A shallow northern Mediterranean arm holds 1,300 islands
The Adriatic Sea splits Italy from the Balkans as the Mediterranean’s northernmost arm, running from the Strait of Otranto to the Po Valley. More than 1,300 islands line mostly its eastern shore, counterclockwise currents circle three uneven basins, and surging acqua alta tides periodically flood the streets of Venice.
Maximum depth reaches 1,233 metres in the south; the north is a shallow shelf. Coastal cities such as Bari, Venice, Trieste, and Split help push shoreline population past 3.5 million. Etruscans, Illyrians, and Greeks settled early; Rome controlled the coasts by the second century BC, and medieval powers later contested the same narrow sea.
Fisheries, tourism, and shipping pay the bills: nineteen ports each move more than a million tonnes of cargo yearly. The name tracks the Etruscan town Adria, likely from Illyrian adur for water or sea; Romans said Mare Adriaticum or Mare Superum.
Its floor is lopsided. Average depth is about 260 metres, but the northern basin between Venice and Trieste seldom exceeds 100 metres and shallows to just 15 metres at its northwestern tip, forming the Mediterranean's largest continental shelf. Because it collects about a third of the fresh water reaching the Mediterranean, the Adriatic is less salty than its parent sea. Rivers including the Po, Neretva and Drin drain a basin of 235,000 square kilometres, and in the late nineteenth century Austria-Hungary pegged an elevation benchmark to mean sea level at a Trieste pier.
Croatia accounts for 1,246 of the islands, a tally that includes rocks exposed only at low tide; Cres and Krk tie as the largest at about 406 square kilometres each, and Brač rises highest at 780 metres. The smooth Italian shore lets the Western Adriatic Current run freely, whereas the jagged eastern coast produces far more tangled flows. When lunar alignment coincides with sirocco-driven surges, Venice floods in the acqua alta; the highest such tide, 194 centimetres, came on 4 November 1966. Trieste handles the most cargo, Split the most passengers.
Source: Adriatic Sea
