Ladoga seal Ladoga seal The Ladoga ringed seal (; Pusa hispida ladogensis), is a freshwater subspecies of the ringed seal ("Pusa hispida") which are found entirely in Lake Ladoga in northwestern Russia. The subspecies evolved during the last ice age, about 11,000 years ago. As the glaciers retreated and water levels changed, the Baltic ringed seal (including Ladoga seals) was trapped in freshwater lakes and separated from the Arctic ringed seal. It is related to the even smaller population of Saimaa ringed seals in Lake Saimaa, a lake that flows into Ladoga through the Vuoksi River. The adult Ladoga seal grows to
Lake Ladoga Finland, between 4,000 and 2,000 BP. Dating of some sediments in the northwestern part of Lake Ladoga suggests it happened at 3,100 radiocarbon years BP (3,410–3,250 calendar years BP). The Ladoga is rich with fish. 48 forms (species and infra specific 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. Commercial fishing was once a major industry but has been hurt by overfishing.