Laying and fertilizing eggs
Early in spawning, as many as 1200 eggs may be released into the nest, the number decreasing in subsequent nests. As they are released, current eddies in the depression pull most eggs downward into the nest to less turbulent water where sperm has settled and where they become lodged in the gravel.
Female covering eggs
As soon as the female has released her eggs, she instinctively covers them by moving upstream slightly and repeating her digging motions. This lifts gravel just above the nest, so that the current carries it into the depression. These “covering digs” increase in intensity until the nest has been filled. Often the males will leave the female, in search of another that is preparing a nest. The female moves upstream slightly and begins digging a new nest. Spawning can last for several days. Once the females have deposited their eggs, they defend their redds until they die, about a week later. Males remain sexually active longer, roaming the stream in search of late females.
Gradually, the scene turns from a frenzied expression of life to a pathetic scene of death. Carcasses beach on the gravel, line the bottom, float downstream, and hang up in roots and limbs. Survivors swim listlessly, often drifting with the current. The scavengers arrive – ravens, crows, eagles, gulls, bears, and others. Footprints appear in the river sand overnight. The smell of rotting flesh rises out of logjams.
As the drama of spawning quiets with the death of the adult fish, the patient observer of salmon can take heart in what the process has yielded. The littered bodies, dragged into the shrubs and partly eaten, feed the entire forest. And underneath those fresh mounds of gravel on the stream bottom, thousands of eggs are already growing. The salmon are very much alive.
From the “Adopt-A-Stream Foundation Field Guide to the Pacific Salmon,” by Robert Steelquist. We are grateful to Sasquatch Books for granting us permission to reproduce this description of salmon spawning.