Thursday, May 14, 2015

Freshwater Jellyfish in Greece

Fall 2014 Marathon Lake, Attika. 

Back on Sept 30th 2014 during a field research expedition, my colleagues and I were lucky enough to stumble upon a really interesting sight at an irrigation canal here in Attika: A freshwater jellyfish!

We immediately collected samples, did some research on this and published this in an obscure but charming scientific periodical (Journal of Limnology) since it is the first time we see it in this area and we got some interesting results in the DNA analyses showing that there are different varieties of these alien medusas in Europe... (please read our paper).

The species I have photographed here is in the genus Craspedacusta (first described by Lankester 1880). Craspedacusta in scientific naming roughly means "border guard", referring to the slightly stinging tentacles along the border of the body - the names was a synthesis from the Greek "kraspedo", meaning border and the Latin "custos", meaning guard.

Please, if anyone has any information of sightings from Greece I would be very appreciative in receiving any reports (with photos please).

The Internet is full of data on this interesting alien species, for example:

For a download of our paper on this issue:

Lake Marathon and the exact location where Craspedacusta sowerbii was found (map created by Ioannis Karaouzas)

P.S. #1. Our friends at the Greek Wetland Biotope Center (EKBY) in Thessaloniki also reported their find of Craspedacusta in Lake Marathon (also observed in late August of 2014 and directly inside the lake waters...); and they also found a huge bloom of Craspedacusta at one of the artificial reservoirs in the Nestos River, also in 2014! So the aliens may be widespread in Greece - we need to track it!

P.S. #2. I was informed by our former institute director that medusas were found in the the reservoirs and lakes of Central western Greece (Acheloos basin) in the past (however I don't know if it was this or another species). So....I'm very glad I posted this item. Reason for a new review of the subject matter, and a correction to our alleged "discovery", in a short communication.

Please send pictures if you have any more evidence!


  1. Σταμάτη γεια σου. Την Craspedacusta την εχουμε εντοπίσει και στα Κρεμαστά (1980-1985), στην Τριχωνίδα, στην Αμβρακια, και στο Καστρακι. Ανατρέξει σε παλιές τεχνικές εκθέσεις που μαλλον υπάρχουν στη βιβλιοθήκη.
    Συνέχισε την όμορφη δουλειά σου!

  2. Ευχαριστώ πάρα πολύ Θόδωρε, νιώθω άσχημα για την παράληψη. Και ειδικά μια τόσο παλιά αναφορά ('80-85) στα Κρεμαστά- θα είχε σημασία σε διεθνές επίπεδο - τότε υπήρξαν ελάχιστε αναφορές από τις Μεσογειακές χώρες (...θυμάμαι μια πρώτη δημοσίευση μιας φίλης μου της T. Ferreira, από Πορτογαλία από τα μέσα '80). Γενικά αυτά πρέπει να δημοσιεύονται!!! Ή να υπάρχει κάποιο αποθετήριο καταγραφών βιοποικιλότητας. Δεν ξέρουμε τι έχουμε.... (Ως προς την "διόρθωση" σε παρακαλώ αν βρεις την επιβεβαιωμένη αναφορά από Κρεμαστά, Τριχωνίδα, Αμβρακία, Καστράκι - είναι σημαντικό να κάνουμε ένα short communication.