The Adriatic Sea () is a body of water separating the Italian Peninsula from the Balkan Peninsula. The Adriatic is the northernmost arm of the Mediterranean Sea, extending from the Strait of Otranto (where it connects to the Ionian Sea) to the northwest and the Po Valley. The countries with coasts on the Adriatic are Albania, Bosnia and Herzegovina, Croatia, Italy, Montenegro, and Slovenia.
The Adriatic contains more than 1,300 islands, mostly located along its eastern coast. It is divided into three basins, the northern being the shallowest and the southern being the deepest, with a maximum depth of 1,233 metres (4,045 ft). The prevailing currents flow counterclockwise from the Strait of Otranto. Tidal movements in the Adriatic are slight, although larger amplitudes occur occasionally. The Adriatic's salinity is lower than the Mediterranean's because it collects a third of the fresh water flowing into the Mediterranean, acting as a dilution basin. The surface water temperatures generally range from 30 °C (86 °F) in summer to 12 °C (54 °F) in winter, significantly moderating the Adriatic Basin's climate. The Adriatic Sea sits on the Apulian or Adriatic Microplate. In the Late Oligocene, the Italian Peninsula first formed, separating the Adriatic Basin from the rest of the Mediterranean. The western coast is alluvial or terraced, while the eastern coast is highly indented with pronounced karstification. There are dozens of marine protected areas in the Adriatic, designed to protect the sea's habitats and biodiversity—more than 7,000 species are identified as native to the Adriatic, many of them endemic, rare and threatened ones.
