Migratory Chinook salmon crowd American River shallows near Sailor Bar. The giant fish die soon after breeding. Armies of gulls await easy pickings.

SACRAMENTO, CA (MPG) - Endangered Chinook salmon are now running in full force.

Fall/winter migration peaks for the giants before the new year. Fish that hatched in the American River or were artificially bred at Nimbus Fish Hatchery reach adulthood by their third year. Cool fall river temperatures spur a mass homecoming from the Pacific.

To reproduce, the behemoths seek home waters and mates. Spawning occurs in gravel beds below where Nimbus Dam blocks the up-river path.

Some Chinook males weigh more than 50 pounds and can measure up to four feet. As they traverse riffles, much of their bodies are exposed. Hooked profiles and toothy jaws are clearly visible. Thrashing, churning and full-body leaps from the water are common phenomenon.

Battered by their long swim, females use waning tail strength to scoop nests in gravel shallows. Eggs are released, fertilized and buried. Male and female spawners die soon after mating; their rotting bodies contribute a winter buffet for river scavengers.

The Chinook run is closely followed by a similar steelhead migration. In an effort to revive decreasing salmonid numbers, fishing is banned in much of the American River during breeding seasons.

The best places to observe Chinook and steelhead migrations include River Bend (Rancho Cordova), Ancil Hoffman Park (Carmichael), Gold River, Sailor Bar and Nimbus Basin.