Ladoga

this lakeThe Ladoga ringed seal (Russian: Ладожская нерпа; Pusa hispida ladogensis) is a freshwater subspecies of the ringed seal (Pusa hispida) 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.