Historically there were multiple salmon runs of several different species throughout the American River drainage and all the other tributaries of the Sacramento River. Mining activities in the late 1800s decimated these fish, but aggressive efforts by state and federal fish and game agencies have restored many runs to self-sustaining populations.

The king salmon (Chinook) run has been particularly strong in the lower American in recent years and is sustained by an extensive hatchery program at the dam. These 10- to 20-pound fish begin to enter the river in August. In August and September and into the beginning of October, these bright and aggressive fish are fresh from the salt. They, too, are perfect Spey-rod fish, eager to take a brightly colored fly swung across their lie. Nine- and ten-weight rods, sinking lines, and salmon flies such as chartreuse or orange Comets work well.

King salmon in the 10- to 20-pound range enter the American in August and continue to arrive through October.

The salmon spawn begins in earnest in October and the fish lose interest in feeding as the spawn progresses into December. The upper five miles of the river are closed to all fishing from November 1 to December 31 during the salmon spawn.

In the nationwide fish transplanting that began in the late 1800s, California gave the rest of the world rainbow trout from the McCloud River and Sonoma Creek. In return, San Francisco Bay received two superb fly-rod fish from the East Coast: the American shad in 1871 and the striped bass eight years later. The Bay, with its vast delta and many rivers running into it, has proven to be a great environment for these fish.