The Moon Jellyfish (Aurelia aurita) is also called the Saucer Jelly. It is a marine (saltwater) simple invertebrate (animal with no bones – is is soft-bodied). It has nerve receptors in its body.
The Moon Jellyfish is translucent (see-through) with an umbrella-shaped bell and long tentacles. It has four horseshoe-shaped gonads (reproductive organs) in the top of its bell.
The bell pulsates, which enables it to move through the water. It also conserves energy by drifting with the ocean currents and tides.
It measures 25-40 centimetres (10-16 inches) long.
The Moon Jellyfish is found in most of the world’s oceans, although it is predominantly found close to shore or inshore, in estuaries and harbours. It prefers warm waters with currents (not still waters).
It eats plankton, mullusks, crabs, fish eggs and other small organisms. It captures its food with its long venomous tentacles (arms). Each tentacle has stingers which release poison. The Moon Jellyfish brings the food into its body to digest. It has a lot of predators, such as birds, fish and turtles.
It is capable of only limited motion, and drifts with the current, even when swimming.
The Moon Jellyfish does not have gills or lungs to breath. It gets its oxygen from the water by diffusion through the membranes that cover its body (like skin).
Both males and females release eggs and sperm. So, each jellyfish can produce young without mating with the opposite sex. It is hermaphroditic. It begins its life cycle as planula larvae, then as sedentary polyps, and finally as medusa (the adult reproductive phase).
The Moon Jellyfish lives for about six months.
Photographer: Martina Nicolls
Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM