The Chinook salmon /ʃɪˈnʊk/ (Oncorhynchus tshawytscha) is the largest species in the Pacific salmon genus Oncorhynchus. The common name refers to the Chinookan peoples. Other vernacular names for the species include king salmon, Quinnat salmon, spring salmon, chrome hog, and Tyee salmon. The scientific species name is based on the Russian common name chavycha (чавыча).Historically, the native distribution of Chinook salmon in North America ranged from the Ventura River in California in the south to Kotzebue Sound in Alaska in the north.In 1967, the Michigan Department of Natural Resources planted Chinook in Lake Michigan and Lake Huron to control the alewife, an invasive species of nuisance fish from the Atlantic Ocean. Alewives then constituted 90% of the biota in these lakes. Coho salmon had been planted the year before and the program was a success.The Chinook is blue-green, red, or purple on the back and top of the head, with silvery sides and white ventral surfaces. It has black spots on its tail and the upper half of its body. Chinook have a Black gum line which is present in both salt and freshwater. Adult fish range in size from 24 to 36 in (61 to 91 cm), but may be up to 58 in (150 cm) in length; they average 10 to 50 lb (4.5 to 22.7 kg), but may reach 130 lb (59 kg). In the Kenai River of Alaska, mature Chinook averaged 16.8 kg (37 lb). The current sport-caught world record, 97.25 lb (44.11 kg), was caught on May 17, 1985, in the Kenai River (Kenai Peninsula, Alaska). The commercial catch world record is 126 lb (57 kg) caught near Rivers Inlet, British Columbia, in the late 1970s.Chinook may spend one to eight years in the ocean (averaging from three to four years) before returning to their home rivers to spawn. The salmon also undergo radical morphological changes as they prepare for the spawning event ahead. All salmon lose the silvery blue they had as ocean fish, and their colour darkens, sometimes with a radical change in hue. Salmon are sexually dimorphic, and the male salmon develop canine-like teeth and their jaws develop a pronounced curve or hook, called a “kype“. Studies have shown that larger and more dominant male salmon have a reproductive advantage as female Chinook are often more aggressive toward smaller males.The total North Pacific fisheries harvest of the Chinook salmon in 2010 was some 1.4 million fish, corresponding to 7,000 tonnes; 1.1 million of the fish were captured in the United States, others were divided by Canada and Russia.The worlds’ largest producer and market supplier of the Chinook salmon is New Zealand. Marketed as King salmon, in 2009, New Zealand exported 5,088 tonnes of salmon equating to a value of NZ$61 million in export earnings. For the year ended March 2011, this amount had increased to NZ$85 million.Nine populations of Chinook salmon are listed under the U.S. Endangered Species Act as either threatened or endangered.The Chinook salmon is spiritually and culturally prized among certain First Nations peoples. Many celebrate the first spring Chinook caught each year with “first-salmon ceremonies”. While salmon fishing is still important economically for many tribal communities, the Chinook harvest is typically the most valuable.