The Chinook salmon is the largest species of salmon and is native to the Pacific Ocean and rivers that flow into it. Chinook salmon are anadromous fish, meaning they are born in fresh water, migrate to the ocean where they grow and mature, and then return back to fresh water to spawn. When Chinook are in the ocean they are silvery in color with black spots on the upper half of their body. When Chinook salmon return to spawn, they begin changing colors. The longer they are in fresh water the more they change. In Idaho, by the time they spawn they can range anywhere from a yellowish-olive color to greyish-black. In states like Alaska, Chinook salmon will turn a reddish color before they spawn. One characteristic that anglers can use to identify a Chinook salmon from other salmon species is the entire inside of their mouth is black.
The size that Chinook salmon will obtain is largely dependent on how long they spend in the ocean. Chinook that spend one year in the ocean before returning to spawn are commonly referred to as “jacks” and average about 3-5 pounds in size. After two years in the ocean they average around 10-15 pounds, in three years 15-22 pounds, and after four years 25-35 pounds. The Idaho State record caught Chinook salmon weighed 54 pounds.