Background

The Moon Jellyfish is recognisable by the four crescent shaped ringlets, which can be pink or violet in colour. These structures are the animals’ gonads, which it uses to reproduce. The rest of the body, also known as the umbrella, is translucent. There are a number of closely related species of Moon Jellyfish and in the juvenile stages of these animals’ life cycle they are indistingushable. This means that scientists have to use genetic testing in order to classify individuals.

Habitat

They are one of the most widely distributed and common species of jellyfish. They are found throughout the world’s oceans, with the exception of extremely cold waters at the North and South Poles. Jellyfish move close to the surface of water in order to capture their prey. This makes these animals clearly visible from outside of the water.

Diet

Moon Jellies are carnivorous, feeding on small plankton. They use two methods of feeding; the first being a a sticky mucus to collect their prey on the surface of their skin. They then uses specialised hairs to move the food into their stomach. The second method is to use stinging cells which run down the tentacles, called nematocysts, to stun their prey. In order to survive they need to eat several times its own bodyweight daily.

Predators & Threats

Jellyfish are slow moving species and cannot move to safety quickly, making them an easy target for predators. Whilst they do have stinging cells, they are too short in to penetrate the thick skin of their predators. Sea turtles, sharks and in some cases other jellyfish are all known to feed on Moon Jellyfish.

Facts

  • Jellyfish have existed for around 650 million years, which pre-dates the dinosaurs.
  • The venoms of some species of jellyfish are so strong that they can kill a fully grown adult.
  • Jellyfish are made up of 95% water.

 

Common Name(s)Scientific Name
 Moon Jellyfish, Common Jellyfish, Saucer Jelly Aurelia aurita
Size
 Up to 40 cm in width
Lifespan
  ≤ 2 years

Best Time to Look

Adult Moon Jellyfish don’t tend to stay alive that long, however you can find juveniles throughout the course of the year.

Where to find Moon Jellyfish