Lake Ladoga is a freshwater lake located in the Republic of Karelia and Leningrad Oblast in northwestern Russia, not far from Saint Petersburg. It is the largest lake in Europe, and the 14th largest lake by area in the world. The lake's area is 17,891 km² (excluding the islands). Its length (north to south) is 219 km, average width is 83 km, average depth is 51 m, maximum depth is about 230 m (in the north-western part). There are about 660 islands, with a total area of 435 km². Ladoga's level above the sea is 5 m on average. Most of the islands, including the famous Valaam archipelago, Kilpola and Konevets, are situated in the north-western part.
The Ladoga is rich with fish. 48 forms (species and infraspecific taxa) of fish have been encountered in the lake, including roach, carp bream, zander, European perch, ruffe, endemic variety of smelt, two varieties of Coregonus albula (vendace), eight varieties of Coregonus lavaretus, a number of other Salmonidae as well as, albeit rarely, endangered European sea sturgeon. Nizhnesvirsky Natural Reserve is situated along the shore of Lake Ladoga immediately to the north of the mouth of the River Svir.