"who had been shot into the Adriatic Sea"
Map of the Adriatic Sea - Credit: Norman Einstein
Satellite photo of Adriatic
The Adriatic is a large body of water that reaches north from the Mediterranean into the European continent between Italy on its west side and the Balkan Peninsula to the east (Greece, Albania, and the former Yugoslavia -- now the states of Slovenia, Croatia, Bosnia, Herzgovina, and Montenegro).
In other words, it is on the other side of the Italian "boot" from Pianosa.