Adriatic Sea (ancient Adria or Mare Adriaticum), arm of the Mediterranean Sea, southern Europe, between the eastern coast of Italy and the western coast of the Balkan Peninsula. At the southern extremity is the Strait of Otranto, which connects it with the Ionian Sea. The Gulf of Venice, in the north, and the Gulf of Trieste, in the northeast, are the principal Adriatic embayments. The western coast is comparatively low and has few inlets, and the north is marshy and edged with lagoons. On the east the Albanian coast is steep and rocky, and the coasts of Bosnia and Herzegovina and Croatia are fringed with islands. The area of the sea is 132,000 sq km (51,000 sq mi). The rocky eastern coasts are dangerous for mariners in the winter because of the prevailing northeastern gales (bora). Trieste, Venice, Ancona, Bari, and Brindisi, Italy, are the chief ports. The fisheries of the Adriatic are highly productive.