The cnidarian phylum includes more than 10,000 species of aquatic animals which, depending on the type, live in s alt or fresh water. Among these animals are jellyfish, which are of different classes. One of them is the Scyphozoa, which is commonly called the true jellyfish and is exclusively marine. Among them, the pelagic jellyfish or purple jellyfish (Pelagia noctiluca), very common in certain maritime areas and about which we will tell you everything in this PlanetAnimal sheet.
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Origin
- Africa
- America
- Asia
- Europe
- Oceania
Characteristics of Pelagic Jellyfish
The main characteristics of the pelagic jellyfish are:
- Pelagic jellyfish exhibit radial symmetry.
- Her body is made up of specialized tissues: she has no organs.
- The nervous, digestive and respiratory systems are primitive, but they are still able to provide the basic functions necessary for the survival of the jellyfish.
- The tissues are divided into three: the outer epidermis, the inner dermis and a layer called the gelatinous mesoglea, which is similar to a kind of cartilage, but less compact.
- It has a single opening in the body: this corresponds to the oral space, for food and also for excretion.
- It has four lobes: these are called oral arms and are associated with the opening of the body mentioned above.
- The manubrium is divided into eight lobes: the shape can be bell or hemispherical.
- Coloration varies from purple, light brown, reddish brown to light yellow.
- The bell is bordered with a wavy shape: eight tentacles are located on the bell, quite elastic and fine in shape; they have a piercing function, by which she inoculates her toxins.
- The diameter of the bell is variable: it can range from 3 to 12 cm.
- Sensitive tissues are located in the lobes: they are light and smell receptors. So they are a type of chemoreceptor.
- They have differentiated gonads: i.e. female and male.
- The particularity of this jellyfish, hence its name, is its luminescence capacity: this is activated when the animal is disturbed or is in turbulent water.It can even secrete a gelatinous substance which is also luminescent. This is due to the presence of a protein.
Habitat of the pelagic jellyfish
The pelagic jellyfish has a wide global distribution and is present in the Atlantic, Pacific and Indian oceans. It is distributed mainly in large bodies of water, but also in coastal waters and it can even adapt to almost all areas of the marine environment, including temperate, warm or tropical waters. The pelagic or luminescent jellyfish lives mainly north of the Equator, in the North Sea, in the Canadian Atlantic, in the Gulf of Mexico, in the Mediterranean and in Australia.
Habits of Pelagic Jellyfish (Glow Jellyfish)
One of the habits of pelagic jellyfish is that they usually form large aggregations of individuals that can number thousands of jellyfish.To move, they perform rhythmic contractions with the underside of the bell, which helps them propel themselves. The gelatinous tissue of the mesoglea also provides buoyancy for these animals.
As is the case in the group of cnidarians, these jellyfish have a specialized organelle known as the nematocyst, capable of secreting a toxic substance that they inoculate their prey as well as all beings who bother them. In the case of humans, although it is not a species of deadly jellyfish, it causes skin conditions, which can be more or less painful. This usually happens in certain coastal areas, at a time when tourists frequent the beaches, as it is common for these animals to end up stranded in certain areas.
Feeding the pelagic jellyfish
This jellyfish, like the others, actively hunts its prey. To do this, it uses its tentacles, which contain cells called cnidocytes.Each of these cells is endowed with nematocysts, which function like a kind of sharp harpoon, which is introduced into the prey and which, once inside, inoculates the toxic substance.
These feeding and defense structures are so powerful that they can penetrate a crab's shell, which the jellyfish can then eat.
Digestion of this type of jellyfish takes place intra- and extracellularly, in specialized feeding tissues in an intestinal cavity. In this way, he can consume different types of animals, among which we can mention:
- Zooplankton
- Fish
- Crustaceans
- Eggs
- Other jellyfish
Reproduction of the pelagic jellyfish
The pelagic jellyfish has separate sexes. For reproduction, the male and the female release their gametes into the water, where fertilization takes place, which is therefore of the external type.Eggs and sperm are released through the animal's mouth from the gonads, which are located towards the central area of the body.
Once fertilization has taken place, a differentiated embryo is formed, called a planula, which has cilia that allow it to swim freely, moving in open water. Unlike other jellyfish, the pelagic jellyfish does not have a sessile polyp phase, since from the planula is born the form called ephyra (ephyre), which corresponds to a young jellyfish, which after a process of development and growth, transforms into an adult individual. This completes the reproductive cycle, in which the offspring receive no parental care.
If you want to know more about jellyfish reproduction and how jellyfish are born, we let you discover the following articles from PlanèteAnimal.
State of conservation of the pelagic jellyfish
There is no reported assessment of the conservation status of the pelagic jellyfish.However, it is very likely that, like other species of jellyfish, it is not endangered. On the contrary, the massive decline of natural predators and the modifications of the marine system due to climate change are rather increasing the population levels of the species. In the event that this happens, it would also not be appropriate, since there must always be a population balance for each group of animals.
Pelagic jellyfish pictures
