Moon Jellyfish Aurelia spp.

The Moon Jellyfish is native to coastal and deep ocean (pelagic) waters worldwide with different species in different regions. The different species look similar and are of similar size and habits.

It is translucent, generally whitish and can look attractive absorbing coloured light. It has four incomplete circles, sometimes purplish, in its bell - these are its reproductive gonads. The bell can grow to 40cm across but usually reaches only half that. The adult medusa has 4 short, frilly feeder tentacles with, at worst, a very mild, fleeting sting.

The Common or Atlantic Moon Jellyfish, Aurelia aurita, is native to cold and temperate waters of the northern Atlantic Ocean from Greenland and Scandinavia to the Iberian Peninsula across to Canada and northern USA.

The Pacific Moon Jellyfish, Aurelia labiata, is native to the northern Pacific Ocean from eastern Asia to western North America.

It has the usual 6-stage jellyfish life cycle of egg, larva, polyp, budding polyp which can reproduce asexually, ephyra and medusa (adult) with sexual reproduction. Above images include ephyrae and juvenile medusae.

Like all jellyfish, they have no brain, eyes, blood, heart or respiratory system and are 95% water. Diet is zooplankton and shrimp. They can gather in large aggregations and, since they drift in the current rather than swim, mass strandings on beaches can occur.