Seabirds at high latitudes may respond to climate change in a variety of ways, including range contractions or expansions and/or seasonal or annual shifts in distribution. Since 2006, three species of seabirds have been reported in the eastern Chukchi Sea for the first time: the Short-tailed Albatross (Phoebastria albatrus), Northern Gannet (Morus bassanus), and Rhinoceros Auklet (Cerorhinca monocerata). Sometime prior to 2006, the Ancient Murrelet (Synthliboramphus antiquus) expanded its usual maritime range north into the eastern Chukchi and now has reached the Beaufort Sea. The gannet appears to have entered the Pacific via the Northwest Passage, whereas the other three species have moved north from the Pacific. Whales, other seabirds, and diatoms have been recorded moving between the Atlantic and Pacific via the Northwest Passage in the past 15 years as sea ice has retreated and the passage has opened. Because of broad-scale changes to the Chukchi ecosystem and because of increased sampling of the region, we anticipate that additional seabirds will be recorded in the Chukchi and Beaufort seas from the North Pacific and possibly the North Atlantic.
The Pacific arctic marine region is undergoing rapid physical and biological change as a result of climate change (Grebmeier et al. 2006a, b, Overland and Wang 2011, Sigler et al. 2011, Grebmeier 2012). Climate-change models suggest that the increases in air and water temperatures are greatest at high latitudes (IPCC 2007), influencing biological change at multiple trophic levels. For example, the part of the northern Bering Sea south of St. Lawrence Island has changed from an arctic to a subarctic environment in recent years: the cover of sea ice has decreased, blooms of phytoplankton within the ice are diminished, and the abundance and biomass of communities of benthic organisms have been reduced, leading to reduced use by benthic-feeding marine mammals and an increase in populations of pelagic fishes in that region (Grebmeier et al. 2006b). Because of warming and the northward advection of water from the Bering Sea, boreal and subarctic benthic invertebrates also have expanded their distributions northward into the Chukchi Sea, as have the gray whales (Eschrichtius robustus) that feed on them (Grebmeier 2012). Climate change also is expected to alter distributions of species such as ice-pupping seals and marine fishes in the Pacific Arctic (Sigler et al. 2011), and there is evidence that, in the Okhotsk Sea (eastern Russia), the productivity of both planktivorous and piscivorous seabirds is changing with climate-associated changes in the marine ecosystem (Kitaysky and Golubova 2000).
Seabirds, which are highly mobile, may be expected to be prominent bellwethers of change in arctic marine ecosystems. One facet of changes in these ecosystems is range contractions or expansions and/or seasonal or annual shifts in seabirds’ distributions. In this paper, we detail recent records of species new to the marine avifauna of the Chukchi and Beaufort seas, species that may be responding to climate change. Here, we report and interpret these observations with respect to changing environmental conditions in arctic Alaska.