Figure 1. Map showing location of Snake River dams (with first date of operation), rivers, and hatcheries described in the text. 1 = Kalama Falls Hatchery; 2 = Bonneville Hatchery; 3 = Priest Rapids Hatchery; 4 = Lyons Ferry Hatchery; 5 = Hagerman Hatchery. Locations for Bonneville Dam and other Columbia River dams are also indicated.
Figure 2. Historical spawning habitat for spring-, summer-, and fall-run chinook salmon in the Snake River Basin.
Figure 3. Counts of adult fall chinook salmon at Lower Granite Dam since its completion in 1975. Estimates of the number of wild fish are obtained by subtracting estimated number of hatchery fish from the total. Based on data in Table 5; see text for discussion of estimation procedures.
Figure 4. Proportion of coded-wire-tag recoveries in different geographic areas for hatchery fall chinook salmon from the Snake River (Hagerman and Lyons Ferry Hatcheries) and the upper Columbia River (Priest Rapids Hatchery). Results are summarized by brood year, and all data are for zero-age (subyearling) releases (from Busack 1991c). See also Berkson (1991) and McNeil (1991) for additional treatments of these and other CWT data.
Figure 5. Mean monthly water temperatures over a 2-year period for the Snake River (Weiser, Idaho) and at Rock Island Dam on the upper Columbia River (from Utter et al. 1982).
Figure 6. Dendrogram showing clustering of pairwise genetic distance values (Nei 1978) computed for 21 polymorphic gene loci in chinook salmon from the Columbia River Basin. Modified from Waples et al. (1991), and based on published and unpublished data from NMFS and WDF. Run-time designations in parentheses are SU (summer), FB (fall "upriver bright"), and FT (fall "tule"); others are spring-run stocks. In general, clusters can be characterized by geography and run-timing: A-upper Columbia River summer- and fall-run; B-Snake River fall-run; C-lower Columbia River fall-run; D-Willamette River spring-run; E-Snake River spring- and summer-run; F-upper Columbia River spring-run; G-mid-Columbia River spring-run.
Figure 7. Time series of allele frequency data at six gene loci for fall chinook salmon from the Snake and upper Columbia Rivers, based on NMFS and WDF data summarized by Busack (1991b, Table 10). Old locus names (as used by Utter et al. 1982) are shown in parentheses below current names. Upper Columbia River data points are for wild samples from the Hanford Reach area and samples from Priest Rapids Hatchery; unweighted averages were used in combining multiple samples from the same year. Pre-1985 samples for the Snake River are for presumably wild fish collected at Ice Harbor Dam; later samples are from Lyons Ferry Hatchery. Two Lyons Ferry samples were analyzed in 1990; the open circle represents a sample of all untagged fish, and the open triangle represents the sample of returning CWT Lyons Ferry fish (primarily from the 1986 brood).
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