The Curonian Lagoon is separated from the Baltic Sea by the Curonian Spit. The strait connecting the lagoon and the sea is located near the Lithuanian city of Klaipeda.
The bay is divided between Lithuania and Kaliningrad oblast of Russia, and it marks the border of Kaliningrad oblast. Most of the water area (1200 sq km out of 1600 sq km) belongs to Russia, and the rest, the northern part of the lagoon, belongs to Lithuania.
The lagoon is rather shallow, with an average depth of 3.7 meters. Nevertheless, there is a lot of fish in it, a total of 53 species: trout and whitefish, smelt and eel, carp and ide, sprat and cod, chub and nase. The water in the lagoon is almost fresh due to inflow from several rivers, including the Neman, Guild, and Deyma. The water level in the lagoon is 12-15 centimeters higher than in the Baltic Sea.
A lot of waterfowl are found in the Curonian Lagoon, including different kinds of geese and ducks, as well as the Eurasian coot. Hunting is a popular sport here: up to 40,000 birds are shot annually.
The Curonian Spit--the world's longest--is a long and narrow sandy peninsula. It is part of the national park of the same name.