The ISRP finds that objectives 1 and 2 meet scientific review criteria, but objective 3 does not meet criteria for the reasons described below.

Smolt travel time and survival estimates from this study will contribute to filling data gaps identified in the Adaptive Management Implementation Plan and could play an important part in recovery of ESA-listed Snake River sockeye salmon by increasing understanding of juvenile sockeye salmon migrations across multiple years. Relationships between the proposed work and the AMIP, 2008 BiOp, MERR, and several specific Fish and Wildlife Program recommendations are described in the proposal.

Objectives for the PIT-tagging and radio-tagging portions of the study (Objectives 1 and 2) are well defined. Monitoring of radio-tagged fish at various locations along the migration route will allow estimation of survival rates over different river reaches. Comparison of release-to-Lower Granite Dam survival rates for radio-tagged and PIT-tagged fish will provide a test for differential tagging effects. This project should be ranked as high priority, because little is known of the migration behavior and survival rates of juvenile sockeye in the basin. A few suggestions for further development of the study plan are:

1) The rationale for desired precision values leading to a target sample size of 400 radio-tagged fish should be presented. Sample size adequacy for investigation of fish size, origin, and release location as covariates in the travel time and survival analyses should be investigated.

2) The sampling plan proposes survival estimates for 25 contiguous river reaches between release points and Lower Granite Dam. This may be overly ambitious, particularly for the first year of the study. Are there important questions that can be answered only at a high level of resolution? Anecdotal observations suggest that predation mortality may be high in the first stage of the migration, soon after the smolts are released. If so, might it be most efficient for the study to initially use fewer and longer reaches, emphasizing study of the effects of alternative smolt release strategies on survival in the uppermost reach?

In contrast to Objectives 1 and 2, Objective 3 – to characterize the migratory behavior of juvenile Snake River sockeye salmon using otolith microchemistry – was not well explained or justified. The intent of this objective is unclear, except for a statement (p. 6) that “we will reconstruct downstream migration by using chemical signatures reconstructed across otoliths...” The proposed sample sizes for this work are very small, and would rely on collection of dead fish (not a representative sample of migrating fish) from dam bypass systems. Otolith microchemistry methods have been shown capable of identifying fish that have reared for some period of time in different watersheds, but juvenile sockeye migrate rapidly downstream from the upper Salmon River basin in large schools through waters of mixed origin. The ability of otolith microchemistry to differentiate between the migration histories of individual fish is, in this situation, problematic. It appears that the radio-tagging study would produce the desired information on travel times through different reaches more directly and with greater precision than the otolith microchemistry work. The ISRP’s recommendation is to not pursue the otolith microchemistry work at this time.

The ISRP finds that objectives 1 and 2 meet scientific review criteria, but objective 3 does not meet criteria for the reasons described below. Smolt travel time and survival estimates from this study will contribute to filling data gaps identified in the Adaptive Management Implementation Plan and could play an important part in recovery of ESA-listed Snake River sockeye salmon by increasing understanding of juvenile sockeye salmon migrations across multiple years. Relationships between the proposed work and the AMIP, 2008 BiOp, MERR, and several specific Fish and Wildlife Program recommendations are described in the proposal. Objectives for the PIT-tagging and radio-tagging portions of the study (Objectives 1 and 2) are well defined. Monitoring of radio-tagged fish at various locations along the migration route will allow estimation of survival rates over different river reaches. Comparison of release-to-Lower Granite Dam survival rates for radio-tagged and PIT-tagged fish will provide a test for differential tagging effects. This project should be ranked as high priority, because little is known of the migration behavior and survival rates of juvenile sockeye in the basin. A few suggestions for further development of the study plan are: 1) The rationale for desired precision values leading to a target sample size of 400 radio-tagged fish should be presented. Sample size adequacy for investigation of fish size, origin, and release location as covariates in the travel time and survival analyses should be investigated. 2) The sampling plan proposes survival estimates for 25 contiguous river reaches between release points and Lower Granite Dam. This may be overly ambitious, particularly for the first year of the study. Are there important questions that can be answered only at a high level of resolution? Anecdotal observations suggest that predation mortality may be high in the first stage of the migration, soon after the smolts are released. If so, might it be most efficient for the study to initially use fewer and longer reaches, emphasizing study of the effects of alternative smolt release strategies on survival in the uppermost reach? In contrast to Objectives 1 and 2, Objective 3 – to characterize the migratory behavior of juvenile Snake River sockeye salmon using otolith microchemistry – was not well explained or justified. The intent of this objective is unclear, except for a statement (p. 6) that “we will reconstruct downstream migration by using chemical signatures reconstructed across otoliths...” The proposed sample sizes for this work are very small, and would rely on collection of dead fish (not a representative sample of migrating fish) from dam bypass systems. Otolith microchemistry methods have been shown capable of identifying fish that have reared for some period of time in different watersheds, but juvenile sockeye migrate rapidly downstream from the upper Salmon River basin in large schools through waters of mixed origin. The ability of otolith microchemistry to differentiate between the migration histories of individual fish is, in this situation, problematic. It appears that the radio-tagging study would produce the desired information on travel times through different reaches more directly and with greater precision than the otolith microchemistry work. The ISRP’s recommendation is to not pursue the otolith microchemistry work at this time.

Fish utilized for this study will be produced and marked under project #2007-402-00. We will utlize fish marked with ad-clips and PIT tags from that project to conduct the survival estimates associated with this project during FY11. From FY12-FY14 we have requested PIT tags to mark additional hatchery and natural origin fish to estimate survival.

1. This data will be made available electronically. The data will be available upon request from the sponsor directly or through the PTAGIS database.

2. All data collected will be made available. Survival estimates will be produced and can be queried through the FIsh Passage Center or through DART and the raw data collected will be available the PTAGIS.