) cause people panic fear. They differ from other jellyfish in that they do not have a sting. Therefore, neither swimmers nor beachgoers have anything to fear from them. Comb jellyfish are most commonly found near Baltimore in Atlantic Ocean. They eat small oysters in such quantities that it quickly reduces their population. Due to the great appetite of this “comb”, small oysters simply do not have time to grow. And therefore, the fewer “combs” that live in the bay, the more oysters there are. “Combs” are the favorite food of stinging jellyfish. The “istkosta” itself ends up for lunch sea ​​turtles– this is also a kind of merit to Mother Nature.


Some types of jellyfish not only “sting”, but also kill humans with their deadly sting. For example, the “sea wasp” that lives in the seas of Australia. Up to 65 people die from its sting every year. Its venom is more deadly than that of a cobra. Death occurs within three minutes. And there is no way to escape - it’s better not to meet her at all. But if you are stung by a stinging jellyfish, there is a way to calm the pain. First, remove any remaining tentacles and rinse the stung area. sea ​​water. Then wipe the area with food vinegar, which will stop the action of the sting - it will no longer be able to release poison. Next, apply shaving cream to the damaged area of ​​skin - the stings will stick into it, and then scrape off the dried cream. The pain will subside in about an hour. If painful reactions persist, you should immediately consult a doctor.

For most people, jellyfish venom causes only painful irritation. But for some, the consequences of a burn can become more fatal if an allergic reaction begins to develop in a person. It is also called anaphylactic attack. In this case, treatment of the damaged skin area is urgently needed! An allergic reaction can be very diverse: from rash and itching to shortness of breath. Anaphylaxis can swell the skin on your throat, making it difficult to breathe. The only remedy for it is the injection of synthetic adrenaline. Aloe gel will also soothe the pain. But the best treatment is to look both ways when swimming. Before you go swimming in an unfamiliar place (and since you are at a resort, the place will be unfamiliar), ask the local aborigines or more experienced tourists, do stinging jellyfish live here?

Today, scientists studying the life of these fascinating creatures recognize the importance of the role they play in the biological life of the seas and oceans. What types of jellyfish are researchers primarily interested in? Some scientists are still looking for an effective antidote that will save the lives of people stung, for example, by a “sea wasp.” Others are studying the structure and composition of jellyfish to use as a medicine against cancer and other terrible diseases. The substance, derived from a jellyfish found in the northwest Pacific Ocean, is already being used for medicinal purposes. Some types of these amazing creatures doctors successfully use it in the treatment of cancer and cardiovascular diseases. This is far from a complete track record of jellyfish; in the future, medicine will find other areas of their application.

I hope that after reading the article your view of jellyfish will become more friendly, and these “gelatinous” sea nomads will no longer frighten you.

Jellyfish are a class of multicellular invertebrates that hunt and kill their victims using tentacles.

These beautiful exotic creatures can only survive in salt water, therefore, their habitat is oceans, seas and in some cases cut off from " big water» lagoons coral islands. Some of the species love cool water, others - warm, others live only in the upper layers, and others - only at the bottom.

It is interesting that the representatives of the animal world in question belong to the same group as... corals. Both of these classes of creatures belong to the coelenterates.

Jellyfish are loners. They do not transmit signals to their “relatives” in any way, even if they are swept into a large pile by the current.

Their name was given to them in the mid-18th century by Carl Linnaeus, who noticed their similarity to the head of the famous character of ancient Greek myths - the Gorgon Medusa.

This is an amazing animal 98% consists of water, therefore, its body is almost transparent, similar to a dome, umbrella or disk made of jelly. And the “dome” moves due to muscle contraction.

Tentacles

There are tentacles along the edges of the creature. They are very different different types: short and thick are possible, long and thin are possible; their number ranges from four to four hundred (the number of tentacles is always a multiple of four, because these animals have an inherent radial symmetry).

Tentacles are built from containing poisonous substances of stinging cells and are needed for movement, hunting and holding prey. Fun fact: even a dead jellyfish can bite for about two weeks. Selected species Jellyfish are extremely dangerous for humans. For example, an animal called the Sea Wasp can poison six dozen people in a couple of minutes.

From above the animal’s body is smooth and dome-shaped, and from below it looks like an empty bag. In the middle below is the mouth opening. It can also be different: in some individuals it looks like a pipe, in others it looks like a club, in others it is wide. Undigested food remains are also removed through the mouth.

Growth and development

Jellyfish increase in size throughout their lives, and their final size depends on the species. There are tiny ones, no longer than a couple of millimeters, but there are giants larger than forty meters(this is the length of the tentacles). Cyanea - largest representative, lives in the North Atlantic.

These inhabitants of the sea no brain or sense organs, but there are light-sensitive cells that help them distinguish between darkness and light (they do not see objects). Some specimens can glow in the dark. Animals living in the depths are usually red, and those living near the surface of the water are blue.

Internal structure

The internal structure of animals is very simple. They consist of two layers:

  1. The outer ectoderm, which acts as a kind of skin and muscle, contains the rudiments of nerves and germ cells.
  2. Internal endoderm, which only digests food.

Jellyfish have an amazing ability to regenerate: even if you cut an animal into halves, two similar individuals will grow from them.

Classification

  1. Hydroids or Hydrozoa(organisms that live only in waters that constantly contain absorbed oxygen). Relatively small (1 to 3 cm), transparent animals; four tentacles, a long mouth resembling a tube. The most famous creature of this class- Turritopsis nutricula. This the only thing known to science biologically immortal being. Having aged, it sits on the seabed and transforms into a polyp, from which new individuals then grow. Another very dangerous animal called the Cross belongs to this class. It is tiny (the largest individuals reach about 4 cm), but if it bites a person, the victim will have serious and very long-term health problems.

  1. Box jellyfish (Cubozoa). This class is so named because their umbrella is not oval, but cubic. They differ from other representatives in their developed nervous system. They can swim at speeds of up to six meters per minute and adjust direction with ease. However, they are also the most dangerous for people: some individuals can even kill a careless swimmer. The most poisonous representative of cnidarians on the planet, the Sea Wasp, is a representative of this class.
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    I live in Crimea and have long observed that there are a lot of jellyfish when the sea warms up well - this is in the middle of August. During this period, the sea glow is still observed in the evening, i.e. glow of marine organisms occurs.

    At the end of summer - August (second half and September). But the number of these same jellyfish is impossible to predict. This depends on sea currents and water temperature. Therefore, if you are interested in looking at jellyfish, plan your vacation for this time of year.

    Closer to the onset of autumn, jellyfish in the Black Sea become noticeably more numerous. In addition, they can appear in July; we went on vacation once, and the sea was swarming with them when the water was warm and sticky. So it’s better to rest at the beginning of summer if you don’t like them.

    Jellyfish appear in the Black Sea in August and September. The water is very warm at this time, especially off the coast.

    I literally saw an invasion of jellyfish in the second half of August on the Central Beach in Sochi. At first we didn’t even understand what was happening to the water - it turned silver in the sun and was somehow unusual. And when we got closer, we saw that there were jellyfish, apparently and invisible! They were of all sizes - from very tiny to quite large. They penetrated the water column.

    The waves washed them ashore, the children collected them and sent them back to the sea. Moreover, there were vacationers who were not embarrassed by the full sea of ​​jellyfish, and they swam! No one complained of a burn or bite. The jellyfish were good). But we didn’t dare to swim that day. The next day they almost completely disappeared, the sea near the shore cleared, and only single jellyfish were found.

    I visited the Black Sea for the first time at the end of July, in the port city of Tuapse. And there were jellyfish, at first there were not many of them, occasionally they were washed ashore by a wave. Mostly small.

    And then a couple of days later there was a storm and the next morning there were a lot of them in the sea, from large to small. I didn’t dare to swim anymore. Jellyfish are nasty, and some sting.

    There are usually a lot of jellyfish near the shore after a storm. And in front of him they try to swim away.

    I love jellyfish very much warm water, so there are most of them in the Black Sea towards the end of summer - August, September. Although many indigenous people note their presence in large quantities and in early June, near the shores of some beaches.

    When there are a lot of jellyfish, many residents of the Black Sea try not to visit the beach and wait for the jellyfish to swim away. After all, sometimes you come across individuals that sting painfully. It is unpleasant. Moreover, if you have been bitten painfully by a jellyfish at least once, then from that moment you begin to fear them.

    There are many small jellyfish in the Black Sea, but most often they live in the water column. Previously, mussels were caught in the Black Sea and biological additives were made from them for animals, but unfortunately, production is now closed. After all, from 5 kg you get 100-200 grams useful product, the rest is all water.

    Usually in the second half of August the jellyfish season begins on the Black Sea. Sometimes there are simply unimaginably many of them, and sometimes they hardly bother you. Why does this depend? Yes, it depends on many factors: on how warm the sea is, on how strong the current is in a particular place.

    However, the presence of jellyfish is definitely not a reason to refuse a vacation at this time. Moreover, the end August - beginning September is an amazing, cool time to relax - the water has warmed up, there are fewer vacationers, local fruits and vegetables - you can’t get enough. In addition, jellyfish in the Black Sea are quite harmless. If one of them does bite you, just lubricate the affected area with vinegar and it will quickly go away (I was taught this little trick In Bulgaria).