(Oncorhynchus tshawytscha) prized North Pacific food and sport fish of the family Salmonidae. It weighs up to 60 kg (130 pounds) and is silvery with round black spots. Spawning runs occur in spring, adults swimming as far as 3,200 km (2,000 miles) up the Yukon. Young chinook salmon do not enter the sea until they are one to three years old. The chinook salmon was introduced into Lake Michigan of the U.S. Great Lakes with conspicuous success, creating a new sport fishery there after the virtual elimination of lake trout by sea lampreys.