Aurelia aurita, commonly known as Moon Jellyfish, includes about 25 species that like to stay in relatively warm waters. For practical purposes, they are all quite similar, if not identical; however, the genetic analysis points out clear differentiation.

Although the Moon Jellyfish can indeed be located all over the epipelagic area, its distribution is most typically observed close to shore and in upwelling sites, in which its food is more abundant. As a result of violent storms or surges that push them ashore, this animal isn’t a particularly great swimmer and is frequently discovered on coastlines.

Featured Image Credit: Nathan Rupert


Appearance

The bell of a Moon Jellyfish is pretty much clear or opaque, with one permeable circle in the middle that is typically a shade of blue. The Moon Jellyfish can be identified by its distinct quadruple clover-shaped gonads, which are visible through the top of the dome and typically range anywhere between 10 and 16 inches in diameter.

The Moon Jellyfish can be identified by its distinct quadruple clover-shaped gonads at the top of its dome
The Moon Jellyfish can be identified by its distinct quadruple clover-shaped gonads at the top of its dome

Credit: chezshai

The Moon Jellyfish tendrils are packed in particular irritating cells known as Cnidocytes, like other genuine jellies. The reason why they have the name “Moon” is because of their rounded, shining crown or bell and tiny appendages. Its overall anatomy makes the jellyfish more of a floater than a swimmer, which is notoriously difficult for them.

Diet

Moon Jellyfish feed on small life forms such as platyzoa, and planktons as well as larger forms like crustaceans and mollusks alongside fish eggs. The mechanism by which Moon Jellyfish acquire food is quite efficient, considering that their underwater mobility is practically non-existent, as they solely depend on favorable currents to push them in the favorable direction. The tentacles are laced with cnidocytes mixed in the mucosal lining, which work by exploding small particles on the prey’s surface, resulting in paralysis and rendering the prey immobile and helpless.

Habitat

Moon Jellyfish can be found in oceans where the temperature is anywhere between 43–88 °F; they typically are located in Greenland, the north-east Atlantic, the east coast of the US, and Canada, as well as in the Caspian. It’s not uncommon to find many Moon Jellyfish either washed up or in close proximity to the shoreline. 

Moon Jellyfish can be found near Greenland and the north-east Atlantic
Moon Jellyfish can be found near Greenland and the north-east Atlantic

Credit: Paul Gorbould

A large number of these jellyfish are called a “Bloom”, and it’s generally a sign that the surrounding area is negatively affected by human activity resulting in either reduction of predators or an upsurge in available prey supply. Either way, they are a fairly resilient species able to survive in water conditions most sea species would perish in.

Reproduction

The gonads are the distinguishing components at the apex of the bell.  Adult Moon Jellyfish reproduce by external fertilization, in which the male discharges sperm further into surrounding water and the female discharges eggs. After fertilization, the egg develops into a larva that spends considerable time in the pelagic habitat. The larva looks for a suitable location in the intertidal zone as it develops and ultimately adheres to the ocean floor, where it develops into a polyp, an upside-down jellyfish. 

Each organism forms multiple clones of itself while it goes through the polyp phase that asexually reproduces and swims away before developing into a fully developed Moon Jellyfish. Most astoundingly, Moon Jellyfish can reverse their life cycles so that they age backward, rendering them to practically live forever.

Threats

In addition to the leatherback sea turtle and the ocean sunfish, Moon Jellyfish are also reported to be consumed by a range of shorebirds that might be more attracted to the krill and other smaller arthropods.

Moon Jellyfish are near extinct in the wild
Moon Jellyfish are near extinct in the wild

Credit: msiew

These jellyfish are more vulnerable to fungal and other disease issues in the environment due to the heated water at the summer’s end,  where rapid daily mating and decreased natural food concentrations make tissue repair almost impossible. As a result, the majority of specimens are expected to perish.

Facts about the Moon Jellyfish

  1. Technically there are 25 species of Moon Jellyfish.
  2. Moon Jellyfish are able to reverse their aging process.
  3. Moon Jellyfish have the ability of bioluminescence.
  4. Moon Jellyfish have been around as early as 500 million years ago.
  5. Moon Jellyfish were passengers in the Space Shuttle Columbia mission in 1991.


FAQs

How poisonous are Moon Jellyfish?

The Moon Jellyfish is distinct from numerous other jellyfish because it lacks lengthy, highly effective stinging appendages. Instead, the bell border is lined with thousands of tiny, delicate tentacles. The Moon Jellyfish has a faint sensation, and also most individuals only experience minor irritation or none at all.

What happens if you get stung by a Moon Jellyfish?

If you are stung by a Moon Jellyfish, don’t be alarmed; it won’t hurt you much. Essentially, Moon Jellyfish don’t possess a sting with enough intensity to pierce flesh. Rather, they will only provide a slight tingling feeling. You might experience modest discomfort and irritability, but these feelings should pass quickly.

How long can Moon Jellyfish live out of water?

Moon Jellyfish are known to live in water with very little oxygen content in some polluted waters, and they are paradoxically as resilient as they are fragile. However, outside of water, they can live for less than an hour, and depending on how strong the sun exposure is, the time just gets less and less.

How long do Moon Jellyfish live?

A polyp Moon Jellyfish can live up to a quarter of a century before becoming a mature Moon Jelly, whereas an adult Moon Jellyfish only lives a year and a half in tank confinement. Even if they are completely safe from predators, the procreation renders their immune system too weak to counteract any bacteria resulting in death.

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