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Dreaded jellyfish moves further west

01 February 2017

Evidence has recently emerged that the nomadic jellyfish (Rhopilema nomadica), one of the most invasive and impacting marine species in the Mediterranean, is moving further west in the Mediterranean, after being recorded off the western coast of Sicily, at the island of Levanzo (Aegadian Islands), and off the south-western coast of Sardinia. Ever since it’s introduction in the Mediterranean Sea in the late 1970s, this Indo-Pacific species has moved progressively west, closing off beaches (by virtue of this painful sting) and coastal power plants in Israel (by clogging cooling water intake pipes) and hampering fishing activities through its sheer numbers. The species normally blooms during the summer period.

The species was previously recorded in Maltese waters, in 2011 by the late Shaun Arrigo, but luckily the species so far has not formed large aggregations, as in other neighbouring countries as Tunisia. The best treatment for its sting, as highlighted within the MED-JELLYRISK project ( is through the application of ice packs wrapped in cloth.

This finding has been reported in a scientific paper currently in press within the Bioinvasions Records journal, which can be accessed from the following link:

and has emerged through the Spot the Jellyfish campaign which is running for the eight consecutive year. The public is invited to submit their jellyfish photos and reports to this citizen science campaign through the Spot the Jellyfish website (, through the campaign facebook page or over email ( The campaign is coordinated by Prof. Alan Deidun from the Department of Geosciences at the University of Malta and is supported financially by the International Ocean Institute (IOI) and by the Malta Tourism Authority (MTA).