Are jellyfish dangerous in the Black Sea? What jellyfish are found in the Black Sea.

29.08.2015

Compared to the Mediterranean, the Black Sea has less salinity of water, in winter some of which is covered with ice, and in summer at a depth of 60-80 meters the temperature does not exceed 7 degrees. In the depths of the Black Sea there is an accumulation of life-threatening hydrogen sulfide gas. Therefore, its relatively poor organic life is concentrated on continental shallows and in the surface layer open sea to a depth of 160 meters. But even here there are animals that can cause trouble for a person upon meeting and direct contact. These include two species of scyphoid coelenterates common in the Black Sea.

Although this permanent inhabitant of warm coastal waters this sea does not pose a threat to human life and health, in the absence of other representatives, it is the most dangerous jellyfish Black Sea. Rhizostoma is also the largest (of the three species living in it) jellyfish of this reservoir. Cornerot jellyfish can weigh up to 10 kg and reach 50-60 cm in length.

In an adult animal of this species, the mouth is completely overgrown, and its role is played by numerous openings on the oral lobes, equipped with processes. For external resemblance Physiologically performing the role of the mouth of processes with the roots of plants, the family got its name. The hemispherical white-transparent umbrella of the rhizostomy along the edge contains a bright border of blue, blue or purple.

Its lacy “legs” contain stinging cells containing a rather strong poison - rhizostomin. It is capable of paralyzing shrimp, fish and other small animals, although it feeds exclusively on plankton. Contact with this lace of skin sensitive person will give the sensation of touching a hot iron and may cause irritation similar to nettles.

Therefore, rhizostomy is also called nettle, stinging nettle or zhigalka. Unlike smaller jellyfish, which move passively, carried by water, cornermouths are capable of active jet propulsion. Their umbrella constantly contracts, pushing out water that moves the body of the rhizostomy. More often it swims on its side, but can quickly escape pursuit or hide into the depths with its umbrella forward.

This is the most common scyphojellyfish in the World Ocean. She lives in almost all warm seas and oceans, and is even found in Arctic waters. In some years there is so much of it that you have to swim not in water, but in the amorphous transparent bodies of these animals. Fortunately it is quite safe. Their stinging cells are less strong than those of the rhizostomy.

Just don’t let her mouth lobes touch the delicate skin of her lips or the mucous membrane of her eyes. Aurelia eared (common jellyfish) is very attractive in appearance. Its dome can reach 40 centimeters in diameter. It is transparent bluish or violet-pink in color. Through the layers, which are 98% water, you can see the insides of the animal. The four horseshoe-shaped “decorations” characteristic of Aurelia are its gonads.

You can also see its internal cavity - the stomach. The oral opening of the aurelia is located on the underside of the dome; four long oral lobes extend from it, which resemble appearance donkey ears, for which it received its second name - eared. Along the edge of the aurita umbrella there are numerous (empty inside) tentacles. They serve as sensory organs for the jellyfish.

They pick up ultrasounds and transmit signals to the oral lobes, which are already executive organs - they drive prey into the mouth opening, capture, and paralyze it with the help of stinging cells. The animal feeds on small planktonic and benthic organisms. Contact of stinging cells with the skin of a person's lips or eyes can cause irritation. The remaining areas of the skin will not be affected by the venom of this jellyfish; it is too weak for that.

Most animals, in a hopeless situation for them, simply defend themselves from humans. When you pick up an Aurelia or Cornerot, don’t expect them to be happy about it. In fear, they will use all their methods of self-defense. If you don't want to be stung or have an allergic reaction, don't touch these animals. It is not animals that are dangerous to humans, but humans that are dangerous to them.

Dangerous jellyfish of the Black Sea [VIDEO]

Jellyfish are the oldest creatures on our planet Earth. These creatures have not changed for more than 650 million years and inhabit only salty bodies of water. Interestingly, jellyfish have a very simple body structure: a stomach and a mouth. The jellyfish moves thanks to stomach contractions. It takes in water and pushes it out, which is how it moves.

There are many stinging jellyfish, but only three species are found in the Black Sea.

Rhizostoma - cornero t is the most common jellyfish. Adults grow up to 50 cm in diameter. It is easy to recognize this type of jellyfish. It has a slightly purple border around the white dome. Long roots with thickenings extend from its body. This is where the stinging cells are located, which contain toxins that cause burns. The effect of its poison wears off after a couple of days and resembles the effect of nettle. These jellyfish have amazing weather sensitivity. Anticipating bad weather or the storm corner goes to depth.

Aurelia- large jellyfish. White, translucent with a hint of pink or purple. Four circles are clearly visible on its dome. Aurelia lives in the coastal part of the sea, as it prefers more warm water.

Mnemiopsis- Not big jellyfish, the diameter of its dome is approximately 10 cm. It has no tentacles and glows in the dark. This little jellyfish is very voracious. She eats constantly because she does not have a satiety reflex. This little jellyfish is not native to the Black Sea. It was brought from the coastal waters of America.

All jellyfish are passive creatures. Some species live in mass aggregations, while some live solitary. They feed on small fish sea ​​worms, small algae, eggs. Can self-reproduce. They do not have a settled lifestyle and move at the will of the wind, waves and currents.

In July and August, rarely in September, when the water warms up to its maximum, you can observe large number jellyfish near the shore. During this comfortable time for jellyfish, they actively reproduce.

Should we be afraid of Black Sea jellyfish?

The poison of jellyfish living in the Black Sea is not dangerous. Toxins from stinging cells cause mild but unpleasant burns. Cases of strong reactions of people to contact with a jellyfish, even to the point of loss of consciousness, have been recorded. Scientists constantly monitor jellyfish populations and conduct research papers. Toxicologists do not give a clear answer about the danger of stinging jellyfish. But it’s better not to tempt fate and not touch these not fully studied inhabitants of the sea. Use caution and teach children about jellyfish. Stinging cells are found in the tentacles and branches of jellyfish. Avoid contact with them. Be alert and prepared.

We wish you a great holiday!

In the section on the question: What determines the number of jellyfish in the sea? given by the author Neuropathologist the best answer is As the water temperature rises to 23-25 ​​degrees, the number of jellyfish in the sea increases.
It has long been noticed that jellyfish, a few hours before the start of a storm, move away from the shores into the sea or lie on the bottom. Studying the reasons for this precaution allowed technicians to design a sensitive sensor that warns a person of an impending storm.
In summer and autumn there are a lot of jellyfish off the coast of Crimea. They clog fishing nets, disturb those swimming in the sea, and are washed ashore en masse by the waves. The Russians called them live growth, sea lard, the Chinese - sea moons, the Japanese and Arabs - sea lanterns.
There are two types of jellyfish: eared jellyfish aurelia and cornerot (pilema, rhizostomy, pulmo). Aurelia has a flattened, slightly pinkish or slightly purple umbrella, with a diameter of up to 20 cm. Cornerot has a denser and more elastic body than Aurelia, and it is larger in size. The umbrella is milky white. The “weapons” are the same as those of Aurelia - stinging cells. The burn they cause is somewhat reminiscent of a nettle burn. Hence three more Russian names for jellyfish: sea nettle, zhguchka, zhigalka. For jellyfish victims and enemies, the effect of burns is very noticeable; for humans, if the burned surface is large, it is also sensitive. By the way, it should be mentioned that in Australia, scientists have created an anti-burn vaccine from jellyfish and are already using it, that is, treating like with like.
Jellyfish move by frequent energetic contractions of their umbrellas, which, despite their jelly-like appearance, are equipped with strong annular muscles. Unlike Aurelia, Rhizostoma is an inhabitant of great depths; it rarely appears on the surface of the sea and, if it is noticed, it immediately moves deeper into the depths with pulsating movements. The role of jellyfish in the life of marine biocenoses is more than modest. By destroying a large amount of plankton, jellyfish partially deprive other contenders for it, but on the other hand, the jellyfish nurture small fish and fry. Under their hoods, for example, juvenile horse mackerel finds refuge from predators.

Black Sea jellyfish are the oldest jelly-like organisms without a skeleton or tissue base. They are found only in salt water of varying saturation, they move chaotically, unconsciously. The existence of jellyfish cannot be attributed to any of the evolving categories. In the 650 million years since their appearance, these transparent gelatinous animals have not changed one iota.

Anatomy

The body of a jellyfish is extremely primitive: from internal organs it has only a stomach, which is connected to the mouth. There is no hole for removing waste; the animal also pushes out all waste food through the mouth. The stomach of most species of jellyfish is used for movement in space. It works on the principle of a jet nozzle, contracting, pushing out the collected water and thereby creating thrust, due to which movement occurs.

Varieties

In total, thousands of species of jellyfish live in the Earth's reservoirs, seas and oceans. Some live in colonies in the form of huge clusters, slowly migrating with the current or under the influence of the wind. Others are, as a rule, quite large specimens, live separately, hunt alone, but do not have housing. Jellyfish do not have a settling reflex, and they never stay in one place.

Stinging jellyfish in the Black Sea are not numerous, there are only three species: Cornerot, Aurelia and Mnemiopsis. These animals have been well studied, but belong to the category of individuals that are under constant observation by scientists.

Population distribution

The largest Black Sea jellyfish is the rhizostoma pulmo. The diameter of its round body can reach half a meter. Cornerot is a well-recognized animal; its difference from other species is the absence of tentacles. Instead, massive branches up to a meter long extend from the dome. Each has spongy thickenings.

How is the corner mouth constructed?

The dome, or umbrella, of a jellyfish is milky white in color, round, spherical in shape, with a purple fringed border running along the edge. Hanging from under the dome are eight fleshy roots with soft growths in which poisonous stinging threads are hidden. When touched by someone else, the jellyfish shoots out stinging arrows and can deliver discomfort, similar to nettle burn. The poison is weak, its effect wears off within a few days.

Cornerot feeds on small fish, sea worms, and small crustaceans. It paralyzes its prey with poison and then eats it. This type of jellyfish is the largest population in the Black Sea. And although there is no benefit from these animals, it is the cornet that has unique ability, for which Black Sea fishermen value it. This jellyfish is a living barometer; it is sensitive to weather changes; on the eve of a storm, it moves away from the shore and goes into the depths.

However, not all marine protozoa have such abilities. Other jellyfish of the Black Sea, Aurelia and Mnemiopsis, do not feel the approach of bad weather, remain on the surface and die in the thousands. These two species are less numerous, but their numbers are also significant. Habitat - mainly in shallow water, along the coast of Crimea, around the city of Sudak, the village of Planerskoye and all the way to Kerch. Both species are capable of movement, but their migration is chaotic.

Black Sea jellyfish have long been studied by scientists for their migration. For for many years observations, only one conclusion was made: there is no pattern in the movements of gelatinous creatures. They are completely left to the elements and resemble autumn leaves: wherever the wind blows, they float. Scientists tried to draw a logical chain, linking the migration of jellyfish with prevailing winds. However, the jellyfish of the Black Sea did not live up to expectations even in this matter; they simply never strive anywhere. If there is no wind, they stand still; if the wind blows, they move.

Aurelia

Another large jellyfish that lives in the Black Sea is the Aurelia. The diameter of its umbrella, or dome, is about forty centimeters, the body is translucent, usually colorless, but sometimes acquires a pink, blue or purple tint. At the top of the dome four circles are visible, arranged symmetrically. These are the gonads. Poisonous jellyfish of the Black Sea are unisexual creatures; they fertilize themselves when it is time to reproduce.

Aurelia, or sherikh, as it is also called by fishermen who fish in the Black Sea, feeds on small crustaceans, larvae, and diatoms. Having caught the prey, the jellyfish lulls it with poison and, after the victim is immobilized, slowly eats it. Aurelia lives in coastal strip, in shallow water, does not swim far into the sea and does not dive to depth. This format of existence is explained by the fact that the jellyfish is afraid of the cold, its living space is limited to warm water.

At the same time, this species is very tenacious. Jellyfish are thermophilic, but can withstand sub-zero temperatures without dying. Such abilities are observed in many invertebrate animals; some tolerate cooling while moving, others fall into suspended animation.

Mnemiopsis

The jellyfish is relatively small in size, up to ten centimeters, and lacks tentacles and stings. It is distinguished by the ability of biological luminescence, that is, it glows in the dark. Once born, Mnemiopsis develops quickly, sexual maturity of both male and female individuals occurs no later than two weeks from the date of birth. The process of fertilization is not fundamental; the jellyfish is capable of self-reproduction. The embryo is formed within twenty hours.

Mnemiopsis feeds only on zooplankton, sometimes eating the eggs of small fish, sprat, sprat, and capelin. The jellyfish is distinguished by the absence of a satiety reflex; it always eats. If the gastric space is completely filled, the excess is discarded and the process continues. At the same time, when complete absence feeding, a jellyfish can live from two to three weeks.

Mnemiopsis was introduced into the Black Sea from the eastern shores of America by chance, in the holds of ships plying along trade routes. Its appearance in the Black Sea caused significant damage to fishing. Today, measures are being taken to reduce the population of this jellyfish.

Should you be wary of gelatinous organisms?

Whether jellyfish in the Black Sea are dangerous or whether there is no reason for concern is a question that has been studied for a long time. There is still no definite answer. There is, of course, poison in the stinging tentacles of Black Sea jellyfish, but it is weak and can cause a sting like nettle, but no more. However, there were cases when people who suffered from contact with a jellyfish near the coast of Crimea lost consciousness from strong toxic poisoning. In such a situation, the answer to the question of whether jellyfish are dangerous in the Black Sea should be in the affirmative. Therefore, the conclusions of toxicology scientists are still vague, research continues.

So, the question is “Jellyfish in the Black Sea are dangerous or not?” remains open for now. In places where they gather, it is recommended to be careful and touch their umbrellas, and especially their tentacles, as little as possible. In addition, every bather must know which jellyfish in the Black Sea sting and which are absolutely harmless. This information will help you avoid being bitten by a harmless animal unless provoked.

When do jellyfish appear in the Black Sea?

Invertebrates, especially marine ones, have their own " holiday season"When they are most comfortable in their native element, it is warm and there is a lot of food. For Black Sea jellyfish, these are three months of the year: July, August and September. At this time, they actively reproduce, swim to the best of their ability, and humans should not disturb harmless creatures, it is better to let them live their lives. The time when jellyfish appear in the Black Sea is not precisely determined, the time is different every year, but approximately it is the end of June - the beginning of July.

Vacationers were seriously scared: on the Sea of ​​Azov this year there appeared giant jellyfish, which no one has observed for many years. What to do if one of them stings you.

WHERE DID THEY COME FROM?
Cornerot jellyfish have appeared at the resorts of Azov - the most large jellyfish Black and Mediterranean seas, which can weigh up to 10 kg, and their diameter reaches 50-60 cm.

Ecologists explain: jellyfish have returned to the Sea of ​​Azov due to changes in the composition of the water. In the 1970-1980s, the salinity of the sea was 14 ppm, in the 1990s it dropped to 10, and during the same period, jellyfish disappeared from there. Now the water is approaching the levels of 40 years ago, so they are returning marine inhabitants for whom this environment is favorable.

WHAT ARE JELLYFISHES DANGEROUS?
The danger of this type of jellyfish is in its tentacles. They are poisonous. Upon contact with them, a person may experience allergic reaction, and the consequences are like a nettle burn. Usually the burn goes away within a few hours (in extreme cases, after two days).

In most cases, jellyfish stings do not pose any threat to human life. Exception - " sea ​​wasp", after contact with which a special serum is needed.

BITE SYMPTOMS:

- sharp pain that may intensify;

- rash (small red rashes that can later fill with fluid);

- blisters (sometimes with bruising);

— intoxication (if the poison has spread throughout the body, you may feel nausea, malaise, weakness);

- allergic reaction: pain, burning sensation and red spot.

WHAT TO DO IF A JELLYFISH STITE?

1 Wash the bite area with salt water.

2 Remove any remaining jellyfish (you can use a hard terry towel or a credit card, but most importantly, do not do this with your bare hands).

3 Treat the skin with chlorhexidine.

4 If burning, itching or swelling occurs, take antihistamines.

5 The burn site can be lubricated with anti-inflammatory gel. If you don't have one on hand, use an ice compress.

6 Antihistamine ointment or gel can be replaced by shaving foam (thanks to menthol, the skin will become less sensitive and irritation will go away faster).

7 Drink more water.

8 If you feel unwell or have allergy symptoms, contact your doctor immediately.

WHAT NOT TO DO?

Firstly, never remove the remains of a jellyfish with your hands, use a foreign object for this.

Secondly, do not rub your eyes with your hands after a jellyfish bite.

Thirdly, do not wash the burn area fresh water(in unsalted water, “poisonous” cells are instantly destroyed and the remains of the poison can get under the skin).

IMPORTANT! Do not make lotions from vinegar and alcohol. From such lotions the poison spreads very quickly.