Franz Josef Land and snow bunting. Some ivory gulls, little auks and Brünnich's guillemots opt to spend the winter on the islands. The polar bear population of Franz Josef Land lies within the Barents Sea subpopulation, which also includes polar bears inhabiting Svalbard and the western coast of Novaya Zemlya. In 2004, the Barents Sea subpopulation was estimated at 2,650. There is also a population of Arctic fox, which typically have their territories near seabird habitats. Being declared as a marine mammal sanctuary, the island has rich biodiversity of rare marine mammals. Three species of seals habit the archipelago. Harp seal is the
Franz Josef Land with streams only forming on the largest islands. The longest river is long and forms on George Land, while there are several streams on Alexandra Land, the longest being . There are about one thousand lakes in the archipelago, the majority of which are located on Alexandra Land and George Land. Most lakes are located in depressions caused by glacial erosion, in addition to a smaller number of lagoon lakes. Their sizes vary from to . Most are only deep, with the deepest measured at . The sea currents surrounding the archipelago touch eastern Svalbard and northern Novaya Zemlya. The