Have you seen a jellyfish?
If so, tell us about it!
You can contribute to a long-term dataset by telling us about the animals you saw.

Report at jellywatch@ucy.ac.cy

welcome to ΜΕΔΟΥΣΑ website

a page for recording sightings of jellyfish in Cyprus sea areas.


Jellyfish have been present for more than ~ 540 million years, and appeared even before the dinosaurs. They can be found in all oceans and at all depths and vary in size.

The anatomy of the jellyfish is simple but functional and efficient. “Simple and perfect”. They are made up of 95% water and their “umbrella” has 2 membranes. The mouth is located underneath the umbrella, and leads to the “stomach”. A set of neurons is present on the outer membrane, and detects stimuli created by changes in the environment. Jellyfish breathe by diffusion and reproduce both sexually (release of sperm and eggs in the water) and asexually (budding).


anatomy of jellyfish


Jellyfish feed on plankton, small fish, fish larvae, crustaceans, or other jellyfish. Their predators are tuna, sharks, swordfish, sea turtles, and salmon.

The intensity of their toxicity varies from no reaction, to unbearable pain, and even death; due to the fact that they cause allergic reactions which in turn may cause a heart attack. The nematocysts, the poisonous tools, are found in the tentacles of the jellyfish. They are triggered involuntarily when they come into contact with a foreign body, even if the jellyfish is dead.

Not all jellyfish are stinging; many are harmless to humans, but it is always best to avoid touching them.

Problems caused by jellyfish ...

More for the different species here ...