Jellyfish are the oldest multicellular inhabitants of our planet, appearing more than 650 million years ago. These jelly-like creatures consist of up to 98% water, while most of their body is the stomach, combined with the mouth. Around the oral cavity there are special tentacles-blades, armed with special stinging cells with toxins. With the help of these cells, the jellyfish paralyzes its prey and also defends itself. Jellyfish move by pushing and pushing water through themselves. The effectiveness of this method of movement is facilitated by the shape of the jellyfish - a bell or an umbrella, the contraction of which is carried out by muscle fibers. Despite the fact that jellyfish are able to move, even the largest individuals, reaching a diameter of more than a meter and a weight of several centners, are not able to withstand sea currents and are therefore classified as plankton. They live throughout the planet, inhabiting exclusively salt waters- both surface layers and depths of several kilometers. Jellyfish are adapted to live in both warm tropical waters and subpolar regions. They are predators, feeding on zooplankton, including fish eggs, as well as fry. They themselves are also prey for large fish.

Ctenophore and environmental disaster

Jellyfish of the Black Sea in last decades attract everyone's attention. The fact is that the hypertrophied increase in jellyfish populations has become not only a consequence, but also the cause of a number of radical shifts in the entire living world of the Black Sea. The biomass of jellyfish in the Black Sea varies from year to year; in recent decades it has sometimes reached 90% of the total biomass of living organisms.

Since the 1930s, intensive, exhaustive fishing began in the Black Sea. First, the populations of large predators: dolphins, tuna, mackerel were sharply reduced. In the absence of predators in the 1970s, small fish multiplied en masse, but as a result of overfishing, by the beginning of the 1990s, their numbers fell sharply. The increased food supply, as well as a decrease in the load from predatory fish, led to an explosive growth in jellyfish populations.

An accidental biological invasion had especially catastrophic consequences: along with ballast waters from the Atlantic, the ctenophore Mnemiopsis leidyi was brought to the Black Sea. From a systematic point of view, comb jellies are not jellyfish, but they have a similar appearance and lifestyle. This is a small, light, transparent jellyfish-like creature with the ability to luminesce. In the light it shimmers brightly, at night it gives the sea waves a yellowish luminescent glow. Mnemiopsis is an active predator, feeding on zooplankton, fish eggs and larvae. Its homeland is the part of the Atlantic adjacent to Florida, but thanks to human connivance, since 1987 its range has expanded to the Black, Caspian and even the North and Baltic seas.

The animal turned out to be a universal colonist: this self-fertilizing hermaphrodite develops very quickly, reaching sexual maturity in 12 days; survives in a wide range of environmental conditions, in waters with salinity from 3.4 to 75 ppm, at temperatures from 1.3 to 32 ° C, able to survive in waters heavily polluted by anthropogenic discharges; and most importantly - focused on a wide range of feeds. Mnemiopsis can consume 10 times its own weight per day, and with an abundance of food, it can double in size per day, laying up to 8,000 eggs per day.

In 1987, having found itself in a favorable environment in the Black Sea and having practically encountered no predators (which were so promptly destroyed by man), it began to reproduce intensively, devouring zooplankton (which was in abundance due to declining populations small fish), as well as destroying the eggs and fry of local fish. In just two years, by 1989, the amount of food for fish had decreased by 30 times compared to the period 1978–1988. According to expert calculations, the total biomass of ctenophores in the Black Sea in 1989 was about 1 billion tons (90% of the total biomass of the Black Sea).

Eutrophication of the reservoir occurred, expressed in a sharp increase in the number of small algae, the growth of which was previously restrained by zooplankton populations. The transparency of the water was also greatly reduced by the abundance of mucus - food undigested by the ctenophore, which it secretes in huge quantities. The number of local fish populations has decreased tenfold, with anchovy (“anchovy crisis”), mackerel and sprat especially affected. Losses in the fishing industry amounted to hundreds of millions of dollars. However, at the end of the 1990s, the situation was stabilized by the introduction of another ctenophore into the Black Sea waters - Beroe ovata, whose food is exclusively Mnemiopsis. However, the consequences environmental disaster were largely irreversible.

Jellyfish locales

In addition to ctenophores, two local jellyfish live in the Black Sea. The largest and most beautiful jellyfish of both Black and Mediterranean Sea is Cornerot (Rhizostoma pulmo). This jellyfish is easily recognized by its blue-violet, fleshy, bell-shaped dome and the heavy beard of mouth lobes underneath. The diameter of the dome can reach 70 cm with a jellyfish weighing up to 10 kg.

Jellyfish of the order Cornerotae are distinguished by the fact that they do not have a single central mouth. Its functions are performed by eight long root-like “arms”, which are interconnected by numerous openings into a system of canals. Externally, the “hands” really resemble tree roots, hence the name of the jellyfish - kornerot. These “arms”-blades contain poisonous stinging cells that can burn the skin like boiling water. The diameter of the burn can reach 50 centimeters and take several years to heal. Often, the affected person later develops a persistent allergy to seafood.

Cornerota jellyfish are excellent swimmers. Unlike their relatives, they can move in any direction. Interestingly, the cornet helps fish fry to survive in the sea, hiding under its dome from predators. It itself feeds exclusively on plankton. Due to their “meatiness”, people eat cornetroots - in Japan and Korea they are known as “crystal meat”.

And finally, the fourth species of jellyfish that inhabits the Black Sea is the eared aurelia (Aurelia aurita) - the most numerous and widespread species of jellyfish on Earth. They live in subtropical and tropical latitudes, in seas with any concentration of salt in the water. The body is translucent, pinkish-violet. Quite large, can reach 40 cm in diameter. The dome of Aurelia has the shape of a round flat umbrella, along the edge of which there are numerous thin tentacles hanging down. The tentacles are studded with stinging cells that kill and paralyze small animals. Around the square-shaped mouth opening there are blades with which the aurelia captures and directs food into the mouth. In their shape, they resemble the ears of a hare, hence the name jellyfish. Aurelia feed mainly on zooplankton, sometimes their food is juvenile fish and caviar.

Aurelia eared prefers coastal areas with warm and clean water, but it is not uncommon to encounter this type of jellyfish even far from the shore. Sometimes aurelia form extended dense clusters, which should be avoided to avoid becoming a victim of multiple attacks. This may lead to serious allergic reactions, skin diseases, the appearance of a rash. People with highly sensitive skin can be especially seriously affected. Alone, aurelia do not pose a great danger to humans, but an unprotected body can receive a slight (weaker than nettle) burn from stinging cells.

What to do in case of a burn

If you do get stung by a jellyfish, the first step is to thoroughly rinse the affected area with water to get rid of the poisonous stinging cells. It is not recommended to use fresh water. Then you can wipe the burn area with a dry towel or napkin. If contact took place with your hands, you should not touch your face, especially your eyes, after that. If your eyes are damaged, you should immediately seek qualified medical help.

Next, you can soften the effect of the poison on the skin. To do this, the affected areas of the skin need to be wiped with vinegar, it will slightly reduce the itching and burning. For the same purpose, use a solution of soda, ammonia or strong alcoholic drinks. It is advisable to hide the affected areas from the sun - skin irritated by a jellyfish burn can easily also get a sunburn.

Text: Maxim Kharitonenkov, Candidate of Biological Sciences, Researcher Center for Problems of Ecology and Forest Productivity of the Russian Academy of Sciences, guide of the travel agency "Ruta"

Everyone who has swum in the sea has seen jellyfish at least once. These are extraordinary creatures, as if they came to us from fairy tales. How do they live, so light and airy, because you can see right through them? We want to talk about what jellyfish eat, how their body works and why they are dangerous.

What is a jellyfish made of?

Jellyfish is a very ancient animal, representing the next phase life cycle cnidarians (aquatic multicellular animals) from the subphylum Medusozoa.

Looking at this creature, it seems that it is just water in an incomprehensible shell. This is partly true. The gelatinous body of the creature 98% consists of water, covered with connective tissue similar to our skin. Sensitive bodies are located on its surface, serving as a kind of sensors capable of perceiving environment and its impulses, such as light or vibrations around.

Of the organs that cnidaria have:

• Stomach;
• Intestines;
• Oral opening;
• Eyes (various numbers).

And oral lobes containing a burning substance that is used for defense and food extraction.

The animal moves using its dome-shaped shape. It allows, by contracting the muscles, to throw out bundles of water from under itself, which push the hostess like a jet engine. But, despite this, even the largest individuals cannot resist sea currents and always move with it.

How and what does it eat in the sea?

Jellyfish are coelenterate and invertebrate creatures. This means that they are deprived of some specialized organs, including excretory organs. Food enters through the mouth, is digested here with the help of glandular cells, and the remains are excreted back in the same way, that is, in a vicious circle - through the mouth.

What is included in their diet? This predators, they eat small ones sea ​​creatures :

• Worms;
• Plankton;
• Caviar;
• Crustaceans;
• Sometimes even weaker brothers.

In this they are helped by tentacles equipped with stinging poisonous cells that paralyze the victim. They put food into their mouths.

Different jellyfish have different hunting tactics. Some species pass water through themselves like a filter, leaving what is needed. Others wait for the prey to swim up and grab it.

What do scyphoid jellyfish eat?

Scyphoid- marine organisms from the same type of cnidarians, some representatives of which reach very large sizes. Usually these are the same creatures that are shown in the programs, large, bright and colorful.

In our country scyphoid jellyfish are rare, but three species have been seen:

• Eared;
• Lion's;
• Cornerot.

Some of them were about a kilometer long.

Scyphoids are passive hunters; they wait for the prey to swim up. Any living creature passing through the tentacles activates the work of poisonous cells. A release of toxins occurs, which paralyzes the victim and kills him.

The main food resource of scyphoids is zooplankton - small crustaceans, animal larvae, and fish eggs.

Is it possible to keep them in an aquarium and what to feed them?

Until recently this would not have been possible. Animals died in ordinary aquariums. But progress does not stand still. Carousel-type aquariums or “jellyfish tanks” appeared on the market. The principle of their operation is based on the fact that water does not stand still, but constantly rotates. In such a device, this creature has the ability to hang on the stream, not sink to the bottom and not float up.

The main thing that breeders should know about jellyfish is:

1. That the flow speed should be comfortable for animals so that they do not sink or float;
2. That there should be no aeration here. Air bubbles can harm the inhabitants; they accumulate under the dome body and are thrown upward.

You need to feed your pets a variety of foods. For this purpose, special vitamin supplements are used. You can take minced seafood from the store and pour it into the water.

Why are jellyfish dangerous?

Everyone knows that some species can harm humans. While swimming, if you touch a spider, you can get a severe burn and more.

In our country there are also such, although in smaller quantities than in other seas:

• Cornerot- the largest representative living in the Black Sea. Its lacy lobes are abundantly supplied with stinging cells. They do not pose a great danger to humans. Only people who are sensitive to touch can develop burns similar to a nettle sting. This is why it is sometimes called “sea nettle”;
• Hairy cyanea- found in Pacific Ocean. Its bell-shaped body has a variety of colors with a predominance of red tones. The long tentacles are a dense network densely packed with poisonous cells. Their toxins can quickly kill small fish. They are not so dangerous for humans, but their bite is noticeable on the skin and can cause allergies;
• Gonionema - found in the Sea of ​​Japan. A small inhabitant, through whose transparent umbrella a cross pattern is visible. Damage to its cells is not fatal, but very painful. There are cases when people could not do without the help of doctors. This is due to the effect of the poison on nervous system. The person may lose sensation in their limbs or have trouble breathing.

These are all representatives of stingrays that can cause harm in one way or another. The rest are dangerous only for the inhabitants of the sea.

How to treat bites?

But, if this does happen and you are stung by a jellyfish, proceed as follows:

• Wash away toxic substances with water;
• Do not scratch or touch the bite site;
• Apply cold water or make a lotion. Apple cider vinegar or ammonia are suitable for this;
• Take antihistamines;
• Apply insect bite repellent or “Fenistil-gel”, “Psilo-balm” to the wound;
• Drink plenty of fluids;
• Be sure to consult a doctor.

Yes, the poisons of animals living in our seas are not lethal. But be careful, they can cause severe allergies. Monitor the victim closely for the first 24 hours, especially if it is a child.

Surprisingly, these beautiful creatures are real predators. Now, knowing what jellyfish eat, you can safely tell your friends about it. This animal is not just a bag of water, as some people imagine them to be. It is an organism that eats other animals. And sometimes even their own kind.

Video about feeding jellyfish

In this video, oceanologist Roman Vorotnikov will show how jellyfish feed in an aquarium:

On Black Sea coast There are two types of jellyfish: Cornerot and Aurelia. There is also a jellyfish-like mnemiopsis, belonging to the species of ctenophores, that shimmers beautifully in the light. bright colors. Not all of them are dangerous to humans. Mostly jellyfish are found off the coast, delighting small children. Only blue cornermouths can burn with their tentacles.

There are unusually beautiful jellyfish. These marine inhabitants originated hundreds of millions of years ago; they are on the list of the most ancient inhabitants of the planet. Since then, their characteristics have not changed.

Jellyfish consist of a jelly-like mass that is 98% water. They were included in the animal world only because of the presence of a digestive system and muscle fibers. Jellyfish do not move against the current, moving with the current due to muscle contractions.
Vacationers sometimes call coastal jellyfish plankton. But unlike the latter, they can ruin a pleasant vacation.
Most of the jellyfish are concentrated in Yevpatoria, on the Odessa coast and near the strait connecting the Black and Azov Seas.
About 2,000 species of jellyfish are known, but only three are found in the Black Sea.

Photos

Aurelia

The most numerous species of jellyfish is no more than 30 centimeters in diameter. During the summer period when their numbers increase, the water is teeming with them. Despite the not very pleasant feeling of contact with a jellyfish, they do not pose any particular danger.

Mnemiopsis

A glowing, jellyfish-like ctenophore without tentacles. They sailed to us from the shores of the USA. They are very voracious and, at the slightest opportunity, eat fish larvae and eggs. Moreover, they can go without food for about two weeks.

Cornerot

Dangerous poisonous species jellyfish living in the Black Sea. The active period is in late summer and early autumn. Cornerots of blue color, and their tentacles burn strongly.

Unlike many eastern countries, local residents do not eat jellyfish.

Video

Photo & video - S. Pyatibratov

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Holidays on the Black Sea coast are an excellent alternative to foreign resorts - soft southern climate, a considerable amount of entertainment and high level services have made Crimea one of the popular destinations for tourism.

The abundance of architectural monuments and simply picturesque places on the peninsula allows you not only to mindlessly relax on the beach, but also to spend time usefully by visiting numerous excursions. Having visited Crimea, you will not miss it - this castle attracts hundreds of visitors every day, and you will get a lot of positive emotions from the excursion.

Dangerous inhabitants of the Black Sea

The Black Sea coast gives vacationers not only a comfortable climate - the local fauna is friendly and does not pose a danger to humans. Even a meeting with predatory sea inhabitants is fraught with only mild irritation, however, allergy sufferers should still be wary of certain types of marine animals.

1. Stingray stingray. You should not try to grab it by the tail - at its end there is a sharp and hard thorn that can inflict a deep, although not fatal, wound.
2. Sea Dragon. This fish prefers to burrow into the mud at the bottom of the sea and wait for its prey there. Its needles contain poison that causes irritation but is not dangerous to humans.
3. A meeting with a scorpionfish can interrupt your vacation for 2-3 days. Its venom causes fever and general malaise. Fortunately, treatment exists and can quickly get the unwary diver back on his feet.

Jellyfish occupy a separate position in the Black Sea fauna - although they do not pose a danger to humans, meeting them can cost you very unpleasant memories. The main weapon of all Black Sea jellyfish is stinging cells containing a special toxin. When it comes into contact with the mucous membrane or skin of a person, it causes burns comparable to nettles.

Jellyfish of the Black Sea, their photos and descriptions

There are 3 main types of jellyfish found on the Black Sea coast:

The largest concentration of jellyfish occurs in the second half of summer - while relaxing at this time, you are likely to encounter this marine inhabitant. The blue jellyfish feeds on small fish, worms, and miniature crustaceans. It uses its poison to paralyze the victim, after which it begins to eat.

Are there any benefits from jellyfish?

Thanks to jellyfish, the natural balance of marine fauna is maintained - they eat eggs and small crustaceans, preventing the population from growing.

Such jellyfish serve as food for some species of large fish and sea turtles. Cookbooks contain many recipes for cooking jellyfish, because they are a source of pure protein, and are very popular in some countries, despite the special structure of their body.

Those who want to visit in the second half of summer are advised to stock up on first aid supplies for burns in advance. It is at this time that the number of jellyfish in the sea and on the shore is thousands of times higher total number vacationers, and sometimes a diver inevitably returns to shore with a burn.

Fortunately, the poison contained in stinging cells is not dangerous to humans, but can cause some discomfort. After meeting with a jellyfish, you must thoroughly rinse the bite site with water and apply a compress of vinegar, soda solution or strong alcohol. These compositions will quickly dissolve the poisonous stings remaining in the skin, which promotes recovery after the bite.

Only people with weakened immune systems and allergies are at risk - for them, a jellyfish burn can cause serious complications and they are advised to short term consult a specialist.

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Hello, dear fans of holidays in Crimea!

What jellyfish can be found in the Black Sea? Description of sea inhabitants, their photographs and videos. What should you be wary of while holidaying in Crimea?

What jellyfish live in the Black Sea

Extraordinarily beautiful jellyfish in the Black Sea and in all other corners of the planet are the most ancient inhabitants of the Earth. Their age is estimated at hundreds of millions of years, and appearance and the simple structure of the body have remained unchanged since that time.

The composition of jellyfish is about 98% water, collected in a jelly-like mass. Only the presence of muscle fibers and the simplest digestive system allow them to be classified as an animal organism. Jellyfish move slowly due to muscle contraction, but cannot swim against the current. The inability to resist currents has led to the fact that jellyfish on the Black Sea coast are contemptuously, but quite scientifically, called plankton. But how can this plankton ruin a beach holiday!

Science knows more than two thousand species of jellyfish. There are only three of them in the Black Sea: Aurelia, Mnemiopsis and Cornerot. According to last year’s data, there are especially many jellyfish found near Evpatoria, Odessa and in the region Kerch Strait, where Black and Sea of ​​Azov. Analyze to implement your plans for this summer. There is also an abnormal number of jellyfish on the western coast of the peninsula: in the area of ​​​​Karnikitsky Bay and near the village of Chernomorsky.

Aurelia aurita- the most numerous species of jellyfish in the waters of the Black Sea. The long-eared aurelia, as local fishermen call it, usually does not exceed 30 cm in diameter. With a seasonal increase in the number of this species, sea water is literally a compote of translucent amorphous bodies. This is quite unpleasant, but completely painless for humans. This number of aurelia is explained by the fact that they can easily withstand the temperature sea ​​water up to 30°C. Photo below

Mnemiopsis leidyi- species without tentacles. They are unable to sting, but they glow very beautifully in the dark. These are alien jellyfish, and not the indigenous inhabitants of the Black Sea. They came here from the shores of the United States. Their incredible gluttony poses a serious threat to industrial fishing. After all, Mnemiopsis does not stop eating fish eggs even when its stomach is full. It simply pushes out excess food in the form of a ball of mucus and further destroys eggs and plankton. At the same time, it is easy to go without food for up to two weeks.

The most dangerous species of jellyfish in the Black Sea for humans

The Black Sea jellyfish that constantly inhabit our shores (photos of the most interesting specimens can be seen here) do not pose any serious threat to people. But, according to the deputy director of the Institute of Biology, Alexander Boltachev, cornermouths ( Rhizostoma pulmo) - the most dangerous poisonous jellyfish of the Black Sea (photo at the top of the page) appear in abundance off the coast in August and September.

Large blue beauties should be avoided because their tentacles sting. Following a strictly scientific approach, these are not even tentacles, but elongated oral growths. If you catch a cornet jellyfish, you must hold it strictly by top part amorphous body, without touching the processes under any circumstances. Jellyfish in the Black Sea are especially dangerous for the mucous membrane of the human eye. Be sure to bring first aid supplies with you when planning