p. 143 - 150 MALADIES SIGNALEES CHEZ MYTILUS GALLOPROVINCIALIS LMK. DE LA BAIE DE MAMAIA - LITTORAL ROUMAIN DE LA MER NOIRE Elena Dumitrescu et Tania Zaharia Institut Roumain de Recherches Marines Constanta Abstract The pathological researches carried out in 1991 aim at the identification of the diseases of Mytilus galloprovincialis LMK. at the Romanian littoral, Mamaia bay. The mussel is a water filtering marine organism, with an active part in proving the waters it lives in and interesting for culture; it has been affected by an infection caused by germs belonging to genera Vibrio and Aeromonas and 15 parasitoses caused by parasite protozoa, worms and crustaceans. The diseases were more frequent in summer time when a poor quality of the marine environment has also been noted. The infections with Vibrio and Aeromonas have caused low mortalities with the mussel population in Mamaia bay, while the parasite infestations haven't caused visible pathological modifications. Among the parasites one can mention the protozoan Haplosporidium spp. affecting the gills and liver-pancreas of mussel.