p. 53 - 67 THE PERIODS OF MAXIMUM OSCILLATIONS OF THE BIVALVE CORBULLA MEDITERRANEA (COSTA) DENSITY Vasile Roventa et Marian Gomoiu Meteorological and Hydrobiological Institute - Bucharest Institut Roumain de Recherches Marines - Constantza Abstract On the basis of the mathematical method of self-correlation the multiannual periods of the maximum variations of the bivalve Corbula mediteranea density at Mamaia (Romanian Black Sea litoral) are established. These periods are: 3.1 years for Corbula populations at a depth of 4 m, 11.5 years for those at a depth of 8 and 6.9 years at a depth of 12 m.