A jellyfish study got more than it bargained for this weekend when a vigilant bather reported the sighting of the potentially-lethal Portuguese man-o-war between Xlendi and Ta' Ċenċ.

The infamous, jellyfish-like, Portuguese man-of-war had been sighted in the Mediterranean but Saturday's recording is only the second such confirmed sighting in Maltese waters since 2001.

A Gozitan spotted the creature floating while out on his boat off the shore between Xlendi and Ta' Ċenċ and reported the presence of the "blue bottle", as it is also known, to the International Ocean Institute and the University of Malta, which have asked the public to report jellyfish sightings for research purposes.

The only evidence of a man-of-war found in Maltese waters so far had been in the form of a preserved specimen picked up in 2001 and kept by marine biologist Patrick Schembri.

Technically, the physalia physalis, as it is known scientifically, is not actually a jellyfish but a colony of different kinds of organisms (such as little polyps) that live in a cluster and together look like one big jellyfish.

The jelly-like creature gives a burning sting that is more painful than that of a jellyfish and can, in extreme cases, be lethal.

The University's study, headed by Alan Deidun and Aldo Drago, kicked off at the weekend. Reports can be made through e-mail at ioi-moc@um.edu.mt, SMS: 7922 2278 or through the dedicated website www.ioikids.net/jellyfish.