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Count the Fish by Government Accounting Office, GAO-02-612 Salmon and Steelhead Recovery Efforts

Based on paleolimnological and primary productivity models the historic adult escapement to Redfish Lake was 10,000 - 35,000. The paleolimnoligical work indicated that a peak of near 35,000 occurred around the early 1700's, and ranged from ten to mid twenty thousands prior to that time.

". . . clearly the risk of extinction is very high."

Snake River (SR) Sockeye are spring migrants with peak movement past Lower Granite Dam during May. An unknown proportion of the juvenile migration is transported from the Snake River collector projects. Studies at John Day and Wanapum dams with run-of-the-river unlisted Upper Colombia River (UCR) sockeye salmon found that the FGE (fish guidance efficiency) of juvenile sockeye salmon was lower than that of spring chinook salmon or steelhead. If this finding also applies to the Snake River Evolutionary Significant Unit (ESU), it is likely that a small proportion of the sockeye salmon outmigration is transported compared to those of spring/summer chinook salmon or steelhead. If transport rates are lower, it is likely that the total direct survival of this species is also less than that of other yearling migrants. Adult migration estimates 98% per project 85% for 8 projects - based on Upper Columbia River ESU.

Sockeye Salmon
p102of111
The abundance of SR sockeye salmon is so low that the risk of extinction is undoubtedly very high. Assuming that juvenile mortality in the action area is similar to that of other yearling migrants, transit through eight FCRPS (Federal Columbia River Power System) projects under the proposed action is likely to contribute to the ongoing high risk of extinction. Other factors also affect elements of critical habitat and thus contribute to this ESU's high risk of extinction, but the FCRPS is a significant factor. The risk is partially mitigated by a captive breeding program funded by the Action Agencies, providing some assurance that Snake River sockeye will not go extinct in the immediate future. However, long-term survival and recovery in the wild will require substantial increases in survival through the FCRPS and in other life stages.

A.6 Appendix A, p 81 of 92
Two estimates of total (direct and indirect) juvenile passage survival were included in both the base and the current matrices. Each represented an average of the 0.63 to 0.73 range of differential delayed mortality (D) estimates described in section 6.2. The high and low juvenile passage survival estimates differed only in the treatment of delayed mortality of non-transported fish.. Under the low delayed mortality assumption, non post-Bonnneville mortality of non-transported fish was attributed to the hydrosystem. Under the high delayed mortality assumption, post- Bonneville mortality attributed to the hydrosystem was the average of the PATH lambda-n estimates associated with D equals of 0.63 to 0.73. These estimates of mortality were .709 and .743, respectively.

Snake River Sockeye Chapt 4.1.12
The only remaining sockeye in the Snake River system are found in Redfish Lake, on the Salmon River. The nonanadromous form (kokanee), found in Redfish Lake and elsewhere in the Snake River basin, is included in the ESU. Snake River sockeye were historically abundant in several lake systems of Idaho and Oregon. However, all populations have been extirpated in the past century except fish returning to Redfish Lake. In general, juvenile sockeye salmon rear in the lake environment for 1,2, or 3 years before migrating to sea. Adults typically return to the natal lake system to spawn after spending 1,2,3, or 4 years in the ocean In 1910, impassable Sunbeam Dam was constructed 20 miles downstream of Redfish Lake. Although several fish ladders and a diversion tunnel were installed during subsequent decades, it is unclear whether enough fish passed above the dam to sustain the run. The dam was partly remove in 1934, after which Redfish Lake runs partially rebounded. Evidence is mixed as to whether the restored runs constitute anadromous forms that managed to persist during the dam years, nonanadromous forms that became migratory, or fish that strayed in from outside the ESU. NMFS proposed an interim recovery level of 2,000 adult Snake River sockeye salmon in Redfish Lake and two other lakes in the Snake River basin. The ESU contains less than 10 wild adults. Numbers are inadequate for a CRI type analysis, but clearly the risk of extinction is very high.

Related Pages:
Sockeye Salmon Captive Broodstock Program by Idaho Dept. of Fish & Game