Wildlife

By: Reid Brewer

The Bering Sea and Aleutian Islands are home to 450 species of fish and invertebrates, 50 species of sea birds and at least 25 species of marine mammals. The biological productivity of this area is driven by the seasonal differences in exposure to sunlight and availability of nutrients. The long summers days allow phytoplankton to grow, while winter storms raise nutrients from the sea floor. This combination of sunlight and nutrients allows for a prolific food web which results in a diverse and abundant ecosystem.

Fish and invertebrate species in Unalaska are often seen as the result of sport and subsistence fisheries. Commonly captured fish species include Pacific halibut, Pacific cod, many species of salmon and rockfish, sculpin, greenling, various species of flatfish and others. Many species of invertebrates can be seen on intertidal beach walks and others are captured in various fishing gears. Local invertebrate species include Red King crab, Tanner crab, Razor clams, Butter clams, Gumboot chitons, Shield limpets, Blue mussels, and north Pacific giant octopus. Intertidal invertebrates include a vast array of seastars, urchins, anemones, snails and seaweeds.

Each summer in the Bering Sea, 40 million to 50 million seabirds feed and make nests. The abundance of seabirds is often driven by the availability of food sources, migration routes, and changes in the rates of mortality. Near Unalaska, the predominant species include Bald eagles, ravens, cormorants, guillemots, and various species of gulls. Other species sometimes seen include horned and tufted puffins, murres, shearwaters, fulmars, auklets, kittiwakes and species of albatross. Oystercatchers are prevalent throughout Unalaska as are several species of sea ducks like the Spectacled and Steller's eiders.

Unalaska also plays host to a suite of marine mammals all capitalizing on the prolific food web. Humpback whales feed in Unalaska Bay in July and August before they migrate to their winter calving ground in Hawaii. Endangered Steller sea lions and threatened Northern sea otters are regular sights near Unalaska preying upon local fish and invertebrate species. Rare but occasional sightings include Harbor porpoises, Pacific white-sided dolphins, Dall's porpoises, and Harbor seals. Occasionally Killer whales will visit the outer bay looking for fish or mammal prey.

Though most of species described above are seasonal visitors in the summer time, others are year-round residents that seem perfectly happy with winter weather. One thing is for certain, Unalaska and the Aleutian Islands offer a door-step view of some of the most spectacular wildlife in the world.

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See related photo gallery: Plants and Wildlife