UNDERWATER ARCHAEOLOGICAL SURVEY IN THE SOUTHERN HARBOR OF MESAMBRIA (Nayden Prahov – naydenprahov@yahoo.com, Kalin Dimitrov) The area for the dredging works, which was explored, was c. 400 m long and c. 100 m wide. The harbor was from 6 m to 9 m deep. Diving surveys were carried out and geophysical explorations were performed with a multi-beam echo sounder and side-scan sonar, on the basis of which a detailed bathymetric 3D model was created. During dredging works in the past, a number of archaeological finds were discovered in the harbor.