In Asia the major sockeye producing system is the Kamchatka Peninsula in Siberia. O. nerka spawn in many different habitats. Anadromous lake type sockeye spawn in the inlet or outlet of nursery lakes where upwelling highly oxygenated water occurs with optimal gravel and sand for spawning. Sockeye may forgo the extended freshwater rearing. As adults, O. nerka , migrate upstream the area of their birth during August and September.
Males generally arrive before females.
Upon arrival, the female builds a nest, redd, by cleaning gravel in an area of the stream or lake bottom. For anadromous sockeye the average fecundity is about 2,000 to 2,400 eggs per female. Females may produce up to 5,000 eggs depending on the size, age, and health of the fish. Nonanadromous kokanee have a fecundy of 200 to 300 eggs per female. Incubation time can vary greatly depending on the temperature of the water and condition of the redd.