The green bar (“With Suppl.”) shows actual age-4 returns of wild/natural (unmarked) and CESRF (marked) fish to the Yakima R. mouth since age-4 CESRF fish began returning in 2001. The yellow bar (“Without Suppl.”) shows what estimated returns would have been if there was no CESRF and broodstock had instead been allowed to spawn in the wild and returned at the same rate as wild/natural fish. 2001-2004 are all straightforward F1 comparisons. However, beginning with 2005, F2 fish begin to complicate this comparison. In 2005, the green bar (“With Suppl.”) represents the unmarked age-4 progeny of WW, WH, HW, and HH crosses which spawned in the wild in 2001, plus the marked CESRF age-4 returns from 2001 brood. The 2005 yellow bar (“Without Suppl.”) represents the estimated return of age-4 fish in 2005 if the wild spawning escapement in 2001 had been the estimated wild return without supplementation that year (~7,100) plus brood collection (595) and all of these fish spawned in the wild and returned at the same rate (0.48; see next slide) as we calculated for natural spawners in the upper Yakima for the 2001 brood. Average benefit from supplementation ~ 72.5%.