Parasitic infections of Chamelea gallina (Mollusca, Bivalvia) from commercially exploited banks of the Adriatic Sea

A parasitological survey of the bivalve Chamelea gallina was carried out fr om natural beds of the Adriatic Sea, where anomalous mortalities were obser ved during the last years (1997-1999). The occurrence of protozoans belongi ng to the families Porosporidae, Hemispeiridae and Trichodinidae was record ed. Porosporidae of the genus Nematopsis, present with 4 species, showed a prevalence of 100%, irrespective of sampling localities, season or bivalve size, but differences were found when percentage of infection was calculate d per organ. As for the genus Porospora this is the first record in C. gall ina. Among Hemispeiridae, the genera Ancistrum and Boveria were found in th e gills. The results suggest that severe infections of protozoans of the ge nus Nematopsis could cause a not negligible respiratory sufferance, with a possible role in the decline of the natural banks.