p. 263 - 289 DYNAMICS OF THE SETTLEMENT OF THE BIVALVE MYA ARENARIA L. ON THE ROMANIAN SHORE OF THE BLACK SEA M.T. Gomoiu and A. Petran Romanian Marine Research Institute Constantza Abstract A number of 327 samples collected in 1972 between Constanta and Sulina from depths between the sea shore and 30 meters provided data for establishing the qualitative and quantitative distribution of the bivalve Mya arenaria on the Romanian shore of the Black Sea. Comparison of 1972 data with those obtained in previous years showed that the settling of Mya at the Romanian coast was not a completed process. Penetration of the Corbula biocenosis by Mya involved no essential qualitative or quantitative alterations in the aboriginal malaco- fauna, the settling of this further bivalve bringing about an increase in the biological output of the sites it occupied.