In the waters of the Black, Azov and Baltic Seas many mysterious creatures dwell, one of which is the Aurelia jellyfish, called the Long-eared because of the four blades, located under the gel-like dome and strikingly reminiscent of hare ears. There is nothing surprising in the fact that today this weightless marine resident is of interest to many aquarists.
View scyphoid from detachment discomeduz.
The natural habitat of eared aurelia is the coastal waters of the temperate and tropical seas. The most numerous colonies of jellyfish can be found in the equatorial bands close to the coast, where they often form dense accumulations of fairly large extent.
Aurelia has a pelagic lifestyle. In simple terms, they populate areas that are not in close proximity to the bottom.
This marine inhabitant is a type of invertebrate eurybiont., therefore, it is able to tolerate significant fluctuations in ambient temperatures and constant changes in the level of salt in water, which explains its extremely wide distribution.
Without exception, the scyphoid jellyfish swim poorly. They only rise from the depths and sink again, motionlessly freezing for some time in the water column.
After storms, the entire coastal area is literally strewn with aurelia.
Until recently, this type of jellyfish was considered harmless to humans. However, in the Gulf of Mexico there have been cases of people getting severe burns when they come into contact with eared aurelia. In the Black Sea for a bathing person such jellyfish is not a serious threat.
Is that her stinging cells can cause minor irritation, comparable to what remains after contact with nettles.
Externally, eared aurelia resembles a transparent umbrella. The jellyfish have no rigid skeleton. The basis of the body, which is 98% fluid, is represented by a gel-like dome covered with epidermal cells.
The size of a marine inhabitant sometimes reaches 50 cm.
Along the edges of the body there is a huge number of thin tentacles hanging down, dotted with stinging cages – the main weapon of the jellyfish, with which it paralyzes small animals. Continuous contraction of the muscle fibers of the dome provides its movement and creates a stream of water that sends plankton into the oral cavity.
Fully formed larvae of the planula leave the brood chambers of the jellyfish and swim for several days in the water column.
Along the edges of the umbrella are complex senses – ropalia. With their help, the eared aurelia is oriented in space and keeps at some distance from the sea smooth surface so that the surging waves do not damage her body.
In the central part of the lower side of the dome is a mouth surrounded by two pairs of blades. By their size it is easy to determine the sex of the jellyfish.
In the female, the lobes are much larger – they contain chambers for ripening of larvae. Through the mouth and throat, food enters the stomach, and then due to the work of the flagellated epithelium enters the radial channels.
Undigested residues go the same way in the opposite direction and are brought out.
The eared jellyfish is a dioecious intestinal-cavity animal, which gives birth to offspring only once in its entire life, after which it dies. An interesting fact is that aurelia show a peculiar concern for their brood, which cannot be said about the other representatives of the scyphoid jellyfish. The life cycle of the sea animal consists of several stages:
- Bilayer embryo developing in an egg.
- Larva (planula).
- Mature individual.
Having attached to the substrate, the larva is transformed into a single polyp that actively feeds, grows in size and can even multiply.
In females hovering in the water, the oral lobes are lowered; therefore, the eggs that leave the mouth opening penetrate special troughs, move along them and fall into the pockets, where their fertilization and further development takes place. Gradually, the embryo becomes covered with cilia that help it swim, and eventually turns into a larva.
For a while it keeps in the water column, and then sinks to the bottom and is fixed on it with the help of the front end. A mouth with tentacles emerges from the upper part of the body, and the larva turns into a polyp, visually resembling a hydra.
At the next stage, its division occurs, which is provided by transverse constrictions that cut into the body. So there are young Aurelia.
Breeding aurelium at home has its own nuances. For jellyfish, a special reservoir is needed, providing a smooth circular flow in which they will not be afraid of collisions with objects in their path.
This is an extremely important point, since the delicate and soft body of the eared aurelia can easily be damaged by even a minor blow. Finally, you need to keep in mind that the aquarium should be spacious enough, otherwise the jellyfish will not be able to fully straighten their body.
The specificity of the content of aurelia in an aquarium is also in the fact that there should be no aeration in the tank, since air bubbles, penetrating under the jelly-like dome, can violate its integrity, and this is fraught with the death of a living creature. No additional lighting is also required, one decorative lighting will be quite enough.
Thanks to carousel aquariums, the maintenance of jellyfish at home has become possible and convenient.
Jellyfish can be kept in conditions of minimal water filtration. To maintain its quality at the proper level, you just need to regularly change the contents of the aquarium.
Jellyfish do not survive in water, which contains a lot of organic substances and nitrogenous compounds. Aurelia is not liked when other stinging animals (for example, hydras) are shared with them.
In terms of food, these creatures are completely unpretentious. They are well suited:
- finely chopped seafood.
However, in specialized stores there is always a ready-made feed, designed specifically for such inhabitants of the aquarium. As practice shows, the Aurelia eared jellyfish feels rather well in captivity.
Some aquarists not only successfully contain them, but also breed, observing all stages of development.
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