New uncommon jellyfish species have been seen in Maltese waters for the first time, according to the Spot the Jellyfish team at International Ocean Institute’s Malta Operational Centre (IOI-MOC) based at the University.
One species is the moon or saucer jellyfish – Aurelia aurita – which is distinguished by its quartet of horseshoe-shaped gonads (reproductive organs) found just beneath the surface of its bell.
The species is translucent and does not sting, and is normally much more abundant in the Atlantic and in the western parts of the Mediterranean since it prefers temperate conditions.
It is eaten by a number of predators, which include the leatherback sea turtle and seabirds. The species rarely survives for more than six months.
The second new jellyfish species is the minute but beautiful Cladonema radiatum, characterised by its bright orange and highly visible eyespots at the base of its tentacles. It has a hopping way of swimming, but then it suddenly folds its tentacles and let itself fall.
The species is found in the Mediterranean, North Sea, Atlantic and even as far afield as Japan. During its polyp stage this jellyfish is normally found attached to seaweeds or seagrasses.
Its recent discovery in Maltese waters is somewhat strange as the species is normally encountered during the warm June to September period when it causes a tingling sensation to bathers.
The two jellyfish species were reported to the IOI-MOC by Greg Nowell from Sharklab (Malta) and Raymond Caruana from the San Luċjan Aquaculture Research Centre.
The Spot the Jellyfish initiative is coordinated by Aldo Drago with the technical and scientific implementation of Alan Deidun and staff of IOI-MOC. It relies on the collaboration of the public, sailors, divers, and especially children, through their teachers and parents.
A leaflet aimed at facilitating the process of identifying and reporting jellyfish may be downloaded from www.ioikids.net/jellyfish.
Sightings of jellyfish may be submitted by e-mail ioi-moc@um.edu.mt, by sending a text/image message to 7922 2278, or via website.