In the first part of the 19 century the dune from the lake to the sea was only 350 m long, but now it is about 2-4 km. Nowadays the water level has sunk more than 2 m. There is only 20-30 cm of clean water layer above slime. In summer the water becomes too hot for fish, but in winter fish often choke under ice. Many valuable fish species have disappeared, for example, eels, lake salmons and breams.
Some small rivers flow into the lake.
There are also 6 islands, their total area is 1.3 square km. In the shallowest places of the lake there are lots of slime and sapropel, in some places the layer of them is more than 2 m thick. There were a lot of eels some time ago. Now in the lake live perch, pike, roache, ide and crucian. Fauna is very rich in the surroundings of the lake.