There are two ways to measure the contribution of yearling smolts to a Chinook population; The portion they contribute to the smolt outmigration or the contribution to the spawning population. I prefer the latter and believe it is more related to either the discussion of providing forage for orcas or their contribution to the adult returns.

The contribution to adults sampled on spawning grounds for some of the North Sound Chinook populations.

North Fork Nooksack springs average 29%
South Fork Nooksack springs average 38 %
Suiattle (Skagit basin) springs ranging from 20 to 85%
Upper Sauk springs ranging from 35 to 45%
Upper Cascade springs ranging from 10 to 90%
Lower Sauk summers average about 20%
Skykomish summers ranging from 16 to 20%
Snoqualmie falls ranging from 16 to 20%

The Snoqualmie falls stand as significantly different than the typical Green river Falls in not only the yearling contribution but also in spawning timing. They often spawn into December with a genetic differences from the Green River fish. Have to wonder if they might represent what the PS falls may have originally looked like prior to the swamping of central/South Sound systems with Green River falls.

Curt