The Gulf of Alaska is the northernmost region of the North Pacific Ocean, bordering the south coast of Alaska. The Gulf’s shoreline stretches from the Alexander Archipelago at Cape Spencer to Kodiak Island and the Alaskan Peninsula. The coastline is deeply indented by various fjords and inlets and has a surface area of 592,000 square miles. The Gulf’s two largest inlets are Cook Inlet and Prince William Sound, with the Kenai Peninsula separating the two inlets and extending southeast toward Kodiak Island. The Copper and Susitna Rivers are the major fresh water tributaries into the Gulf of Alaska. Its major ports include Anchorage, Seward and Valdez, North America’s northernmost ice-free port. The Aleutian Low Pressure system dominates the Gulf’s climate. The steep mountains along this coastline capture much of the significant rainfall that occurs here, creating the third largest icefield in the world, with glaciers covering 20 percent of the Gulf of Alaska watersheds. The first non-native to chart this body of water was Captain James Cook, who entered the Gulf in 1778 on his search for the great Northwest Passage.

The northern Gulf of Alaska is one of the world’s most productive ecosystems, providing millions of dollars annually with its seafood extraction, tourism, and recreation industries. The complex biodiversity of the Gulf alone contains 287 known species of fish, 25 species of marine mammals, and 26 species of seabirds, and is home to more than half of Alaska’s human inhabitants.

The Gulf of Alaska supports one of the largest and most diverse populations of marine birds in the northern hemisphere. More than 100 million birds of over 100 species depend on Alaska marine ecosystems during some part of their life cycle. These include loons, grebes, and waterfowl, as well as typical marine birds such as shearwaters, gulls, and alcids. At least three-fourths of these species breed in Alaska, and the rest are visitors from a wide variety of locations throughout the Pacific Ocean. Some visitors are transequatorial migrants from as far away as Antarctica. Of the 25 species of marine mammals in the Gulf, some of the most commonly observed species are the gray whale, Northern sea lion, harbor seal, California sea lion, sea otters, orcas and humpback whales.