Pontobdella muricata infection of Raja clavata and Dasyatis pastinaca off the coast of Lesvos, Greece

An investigation of ectoparasites of skates caught off the coast of Lesvos Island, north-eastern Aegean, Greece was performed from May 2010 to February 2012. One parasite, identified as the marine leech Pontobdella muricata, was found on the skin of 0.43% of Raja clavata and 3.6% of Dasyatis pastinaca specimens examined during the investigation period. This is the first record of D. pastinaca as being a host to P. muricata. Macroscopic and microscopic observation of the lesions caused by the parasitism, revealed haemorrhages and swelling of the skin of R. clavata, a milder inflammation of the skin of D. pastinaca, congestion, necrosis and liquefaction of the skin at the site of leech attachment and a lesion with disappearance of upper skin layers after the detachment of the leech.