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Walrus Islands — State Game Sanctuary
Fish and Wildlife

The following provides a brief summary of the diverse fish and wildlife resources within the WISGS. Additional information (ADF&G Species write-ups and Wildlife Notebook Series write-ups) on specific species can be accessed through the hyperlinked text. The Round Island Mammal Checklist and Round Island Bird Checklist are available through these links.

Marine Mammals

The waters of Bristol Bay around the WISGS support a diverse group of marine mammals. Of these, Pacific walrus is the best known and locally abundant inhabitant within the WISGS. The walrus haulout at Round Island is one of four major terrestrial haulouts in Alaska. Walrus return to these haulouts every spring as the ice pack recedes northward, hauling out at these beach sites for several days between feeding forays. The number of walrus using the island fluctuates significantly from year to year, however, up to 14,000 walrus have been counted on Round Island in a single day.

  • Historic annual peak and recent daily counts compared to historic averages are summarized here (PDF 186 kB).

Steller's sea lions are common throughout the WISGS between May and Novermber with several hundred regularly hauling out at East Cape on Round Island. They can frequently be seen swimming offshore at Round Island and observed from the haul out viewpoint. Sea lions also haul out on High and Crooked Islands and the Twins. Harbor seals are not as common as sea lions but can be found around most islands year round.

In April and May, gray whales (PDF 47 kB) can be numerous feeding in small pods offshore as they move northward on their annual spring migration. Orca (PDF 45 kB), humpback (PDF 48 kB), and minke whales have also been seen offshore. With a number of observations of Orca whale having been made over the years, many showing attacks on walrus.

Terrestrial Mammals

Red fox (PDF 47 kB) are abundant on Round, Summit, and Crooked islands. They are the primary mammalian resident on Round Island, and are regularly seen feeding on seabirds, eggs, chicks, voles, shrews, and beach-cast carcasses. There are several active dens on the island, and fox kits may be observed during summer months. Small mammals, cached eggs, and perhaps walrus carcasses provide a winter food supply for these year-round residents.

Small mammals such as shrews (PDF 38 kB) and voles (PDF 46 kB) are also common on Round Island and likely inhabit the other larger islands of the WISGS. Black Rock and the Twins likely do not support any terrestrial mammals as habitat is limited.


Bird species inhabiting Round Island are relatively well known. Round Island staff has compiled seasonal lists since 1985, documenting over 105 species. Birdlife on the other islands are less well known as they are rarely visited. Crooked Island has 58 species documented, however, it may support more than Round Island due to its more diverse habitats, proximity to the mainland, and larger area.

Each summer, thousands of seabirds return to the WISGS to nest and raise their young. Nearly 250,000 seabirds nest at the Round Island colonies. This includes approximately 150,000 common murres, 70,000 black-legged kittiwakes, 1,250 pelagic cormorants, parakeet auklets, horned and tufted puffins (PDF 61 kB), pigeon guillemots, and glaucous-winged gulls (PDF 62 kB). Approximately 135,000 more seabirds nest on the Twins, and the other islands of the Sanctuary also support sizeable seabird colonies.

Round Island is also home to numerous other seabird, passerine, raptor, duck, and shorebird species. Ravens are a common resident on Round Island often preying heavily on seabirds and seabird eggs.


No freshwater fish species are known to inhabit the streams on Round Island or any of the other islands within the WISGS. While the islands remain relatively unexplored for fish presence the steep terrain and streams that typically enter the sea over falls impassible to anadromous fish make fish presence less likely. Only Crooked Island has a number of low gradient streams and lagoons that may support resident or anadromous fish. Black Rock and The Twins are very small rocky islands and do not have any known freshwater bodies.

While the islands themselves may not have any fish, the marine waters around these islands are teaming with fish and marine life. All five species of salmon (Chinook, Coho, chum, sockeye and pink) pass through these sanctuary waters. Marine waters from the Nushagak Peninsula to Hagemeister Strait are one of the principal spawning areas of Pacific herring in Bristol Bay. Yellowfin sole are found in waters to the southeast of Round Island and Capelin are known to spawn on the western shore of Crooked Island. Marine fish species inhabiting sanctuary waters are an important food source for the Steller sea lions and seabirds that inhabit the islands.


The Alaska Department of Fish and Game, the US Fish and Wildlife Service, the US Geological Survey (Biological Research Division), the National Park Service, the Alaska Department of Natural Resources, University of Alaska, Qayassiq Walrus Commission, Eskimo Walrus Commission and Bristol Bay Native Association have all collaborated on Round Island research projects.

Annual projects include the monitoring of Pacific walrus numbers, disturbance impacts to the haulout, Steller sea lion numbers, seabird populations and productivity, and other aspects of the island's ecology. Additional information on these annual Round Island monitoring programs can be accessed through annual management reports on the More Resources page.

Additional reading on Round Island specific research projects can be accessed through the More Resources page under the heading WISGS Research Reports.