Box jellyfish bloom in yacht marinas

The Spot the Jellyfish campaign has received numerous reports over the past few days of sightings of the box jellyfish species - Carybdea marsupialis - all coming from the Ta Xbiex and Birgu marinas.

In all cases, the box jellyfish were reported as occurring in groups of less than five. Marine biologist Alan Deidun, coordinator of the campaign, said that the site-fidelity of the species - which seems to have a predilection for yacht marina environments - might stem from its preference for concrete walls (which it uses during some of the stages of its reproduction) or for nutrient-rich (polluted waters), or it might be that its larval stages are being transported by recreational vessels.

The box jellyfish has a roughly conical umbrella, with four long tentacles emerging from each corner of the umbrella and having roughly 4-5 times the length of the umbrella which is normally only 3cm long.

The species is highly transparent and quite difficult to spot in water, normally occurring at great depths, 500 to 1,000 meters. It is however occasionally nudged to the surface by currents.

Although not lethal as its Pacific Ocean counterpart - the sea wasp (Chironex fleckeri) which is listed as one of the most venomous animal species on earth - the Mediterranean box jellyfish species can still inflict painful stings.

The Spot the Jellyfish initiative website (www.ioikids.net/jellyfish) now gives users the possibility to search the total number of jellyfish sightings for each bay on an annual basis, from 2010 to 2012.

From such statistics, it transpires that a total of 384, 118 and 205 reports were submitted by the public to the initiative's database in 2010, 2011 and 2012 respectively.

The initiative is coordinated by Alan Deidun, Aldo Drago and staff of IOI-MOC, and enjoys the support of the Malta Tourism Authority (MTA), Nature Trust, Friends of the Earth Malta, 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 furthermore been projected on boards along major bays on both islands.

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 [email protected].

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 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.