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Review of Long-Running Salmon Survival Study:
Smolt-to-Adult Return Goals Should be Reassessed

by Staff
Columbia Basin Bulletin, October 26, 2012

A recently completed independent scientific review gave high marks to the most recent annual report on the long-running Comparative Survival Study, saying it is "well organized and well written" and presents data that is "valuable" for managers attempting to improve Columbia River conditions for imperiled salmon and steelhead.

"As the dataset includes more years and a wider range of environmental conditions, the ability to address how the river environment affects juvenile salmon migration rates and survival continues to improve," the Independent Scientific Advisory Board's "Review of the Comparative Survival Study's Draft 2012 Annual Report" says. "The long time series in survival rates by species, hatchery and wild stocks, and watersheds are valuable in this regard."

The ISAB in its review also suggests topics for "consideration for the region as a whole." As an example, the review described the need for a reassessment of whether smolt to adult return (SAR) goals set out by the Northwest Power and Conservation Council's fish and wildlife program "are sufficient to meet salmonid species conservation, restoration, and harvest goals."

The Council and others in the region are amidst a battle to revive depleted salmon and steelhead and other fish and wildlife. A total of 13 Columbia-Snake river salmon and steelhead stocks are listed under the Endangered Species Act.

Those issues laid out by the ISAB stem in part come from information portrayed in the draft Fish Passage Center annual CSS report

"These overarching issues, included in this message below, are related to material presented in the draft 2012 CSS Annual Report, but the topics are not specifically limited to consideration by the CSS team," the ISAB report says.

The Oct. 15 ISAB review can be found at:

The draft 2012 "Comparative Survival Study (CSS) of PIT-tagged Spring/Summer/Fall Chinook, Summer Steelhead, and Sockeye," can be found at:

The CSS report was prepared by the Comparative Survival Study Oversight Committee and Fish Passage Center. Participants include staff from the FPC, the Columbia River Inter-Tribal Fish Commission, the U.S. Fish and Wildlife Service, the Oregon and Washington departments of fish and wildlife and the Idaho Department of Fish and Game. Project leader is Michele DeHart, FPC manager.

The FPC staff provides technical services to the fish agencies and tribes impacted by the operation of the Federal Columbia River Power System, a system of dams operated by the U.S. Army Corps of Engineers and Bureau of Reclamation. The FPC is funded by the Bonneville Power Administration through the NPCC's fish and wildlife program.

The ISAB was formed by NOAA Fisheries, Columbia River Indian tribes and the Council to provide independent scientific advice and recommendations regarding scientific issues that relate to the respective agencies' fish and wildlife programs.

Chapter 4 of the draft annual CSS report "describes SAR Program goals as being for spring/summer chinook and thus not tailored for other species, races, and age of smolts," the ISAB report says. "These SAR goals should be broken out by species, race, and age at smoltification rather than one goal across all species. Coho, fall chinook, and steelhead have different juvenile life histories, and it is likely inappropriate to generalize SAR objectives for viability across these species.

"The analyses in Chapter 5 lead to the important conclusions that overall SARs for Snake River subyearling fall chinook are 'well short of the NPCC goal of 4 percent SAR needed for recovery' and that there is little or no benefit to transport.

"But given that fall chinook migrate as subyearling smolts (whereas spring/summer Chinook migrate as larger, yearling smolts), the NPCC's 2-6 percent SAR objectives may be higher than needed to meet conservation, restoration, and harvest goals for fall chinook," the ISAB review says. "As with other species, the NPCC (2009) SAR objectives should be updated to specify the critical points in the life cycle where smolt and adult numbers should be estimated and to identify ESU-specific SARs necessary for survival and recovery."

In the ISAB review's "General Comments for CSS Consideration, it says that "a topic of much interest that is related to the 2012 CSS Annual Report is the relationship between proportion of spill and juvenile survival.

"The topic may be framed by considering a conclusion from the FPC's History of Spill Report,1 'Increasing proportion of spill provided for fish passage at hydroelectric projects has resulted in higher juvenile spring/summer chinook, fall chinook, sockeye and steelhead survival and faster juvenile fish travel time through the FCRPS.' The ISAB considers this conclusion to be a strong hypothesis worthy of further investigation in the context of reviewing the draft 2012 CSS Annual Report."

The review lists nine ISAB comments for CSS consideration in producing the year's final report and/ future reports.

"An overarching comment is that connections of the migration and survival with larger ecological concerns should be emphasized more. It would be beneficial to increase collaboration with researchers working on other species, food webs, habitat, physiology, contaminants, and disease. Such combined studies might give added insights into mechanisms causing the observed temporal patterns in migration and survival," the ISAB review says.

Amendments to the Council's Columbia River Basin Fish and Wildlife Program approved in 2009 called for a regular system of independent and timely science reviews of the FPC's analytical products, including evaluations of the CSS draft annual reports.

"The Comparative Survival Study (CSS; BPA Project 199602000) began in 1996 with the objective of establishing a long-term dataset of annual estimates of the survival rate of generations of salmon from their outmigration as smolts to their return to freshwater as adults to spawn (smolt-to-adult return rate; SAR)," according to the draft 2012 annual CSS report completed Aug. 31.

"The study was implemented with the express need to address the question of whether collecting juvenile fish at dams, transporting them downstream of Bonneville Dam (BON) and then releasing them was compensating for the effect of the Federal Columbia River Power System (FCRPS) on the survival of Snake Basin spring/summer Chinook salmon that migrate through the hydro system."

The purpose of the FPC annual report is to document the hydro system operations, environmental conditions and the resulting fish passage characteristics that occurred during the year. It also consolidates other information that is helpful in describing the year in terms of Columbia Basin salmon and steelhead passage through the hydro system.

It also "documents prevailing fish passage management concerns, questions and decisions for that year by the fishery managers and hydro system managers," the most recent CSS annual report says. The overall objective of the annual report is to provide a historical reference for each year to provide a basis for future fish passage mitigation discussions, and a base reference for future analysis of adult returns.

The annual report's prime focus is the Smolt Monitoring Program, which is designed to provide a long-term consistent and continuous juvenile salmon and steelhead passage characteristics data time series. It is updated daily and provided to fishery managers to inform their discussions of fish passage management. This includes juvenile survival, passage timing, and passage indices by species, dissolved gas trauma monitoring, hatchery releases and fish condition. In addition this report summarizes the environmental passage conditions, flow, spill, water temperature, project operations, studies and research that occurred and that may have affected passage conditions.

Review of Long-Running Salmon Survival Study: Smolt-to-Adult Return Goals Should be Reassessed
Columbia Basin Bulletin, October 26, 2012

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