Populations of chinook, Oncorhynchus tshawytscha, and coho salmon, O. kisutch, from Northern California and four species of North American sturgeon were analyzed by horizontal starch-gel electrophoresis. The products of 53 gene loci from 27 enzyme systems were used to characterize the genetic structure of 35 groups of hatchery and wild chinook salmon. The distribution of specific alleles, cluster analysis based on genetic identities, analyses of gene flow, and gene diversity analyses indicated that groups of chinook salmon from the three major river drainages in California were genetically differentiated. The products of 45 gene loci from 21 enzyme systems were used to characterize the genetic structure of 27 groups of coho salmon. Most of the observed genetic variation was due to rare alleles occurring in only a few groups of salmon. No obvious association of specific alleles with geographic area was observed and the low level of genetic variability made patterns of genetic structure or associations among the groups of coho salmon difficult to determine. The application of biochemical-genetic analyses to the management of chinook and coho salmon fisheries was addressed. A comparison of hatchery groups of chinook and coho salmon with wild groups in the same area revealed that hatchery stocks generally reflect the genetic structure of the local populations. The genetic differentiation of chinook salmon by drainage could provide fishery scientists with a means to identify specific groups of chinook salmon. The application of this technique to manage coho salmon populations is problematic at the present given the seemingly random distribution of alleles and the low levels of genetic variability. The products of seven gene loci were used to identify hybridization between chinook and coho salmon in a collection of salmon from a tributary to the Trinity River. The implications of a group of hybrid fish in the wild were discussed in terms of genetic resource conservation and disease transmission. The products of 20 gene loci were used to characterize the genetic structure and relationship of four species of sturgeon: Acipenser transmontanus, A. medirostris, A. fulvescens, and A. brevirostrum. Fixed allelic differences existed among the four species at several gene loci and each species could be unambiguously identified by its genetic profile.