Coho salmon are also refered to as silver salmon. They have powerful, streamlined bodies characteristic of other salmonid species. Juvenile silver salmon look similar to rainbow trout parr, but differ in having very narrow, vertical parr marks and an elongated anal fin. At sea, or in a freshwater lake, adult silver salmon have a metallic, bluish-green back, silver sides, and a white underside. Adult coho and chinook salmon, of the same size, can look fairly similar at sea. The silver salmon is differentiated from the chinook by having white gums around the teeth and spots on only the upper part of the caudal fin. The back of the silver salmon is also scattered with smaller spots from head to tail.
Silver salmon spawn in cool, freshwater streams with adequate flows. Once an appropriate site is located, the female uses her powerful tail to clear out a depression (redd) in the gravelly bottom. Eggs are deposited in the redd as one or more males fertilize them. The eggs are then lightly covered with gravel and allowed to incubate for 1 to 3 months, depending on water temperature. Juvenile coho remain in freshwater for 1 to 3 years before migrating to the ocean. The duration of this freshwater residence varies within, and between, watersheds throughout their range.
The coho is one of the larger Pacific salmons. The adult coho averages around 10 pounds throughout it's range.
