East Prussia's coast is characterised by two headlands, so-called spits. They separate two shallow water areas from the open sea which are called lagoons. The spits were only formed after the last ice age about 10,000 years ago. The Vistula Spit is 70 km long and 1.8 km at its widest point. The Curonian Spit is 98 km long and 3.8 km at its widest point. The Curonian Lagoon is about seven times as large as Lake Constance.
The spit was formed by the continuous deposition of sand by the sea current from west to east in front of a former bay. A growing sandbank dammed up several rivers and formed a barrier to the open sea. Thus, a shallow water zone was created, the lagoon, which is connected to the Baltic Sea at one point only. Fresh and sea water mix here to give brackish water and create ideal conditions for fish to breed in.
Particularly impressive on the spit were huge dunes, which today are increasingly overgrown, as well as bird migration in autumn.
Illustration:
Curonian Spit near Rossitten (today Rybachy) on the Baltic Sea coast, 2014. Photo: Dr Christoph Hinkelmann