willametteriveroutlaw,

Sounds like broodstock hatchery fish to me.
Sure you were reading the correct report?
I didn't remember the Clack being in that particular report.

Using the geographic groupings described earlier, each population was assigned a corresponding
value for the variable (Gr). The value for this dummy variable was .-1. if the population
belonged to the Snake region, .1. if the population belonged to the coastal region, and a value of .0. if the population belonged to either of the other two regions. A dummy variable was also
used to represent the type of hatchery broodstock (Br). The value for Br was .1. if the hatchery
fish returning to the basin were predominately from broodstocks developed from wild fish also
from the same basin. All other populations (whether or not they had hatchery programs) were
given a value of .0. for the Br variable. For both dummy variables, the number of values was
purposely set to one less than number of possible categories in order to help avoid
multicollinearity. Prior to regression analyses, those data points for which the value for Ln(R/S)
deviated from the mean by more than 3 standard deviations were discarded.

Genetic differences may arise from the common situation that returning hatchery fish are the offspring of substantially fewer parents than is the case for wild fish returning to the same basin. For example, approximately 160 fish are used annually as broodstock for the North Umpqua summer steelhead hatchery program. In contrast, the number of wild fish that spawn naturally in the North Umpqua basin is typically greater than 3,000 fish (Appendix 1). Therefore, the genetic base for the hatchery return is approximately 80 families, whereas for the wild fish it is roughly 1,500 families.