The Malta Independent 20 August 2019, Tuesday

Dreaded Portuguese man o’ war colonies spotted by kayakers in Comino Channel

Thursday, 18 April 2019, 15:23 Last update: about 5 months ago

The Spot the Jellyfish citizen science campaign received an alert from kayakers about two separate Portuguese man o’ war colonies (Physalia physalis) spotted within the north Comino Channel.

According to Prof. Alan Deidun, coordinator of the same campaign, the species, which is not a true jellyfish but rather a siphonophore colony of four different types of polyps known as ‘zooids’, is only rarely observed within Maltese coastal waters, with the campaign recording 10-15 times since August 2009.


Most of the previous sightings were consistently made along the shores of the islands and during the months of April and May, which fortunately don’t represent the main bathing season on our islands. Prof. Deidun asserted that the species is a resident within the Atlantic Ocean, being occasionally blown within the Mediterranean through the Straits of Gibraltar. Malta marks the easternmost outpost within the Mediterranean normally reached by the species, which probably reached our waters due to the persistently strong westerly winds pummelling the islands earlier this week, according to Prof. Deidun.

Prof. Deidun warns that the species inflicts very painful stings and the venom in detached tentacles and even in dead specimens (such as those which wash up on shore) can remain active for a few days and thus dead specimens should NOT BE TOUCHED. Applying vinegar or alcohol can actually intensify the pain sensation as it triggers the firing of further stinging cells. Best treatment would consist of the application of hot packs or hot water immersion, as specified within the MED-JELLYRISK sting treatment booklet currently available for free download on the Spot the Jellyfish website (

The colony has an air-filled bladder called the marissa or sail through which it manages to float. The species is commonly known as the Portuguese man-o-war by virtue of its resemblance to a 16th century vessel of Portuguese design, known as the caravel, which had triangular sails similar in outline to Physalia. Some polyps are specialised for capturing prey, others for feeding and others for reproduction, such that polyps are inter-dependent on each other. The species is native of tropical sub-tropical areas of the Atlantic and Pacific Ocean, occasionally being projected into the Mediterranean in spring by persistent westerly winds. Further information about the Portuguese man o’ war can be gleaned from: Portuguese man.pdf

The Spot the Jellyfish campaign enjoys the support of the Malta Tourism Authority (MTA) and of Nature Trust, Friends of the Earth, EkoSkola, the BlueFlag Malta programme and Sharklab. The initiative follows a citizen science approach and relies on the collaboration of the general public, mariners, divers, and especially the younger generations through their teachers and parents, by recruiting their assistance in recording the presence and location of different jellyfish through the use of a dedicated colourful reporting leaflet. The leaflet is reproduced within seaside panels affixed on all major local beaches with the support of the MTA. Reports of jellyfish sightings can be submitted to the Spot the Jellyfish campaign through email ([email protected]), campaign website (, campaign facebook page or through the tailor-made ‘Spot the Jellyfish’ smart phone app available for free download on different platforms.

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