Gulf of Koper towns of Koper, Izola and Piran (the northern shore), along with the villages of Ankaran, Bertoki, Jagodje, Dobrava, Strunjan and Fiesa, are located by the gulf. Gulf of Koper The Gulf of Koper or Koper Bay (, , ) is located in the northern part of the Adriatic Sea, and is a part of the Gulf of Trieste. The gulf, named after the city of Koper, is part of the Slovene Riviera and is entirely located in Slovenian territory. Crossed by the river Rižana, it is 18 km² large and spans from Debeli Rtič, next to the borders with the
Gulf of Bothnia a number of rivers from both sides; consequently, a salinity gradient exists from north to south. In the south the water is the normal brackish water of the Baltic Sea, but in the north, in the Bothnian Bay, the salinity is so low, from 0.4% near Kvarken to 0.2% in the northernmost part, that many freshwater fish such as the pike, whitefish and perch thrive in it. Being nearly fresh, the gulf is frozen over five months every year. The icing of the Baltic Sea begins and ends in the northern Gulf of Bothnia. Traffic restrictions for icebreaker assistance are