Aurelia jellyfish is the most common jellyfish, well known to everyone who has been to the sea, is an eared jellyfish, or aurelia (Aurelia aurita), living in the Black, White, Barents, Baltic, Japanese and Bering Seas.
Aurelia also enters the arctic zones and tropical seas.
This jellyfish is a bad swimmer - shortening its umbrella, it can only slowly rise, and frozen motionless - quietly dive into the depths. Aurelius are often found in large numbers on the seashore after a storm.
Aurelia flat umbrella can reach 40 centimeters in diameter. It is completely transparent, since it is based on a non-cellular substance, 98% consisting of water. Therefore, the specific gravity of the animal's body is close to the specific gravity of water, which greatly facilitates swimming. The tentacles of Aurelia are located along the edge of the umbrella, they are small, but extremely mobile and seated with numerous stinging cells, the device of which resembles that of the hydra. Along the edges of the quadrangular mouth, located in the middle of the bell, hang four scalloped mouth lobes, which are also very mobile. The prey struck with the help of stinging cells, mainly small crustaceans, due to the contraction of the oral lobes, also covered with stinging cells, is pulled up to the mouth opening and captured by it.
Reproduction of aurelia
The eared jellyfish is a dioecious animal. The testicles of males are milky white and are clearly visible in the form of semicircles in the body of a jellyfish. The ovaries of the females are red or purple and also show through the bell. By the color of the gonads, you can determine the sex of the jellyfish by eye. Aurelia breed once and then die. Unlike most scyphoid jellyfish, Aurelia take care of their offspring.
In a jellyfish hanging in the water, the oral lobes are lowered, so the eggs emerging from the mouth opening inevitably end up in the gutters and, moving along them, fall into the pockets where they are fertilized and developed. The fertilized egg begins to split: first in two, then each cell is also divided into two, and so on. The result is a single-layer multicellular ball. Part of the cells of the ball sinks inward, like a rubber ball can be squeezed, resulting in a two-layer embryo. The outer layer of the embryo's cells is covered with many cilia, with the help of which it gains the ability to swim. From this moment, the embryo becomes a larva, which is called a planula. She swims in the water for some time, and then settles to the bottom, attaching to it with her front end. Soon, a mouth erupts at the posterior (upper) end of the planula and a corolla of tentacles is formed. Planula turns into a polyp, very similar to a hydra.
Over time, the polyp begins to divide transverse constrictions. Crashing into his body, they turn the polyp into a kind of stack of plates superimposed on each other. Such discs-plates are young jellyfish, which go on their own swimming. Thus, asexual reproduction of polyps occurs; they are not capable of sexual reproduction. As already mentioned, only jellyfish reproduce sexually.
Jellyfish food
This jellyfish is used as food in China and Japan, for which even a special fishery is organized. Large specimens of Aurelia are mined for salting. In the extracted jellyfish, the oral lobes are separated and the umbrella is washed until the digestive canals are completely cleaned. Only the non-cellular substance that makes up the umbrella enters further processing. The Chinese call the meat of jellyfish "crystal". Salted jellyfish are added to salads, eaten boiled and fried with various seasonings.
For humans, the stinging cells of the eared jellyfish do not pose a danger, unlike those of the Cornerot jellyfish that lives in the Azov and Black Seas. Cornerot does not have tentacles, and catches prey with the help of highly branched oral lobes, the ends of which look like root-like outgrowths. The stinging cells located on these outgrowths contain a toxic substance - rhizostomine, which causes rather painful burns. Cornerot differs from Aurelia by a bright blue or purple border around the edge of the umbrella. Large specimens of this jellyfish reach 50 centimeters in diameter.
Aurelia jellyfish is a species of marine life that is very interesting and mysterious. Therefore, they are often kept in aquariums. This article contains information about who the aurelia jellyfish is: description, features of the content, reproduction of this species.
general description
In Aurelia, the umbrella is flat and can reach 40 cm in diameter. Since it is based on a non-cellular substance (it consists of 98% water), it is completely transparent. This quality also determines that the weight of these animals is close to the weight of water, which greatly facilitates swimming.
It should be noted that the Aurelia jellyfish has a very interesting structure. So, along the edge of her umbrella there are tentacles - small, but mobile. They are very densely seated with a huge number of stinging cells.
This jellyfish has a quadrangular mouth, has 4 movable blades along the edges. Their contraction (they are covered also makes it possible to pull the prey to the mouth and securely capture it.
Issues of keeping jellyfish differ in some specifics. Initially, it was in aquariums. For jellyfish, special containers are needed that provide a circular smooth flow. This allows the animals to move freely without fear of any collision. This is important because the Aurelia, or eared jellyfish, has a very delicate and soft body that is easily damaged.
It is necessary to ensure the correct flow rate, which should allow the animals to “soar” without problems in the water column. Only in this case, there should be no danger of harm to their bodies.
The specificity also lies in the fact that the use of aeration is absolutely excluded for jellyfish in aquariums. This is due to the fact that air bubbles can be under the dome of the animal, get stuck there and then pierce it, which is very dangerous and can lead to the death of the jellyfish.
They do not need special lighting either, mostly simple lighting is enough.
Also note that there is no need for water filtration. As a rule, only regular water changes are sufficient to ensure that its quality always remains at the proper level. If there is no desire to constantly update the water, you can also start installing a life support system. At the same time, it is important to take proper care of the protection of animals. Because they can be pulled into the intake devices.
In addition, it must be borne in mind that the Aurelia jellyfish must live in a fairly spacious aquarium, since it needs the ability to freely extend its tentacles to their full length.
Feeding
How are jellyfish fed? They are great with a mixture that consists of brine shrimp, phytoplankton, heavily crushed crustaceans and seafood. Although at the moment there are various ready-made foods on sale that Aurelia (eared jellyfish) can also eat. But there is one feature. If the animals do not like the food at all, they can start eating the rest of the jellyfish.
reproduction
Aurelia jellyfish is dioecious. So, the testes in males are milky white, they are perfectly visible: these are small half-rings in the body of the animal. Females have purple or red ovaries, which are also visible in the light. Therefore, by coloring, you can understand what gender the jellyfish is. Aurelias breed only once in their life, and then die. Their main distinguishing feature is the manifestation of concern for their own offspring (which is not typical of other species).
It is worth noting that the fertilization of eggs, as well as their further development, takes place in special pockets. Eggs enter them through the gutters from the mouth opening. After fertilization, the egg divides into 2 parts, each of which is further divided in half, and so on. Due to this, a single-layer multicellular ball is formed.
Some of the cells of this ball gets inside, which can be compared with pressing a rubber ball. Because of this, a two-layer embryo appears.
He can swim, thanks to the large number of cilia that are located on his outer part. The embryo then becomes a larva, which is called a planula. For some time it just floats, and then falls to the bottom. It is attached with its front end to the bottom. Quite quickly, the back end of the planula is transformed: a mouth appears in this place, and tentacles are also formed. And it becomes a polyp, from which small jellyfish are subsequently formed.
Aurelia jellyfish is often used in medicine. Laxatives and diuretics were produced from it in the Middle Ages. And today, from the poison that is contained in the tentacles of animals, they develop means to regulate pressure and treat various pulmonary diseases.
Farmers in the Caribbean use physalium poison as a poison for rodents.
Jellyfish allow you to effectively deal with stress. They are bred in Japan in special aquariums. Slow, smooth movements of animals calm people down, while keeping them is very expensive and troublesome.
Phosphors isolated from jellyfish are used for biochemical analysis. Their genes were transplanted into various animals, for example, rodents, due to which biologists were able to see with their own eyes processes that were previously inaccessible. Because of this action, the rodents began to grow green hair.
Some of the jellyfish are caught off the coast of China, where their tentacles are removed, while the carcasses are kept in a marinade, due to which the animal turns into a cake of thin, delicate, translucent cartilage. In the form of such cakes, animals are taken to Japan, where they are carefully selected for quality, color and size and used in cooking. So, for one salad, the jellyfish is cut into small strips 3 mm wide, they are mixed with herbs, poached vegetables, and then poured with sauce.
Robot jellyfish also appeared there. They, unlike real animals, not only swim beautifully and slowly, but can also “dance” if the owner wishes to the music.
Conclusion
Despite the fact that the Aurelia jellyfish is very common, it cannot be called completely ordinary. In principle, these are very curious creatures, therefore, observing them and keeping them will be very exciting.
Titles: common jellyfish, aurelia eared, eared jellyfish, moon jellyfish.
Area: Pacific, Indian and Atlantic Oceans.
Description: The common jellyfish (Aurelia eared) is easily identified by its four horseshoe-shaped gonads. The body is in the form of a flat umbrella, gelatinous, 97.8-98.2% consists of water. Along the edges of the umbrella are numerous short hollow tentacles and eight marginal bodies (ropalia). Ropals are the sense organs of the jellyfish and determine its position in the water and the rhythm of the contractions of the umbrella. Four thickened mouth arms, each with a central furrow flanked by more diluted rolled lips. Capturing infrasounds, ropalia warn the jellyfish about the approach of a storm and allow it to move away from it. The body is two-layered (consists of two layers of cells - ectoderm and endoderm), with a well-defined gelatinous mesoglea. The mouth is located in the middle of the underside of the body, it leads into the pharynx, from which the intestinal cavity begins. Undigested residues are removed through the mouth. The nervous system of the jellyfish is more developed than that of polyps. In addition to the nerve plexus, most developed in the tentacles and on the underside of the umbrella, two nerve rings run along its edge. Sex glands are located near the stomach or radial canals.
Color: the umbrella is colorless, and the "arms" and gonads are lilac, purple, reddish, pink or yellowish.
Size: umbrella diameter 5-40 cm.
Habitat: near the coast - warm and tropical waters. Tolerates a wide range of temperatures (from -6 to 31 "C) and salinity (from 6 ppm). The optimum temperature is 9-19" C.
Enemies: moon fish, Pacific jellyfish, sea turtles, birds.
Food/food: digestion intra- and extracellular. The common jellyfish captures its prey with its tentacles. It preys on planktonic crustaceans, aquatic insect larvae, fish fry, hydromedusas, ctenophores, copepods, rotifers, nematodes, young polychaetes, protozoa, diatoms.
Behavior: moves in the water according to the reactive principle, pushing water out of the body cavities. The jellyfish floats horizontally in the water column.
Social structure: single organism.
Reproduction: an ordinary jellyfish reproduces sexually. Jellyfish with purple or pink gonads are males, and with yellow gonads they are females. Male reproductive products are released through the mouth into the water, after which they enter the body of the female, where fertilization occurs. The egg develops into a mobile larva - planula, which attaches to underwater objects and there turns into a single polyp. The polyp subsequently proceeds to asexual reproduction. It breaks up into several disks that turn into jellyfish. So in jellyfish there is an alternation of generations: asexual (polyp) and sexual (jellyfish). The life cycle is dominated by the jellyfish form, while the polyp is a short-lived form of existence.
Season/breeding period: autumn.
Puberty: about 2 years old.
Offspring: from fertilized eggs, larvae are formed - planula, covered with cilia.
Benefit / harm to humans: common jellyfish eats fish fry. In Asian countries (China, Philippines, Thailand, Malaysia, and Indonesia) it is eaten.
Population/conservation status: the population is large.
The structure of the eared jellyfish (Fig. 35). The body of the eared jellyfish is flattened and carries numerous short tentacles along the edge of the umbrella. The tentacle zone has eight shallow incisions, in which the marginal bodies - ropalia are located. These are organs of balance and light-sensitive. On the inner wall of the umbrella - subumbrella - in the center, on a short stalk, there is a cruciform mouth surrounded by four oral lobes. In a floating jellyfish, the oral lobes hang like hare ears, hence the name of the jellyfish. When capturing prey, the edges of the oral opening diverge and the mouth takes the form of a quadrangular, almost square opening. This allows predatory jellyfish to capture rather large prey.
Through the transparent walls of the body and the mesoglea (jelly-like, 97.5% water), the stomach located in the center is clearly visible, forming four pockets lined with endoderm.
In the depths of these pockets are gastric threads (rollers). These are accumulations of glandular cells that secrete digestive enzymes into the stomach cavity. A system of radial channels departs from the stomach. Four strongly branching canals coincide in direction with the oral lobes and are called canals
Type Cnidaria
Class Scyphozoa
Rice. 35. Scyphoid jellyfish Aurelia aurita: I- marginal bodies, or ropa-lii; 2- mouth; 3 - oral lobe; 4 - stomach; 5- radial channels; 6 - annular channel; 7 - gastric ridges; 8 - tentacles
I order. Branched canals of the second order, also among the four, are located correspondingly to the four pockets of the stomach. Interleaved with the branched channels are eight non-branched channels of the 3rd order. All radial canals are united by an annular canal running along the edge of the umbrella and form a complex gastrovascular system.
It has been experimentally proven that nutrients from the stomach centrifugally flow through eight unbranched channels. III order to the ring (fast distribution), and the process of their absorption and assimilation is ensured by a gradual movement to the stomach (centripetally) along eight branched channels I and II orders. Undigested residues are removed through the mouth opening.
When considering the marginal zone of the umbrella, one should pay attention to the fact that the ropalia are in depressions opposite the central branches of canals I and II orders. There are no tentacles here.
The gonads, or gonads, spatially coincide with the gastric filaments of the stomach pockets and are clearly visible from the side of the exumbrella. Unlike the gonads of hydromedusae, which are formed from ectodermal cells, the gonads of scyphoid jellyfish are formed in the endoderm.
It is useful to conduct a comparative review of the structure of hydro- and scyphomedusa (Table 4).
The structure of the ethers Aurelia aurita. In the development cycle of the eared jellyfish, there is an alternation of asexual and sexual generations - metagenesis, and the medusoid stage predominates in development. After the formation of reproductive products in dioecious jellyfish and internal fertilization, the eggs develop in special "brood chambers" on the grooves of the oral lobes. The resulting larva swims freely for some time, and settling on the substrate, successively forms scyphistoma, strobilui, after the separation of the horizontal buds from the strobila (strobilation process), the latter turn into a free-floating larva to the ether.
It differs from the adult ether jellyfish in the following structural features (Fig. 36). It is small in size, the edges of the umbrella are strongly indented and form eight (sometimes more) marginal lobes. In the depressions at the top of the marginal lobes, marginal bodies are located, from which ropalia later develop. Tentacles along the margin of the umbrella are absent in young ethers, but gradually develop in the areas between the marginal lobes. The cruciform mouth and stomach are present in the youngest ethers. The gastrovascular system is initially represented by direct channels I and II orders. As you grow and develop /1A 2
Aurelia eared (lat. Aurelia aurita) is a scyphoid jellyfish of the family Ulmaridae from the order Discomedusa (lat. Semaestomae).
This is the largest jellyfish found in the waters of the Black and Mediterranean Seas. Her transparent umbrella reaches a diameter of 40 cm. When meeting with her, it is recommended to be very careful, since even a light touch of her tentacles can cause severe burns.
Spreading
Aurelia eared lives in tropical and temperate waters of the seas and oceans of the planet, with the exception of the polar regions. The largest colonies of jellyfish are located in equatorial regions close to the coast.
Eared aurelias easily tolerate the pollution of their habitat and quickly adapt to environmental conditions, so they often settle in port waters or near power plant collectors that discharge warm water.
Morphology
The body of Aurelia eared is 98% water. Along the edge of the umbrella are receptor cells that perform the functions of balance organs and light-sensitive eyes. With their help, the jellyfish can determine prey and navigate in space.
Tentacles growing along the edge of the umbrella are designed to grab and move the victim to the oral cavities. An important role in the circulatory system of the jellyfish is played by water, which constantly circulates in the intestinal cavity. Aurelia eared absorbs oxygen dissolved in water, carrying out gas exchange processes with its entire body.
Aurelia poison is not dangerous for all creatures. For example, pilot fish fry very often hide between its tentacles. They are not afraid of poisonous stinging glands. Very often they can eat plenty of the remnants of their owner's food.
reproduction
In the course of their development, scyphoid jellyfish undergo alternation of generations. Polyps reproduce by budding, while jellyfish reproduce sexually.
Adult males release sex products into the water.
Then they penetrate into the brood chambers of females, where they subsequently fertilize and develop. After the end of this process, the eggs are in the oral cavities of the females until they turn into larvae. Then the larvae (planula) break away from the mother's body and sink to the bottom. There they turn into a single polyp called scyphilistoma.
The polyp leads a sedentary lifestyle. With the help of tentacles, he hunts for plankton. In winter, all adult jellyfish die, only polyps remain. With the advent of spring, it begins to bud and produces up to 30 young jellyfish. This process is called strobilization. One polyp gives life to both male and female individuals.
The larvae of tiny jellyfish go free swimming. Outwardly, they are very similar to adults, but only very small. The diameter of their umbrellas reaches 2 mm.
After a month, they increase to 1 cm and acquire a well-formed umbrella, from which tentacles begin to grow. After 3 months, they have sex glands, and they become ready for reproduction.
Behavior
Jellyfish drift in large colonies in coastal waters. They move in a reactive way. Having drawn water into the umbrella, and then, having contracted, they push it out.
At night, Aurelia eared descends to a depth of 10 meters, and during the day it rises closer to the surface. The main food consists of small fish, planktonic organisms and small jellyfish of other species.
Aurelia's weapons are stinging cells, which can infect the victim with poison. The mouth lobes pick up the immobilized prey and place it in the mouth opening, from where the food enters the intestinal cavity. The oral lobes of Aurelia are outgrowths from the mouth opening. Their inner surfaces are littered with stinging glands with deadly poison.
The intestine begins to secrete digestive enzymes and then proceeds to absorb the digested food. Undigested food remains through the mouth opening are brought to the surface.
Description
The diameter of Aurelia eared can reach 40 cm, and weight up to 10 kg. The body of a jellyfish looks like an umbrella with 8 cutouts along the edge. The flat umbrella is filled with a thick layer of gelatinous substance. A lot of tentacles grow along its edge.
The oral cavity is surrounded by 4 wide oral lobes. The receptor cells located along the edges serve as sensory organs.
The life expectancy of Aurelia eared is about one year.