State of the Arctic Marine Biodiversity Report: chapter 3.6: Marine mammals

Marine mammals chapter of the State of the Arctic Marine Biodiversity Report covering 11 Focal Ecosystem Components: walrus (Odobenus rosmarus), ringed seal (Pusa hispida) bearded seal (Erignathus barbatus), spotted seal (Phoca largha), ribbon seal (Phoca fasciata), harp seal (Phoca groenlandica) hooded seal (Cystophora cristata), beluga (Delphinapterus leucas), bowhead whale (Balaena mysticetus), narwhal (Monodon monoceros), and polar bear (Ursus maritimus).

Sea ice declines across the circumpolar Arctic are the most visible and dramatic impact of climate change. Changes to this defining aspect of the environment will have transformative impacts on ice-associated Arctic marine mammals through direct habitat loss; and indirectly through 1) changes in prey species abundance and distribution; 2) increased levels of ocean noise due to increased ship traffic and industrial activities; 3) increased risks of disease; and, 4) alteration of predator-prey relationships (Kovacs et al. 2011, Laidre et al. 2015). Initially, five marine mammal species (walrus (Odobenus rosmarus), ringed seal (Pusa hispida) , beluga (Delphinapterus leucas), bowhead whale (Balaena mysticetus) and polar bear (Ursus maritimus)) were identified as Focal Ecosystem Components (FECs) in the Circumpolar Biodiversity Monitoring Programs (CBMP) Arctic Marine Biodiversity Monitoring Plan (CBMP Marine Plan; Gill et al. 2011) as they are of substantial value to Arctic residents. In further evaluating Arctic marine mammals that require sea ice for part, or all, of their life histories, the CBMP Marine Mammal Expert Network included an additional six species for a total of 11 species considered useful for evaluating changes in Arctic biodiversity (Moore and Huntington 2008, Gill et al. 2011, Kovacs et al. 2011, Laidre et al. 2015). These species are highly visible components of the Arctic ecosystems and also an integral part of Arctic subsistence culture. The seven selected species are: beluga, narwhal (Monodon monoceros), bowhead whale, the ice sealsringed and bearded (Erignathus barbatus), walrus, and polar bear. Four of the selected species are sub-Arctic seals that breed on sea ice and spend part of the year deep into the Arctic: spotted seal (Phoca largha) and ribbon seal (Phoca fasciata) in the Bering Sea area (Burns 1981), and in the North Atlantic area. These species are associated with sea ice and will be affected by sea ice loss to various degrees depending on regional conditions, individual species ecological requirements, and individual species or stocks historic status. These 11 species, and the aspects related to them, are discussed in this chapter. Marine mammals that are present in the Arctic, but not endemic, are not considered here..