The Barents Sea is inhabited by 21 species of marine mammals and is an important feeding ground for a range of large whales.
Whales include fin whale Balaenoptera physalus, minke whale Balaenoptera acutorostrata, humpback whale Megaptera novaeangliae, and sperm whale Physeter macrocephalus. Among the smaller whales and dolphins, the Barents Sea is important for northern bottlenose whale Hyperoodon ampullatus, killer whale Orcinus orca, white-beaked dolphin Lagenorhychus albirostris, narwhal Monodon monoceros, and beluga whale Delphinapterus leucas.
Among other marine mammals, grey seal Halichoerus grypus, harp seal Pagophilus groenlandicus, walrus Odobenus rosmarus, and polar bear Ursus maritimus are present in globally important numbers.
There is limited information on the trends in cetaceans, though humpbacks at least are believed to be recovering from past overexploitation. Numbers of both grey seals and walruses were reduced by past hunting; recent evidence shows that grey seal is recovering. Numbers of polar bears increased in the last quarter of the 20th century, but trends since 2000 are unclear.
Threatened and declining marine mammals according to OSPAR:Balaena mysticetus Bowhead whaleBalaenoptera musculus Blue whaleEubalaena glacialis Northern right whalePhocoena phocoena Harbour porpoise