A two rare species of jellyfish have been reported in Maltese waters.

The Spot the Jellyfish team, based at the Malta Operational Centre of the International Ocean Institute, said that the first is the moon or saucer jellyfish – Aurelia aurita – is distinguished by its quartet of horseshoe-shaped gonads (reproductive organs) found just beneath the surface of its bell.

This species is translucent and non-stinging and is normally much more abundant in the Atlantic and in the western parts of the Mediterranean, since it prefers temperate conditions. It is consumed by a number of predators, which include the leatherback sea turtle and many seabirds. The species rarely survives for more than six months.

Also reported near Malta is the minute but beautiful Cladonema radiatum species, characterized by its bright orange and highly visible eyespots at the base of their tentacles.

The polyp stage of this jellyfish is normally found attached to seaweeds or to seagrasses, like Posidonia oceanica. The species is a cosmopolitan one, being known from the Mediterranean, North Sea, Atlantic and even as far afield as Japan. It has a hopping way of swimming, then it suddenly folds its tentacles and lets itself descend.

"Its recent presence in Maltese waters is somewhat anomalous as the species is normally encountered during the warm June-September period when it causes a tingling sensation to bathers," the team said.

The Spot the Jellyfish initiative is coordinated by Prof. Aldo Drago with the technical and scientific assistance of Dr Alan Deidun and staff of IOI-MOC (International Ocean Institute – Malta Operational Centre). It enjoys the support of the Malta Tourism Authority (MTA) and of Nature Trust, Friends of the Earth, EkoSkola and the BlueFlag Malta programme.

Further infromation can be found on www.ioikids.net/jellyfish