Over the past week, swimmers have alerted the The Spot the Jellyfish team, based at the International Ocean Institute of the University of Malta, of an abnormally high density of ‘blue button’ jellyfish in the waters around Marsalforn.

Hundreds of the minute, but unmistakable (in view of their ethereal blue and perfectly spherical bodies), blue button (Porpita porpita) individuals were observed in a small area, clinging on to, and possibly feeding on, tentacles of the mauve stinger (Pelagia noctiluca).

The blue button is normally a rare occurrence in Maltese coastal waters and was first recorded from these waters in 2010 in Dwejra, Gozo, through the Spot the Jellyfish campaign, by a French girl holidaying in Malta.

The species is normally considered as a tropical one, being known from tropical parts of the Indian, Pacific and Atlantic Oceans, and hence its proliferation in the Mediterranean Sea might be another hallmark of the current warming trend being witnessed in the Mediterranean Sea.

The blue button is almost innocuous (since its tentacles might just cause some mild irritation to human skin) and strictly speaking is not a jellyfish as it belongs to the same group as Velella velella (By-the-wind sailor), with floating colonies consisting of several individuals.

The Spot the Jellyfish initiative is coordinated by Dr Alan Deidun, Prof. Aldo Drago and staff of IOI-MOC, and 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 campaign is an IOI-Kids Programme initiative, which 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 being widely distributed, and can be directly downloaded from www.ioikids.net/jellyfish, which is replete with snippets and anecdotes about different jellyfish species.

With the support of MTA, large posters have also been projected on boards along major bays on both islands. Over 1000 reports have been submitted by the public to the campaign since May 2010.

The reporting is done by simply matching the sighted jellyfish with a simple visual identification guide, giving the date and time of the sighting and indicating the number of jellies seen. Sightings can be also reported online or submitted through an SMS on 79 222 278, or by sending an email message to ioi-moc@um.edu.mt.

Strange jellyfish not included on the leaflet should be caught and kept in a bucketful of seawater prior to contacting IOI-MOC staff for retrieval to attempt a definite identification of the species. If this is not possible, photos of the same individuals should be taken.

The Spot the Jellyfish campaign launched in May 2010 has received international recognition for its citizen science value – for instance, global citizen science fora, such as the ‘Science for Citizens’ blog http://www.scienceforcitizens.net/blog/2010/08/spot-the-jellyfish-here-or-in-malta/ and the Science 2.0 network http://www.science20.com/citizen_science_journal/jellyfish_reporting_citizen_scientists_malta carried an extensive feature on the Maltese initiative.

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