Cowlitzfisherman -

Another great question -

To track the status of a system in relation to MSH some measure of the escapement is needed. This can be achieved from dam counts or spawning surveys. Clearly that can not be done in season easily so generally managers would need to rely on information from recent years to forecast the likely upcoming run size.

Estimates of past exploitation requires both the escapement piece as well as an estimate of catch, this would be commereical reports, creel census, and other punch card information.

Tight lines
Smalma