Figure 1. Smolt-to-adult return ratios (SARs).

Estimates of SARs for populations of spring and summer Chinook salmon from the (a) Snake River, (b) Mid-Columbia River, and (c) Upper Columbia River. SARs are presented as percentages without the inclusion of precocious males (jacks) and were acquired from the Fish Passage Center (http://www.fpc.org/). The run timing (sp  =  spring, su  =  summer) and the hatchery or river of origin are also included.