Prized North Pacific food and sport fish (Oncorhynchus tshawytscha) of the salmon family. The average weight is about 22 lbs (10 kg), but individuals of 50–80 lbs (22–36 kg) are not unusual. Chinook salmon are silvery, with round black spots. In fresh water they are found from the Amur River of Asia northward and, across the Bering Sea, southward to the Sacramento River of North America. Their range in the open ocean extends farther south. During spring spawning runs, adults swim as far as 2,000 mi (3,200 km) up the Yukon River, spawn, and then die. Young chinook salmon enter the sea when one to three years old. They were successfully introduced into Lake Michigan, creating a new sport fishery after the virtual elimination of lake trout by sea lampreys in the mid 20th century.