Juvenile Description: The CSS is participating with Lower Snake River Compensation Program (LSRCP), Idaho Power Company (IPC), Dworshak National Fish Hatchery, and the Smolt Monitoring Program (SMP) to PIT-tag a representative portion of the hatchery spring/summer Chinook, hatchery summer steelhead, hatchery sockeye, and hatchery subyearling fall Chinook production originating above Lower Granite Dam and to assign these fish as Monitor Mode or Return-to-river Mode. Several entities cooperate with the CSS and participate in this endeavor. The CSS contributes a portion of the PIT-tags being used at each hatchery releasing spring/summer Chinook, fall Chinook, steelhead, and sockeye at locations above Lower Granite Dam. Spring/Summer Chinook releases include those tagged at Dworshak (~42,000) , Clearwater (~72,700), Rapid River (~52,000), McCall (~52,000), Pahsimeroi (~22,400), Sawtooth (~22,400), and Lookingglass (~42,000) hatcheries. Fall Chinook releases include subyearlings reared at Lyons Ferry Hatchery and acclimated at three release sites on the Snake and Clearwater rivers (above LGR): Captain Johns Rapids (26,000), Pittsburg Landing (26,000), and Big Canyon Creek (11,100). Summer steelhead releases include those tagged at Dworshak (~34,400), Clearwater (~18,100), Magic Valley (~34,800), Hagerman (~17,200), Niagara Springs (~22,700), Irrigon (~37,000) (releases in Grande Ronde and Imnaha rivers), and Lyons Ferry (~6,000) (release in Grande Ronde River) hatcheries. Sockeye releases include those tagged at Spingfield (~52,000) hatchery.
The CSS will be assigning the SbyC “Monitor-Mode” action for PIT-tagged spring/summer Chinook at Dworshak, Rapid River, McCall, and Lookingglass (Imnaha and Catherine Creek stocks) hatcheries, PIT-tagged fall Chinook at Captain Johns, Pittsburg Landing, and Big Canyon Creek acclimation ponds, PIT-tagged steelhead at Dworshak, Clearwater, Magic Valley, Hagerman, and Niagara Springs, and PIT-tagged sockeye at Springfield hatchery. SbyC “Monitor-Mode” pre-assignments for the other hatchery fish are conducted directly by their associated state agencies. The CSS will also be making the SbyC “Monitor-Mode” pre-assignments for wild Chinook and wild steelhead PIT tagged by the state fishery agencies of Idaho and Oregon and tribes of the Umatilla, Nez Perce, and Shoshone-Bannock.
Smolt-to-Adult Ratio: All of the PIT-tagged fish from the CSS are used to estimate SARs. For Snake River spring/summer Chinook, fall Chinook, steelhead, and sockeye, the CSS provides estimates of overall SARs, as well as route-specific SARs (i.e., transported vs. in-river migrants).