Biological and physical variables influencing survival and standing crops of juvenile salmon are treated by regression analyses to determine those variables of greatest significance. Stream flow in dry seasons as indicated by rainfall proved to be the most important single factor influencing survival from age 0+ to age I+ in the presence of such other variables as standing crops of other fishes and water temperatures. A Chi-square test indicated that the various species of fish present in Barrows Stream during the 6-year study reacted to electrofishing as though they were a single species. Indications are that construction of small water storage dams at appropriate sites in the headwaters of salmon nursery areas could increase survival and growth rate of juvenile salmon occupying the nurseries.