PROJECT OVERVIEW

Snake River Fall Chinook salmon are known to exhibit two types of juvenile life history:  an “ocean-type” life history in which juveniles enter saltwater as subyearlings, and a “reservoir-type” life history in which juveniles overwinter in the reservoirs and enter seawater as yearlings.  The variable life history of juvenile fall Chinook salmon may introduce bias into estimates of smolt-to-adult return (SAR) ratios and transport-inriver (T/I) ratios.  The size and nature of the bias are unclear, due to uncertainties about the proportion of fall Chinook that are destined to be reservoir-type, where reservoir-type fish cease seaward movement as subyearlings, the extent of seaward movement when the fish bypass systems and monitoring at dams are not operational, and the survival of reservoir-type fish both in the reservoirs and in the ocean.  Our mission is to develop statistical methods to assess the effect of the reservoir-type life history on estimates of SAR, and to develop a method of correcting life history-induced bias in SAR estimates.

The University of Washington’s contribution to this project is to provide statistical support to estimate the proportions of fish adopting the reservoir-type life history and the relative survival of such fish.  We will assist in developing the experimental design for the yearly tagging studies.  We will also compare migration behavior to hydraulic data gathered in the study.  Additionally, we will provide statistical methods to assess the bias in SAR introduced by the alternative life history and to determine whether auxiliary information from acoustic tags could be used to provide bias corrections to the large PIT-tag studies currently used to study transportation effects.


PROJECT GOAL

Provide statistical support to tagging study of juvenile life history of Snake River fall Chinook salmon, Project 200203200 in association with BPA contract requisition numbers CR-102996, CR-102995, and CR-102994.


PROJECT OBJECTIVES

1. Develop RM&E Method and Designs – Update the statistical study plan for the tagging study associated with Project 200203200.  Build upon the statistical synopsis from the previous year to reflect changes in study design and additional goals and tasks.  The updated statistical synopsis will describe the release-recapture study design, parameter estimators and variance estimators, and tests of assumptions, as well as sample size calculations and precision calculations.  The purpose of the synopsis is to assure that all study objectives can be accomplished validly and efficiently.  The synopsis will serve as guidance during data analysis.

2. Analyze/Interpret Data – Assist in analyzing the 2009 RT and AT data generated by Project 200203200.  Compare juvenile fall Chinook salmon migration behavior to hydraulic data from radio and acoustic tags.  Evaluate assumptions and limitations of estimating survival by (1) CJS using PIT-tag data, (2) CJS using RT/AT data, and (3) abundance estimates from the Lincoln-Petersen mark-recapture model.

3. Analyze/Interpret Data – Compare alternative methods to calculate SAR using tagging data from subyearling and yearling fall Chinook salmon.  Confirm the sensitivity analysis from previous years to assess the nature and magnitude of the bias introduced by the reservoir-type life history to SAR calculated using Lower Granite equivalents with the CSS modeling approach.  Write results in journal article.  Present results at regional fall Chinook workshop.

4. Reporting – Contribute written description of statistical analyses to the annual project report for Project 200203200.  These sections will include sections on statistical methods, results, discussion, recommendation, and literature cited, as well as tables and figures.  

5. Manage and Administer Project – Perform administrative responsibilities required for compliance with BPA program requirements including metric reporting, financial reporting (accruals), and development of annual statements of work.

6.  Produce Pisces Status Reports – Report on the status of milestones and deliverables in Pisces.