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 the tagging study of juvenile life history of Snake River fall Chinook salmon, Project 200203200 in association with BPA contract requisition numbers CR-85326 (USGS), CR-85327 (USFWS) and CR-85438 (PNNL).

PROJECT OBJECTIVES

1. Develop RM&E Method and Designs – Develop the statistical study plan for the tagging study by Project 200203200.  A statistical synopsis will be developed describing the release-recapture study design, parameter and variance estimators, and tests of assumptions, as well as sample size 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 2007 radio-tag (RT) and acoustic-tag (AT) data generated by Project 200203200.  Compare juvenile fall Chinook salmon migration behavior (e.g., travel time distribution) to hydraulic data from radio, acoustic, and PIT tags.  Evaluate assumptions and limitations of estimating survival by (1) Cormack-Jolly-Seber (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 – Develop statistical models to calculate SAR that incorporate the reservoir-type life history, based on the alternative tagging data generated from Project 200203200.  Conduct a sensitivity analysis 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.  Determine how auxiliary information from acoustic tags could be used to provide bias corrections to the large PIT-tag studies currently used to study transportation effects.  Identify needs from future tagging studies to accurately estimate SAR for Snake River fall Chinook salmon.

4. Reporting – Contribute written description of statistical analyses to the annual project report for Project 200203200.  These sections will include material 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.