PROJECT BACKGROUND:
Since 2004, NOAA-NMFS and WDFW have collected and analyzed genetic data for the purpose of evaluating hatchery supplementation effectiveness. Specifically, what is the relative reproductive success of naturally spawning hatchery fish and what are causes of poor reproductive success of hatchery fish? NMFS and WDFW have addressed these questions by focusing on the spring Chinook salmon in the Wenatchee River, part of the endangered Upper Columbia River spring Chinook salmon ESU.

The study design uses genetic parentage analysis to assign progeny (sampled at both the smolt and adult life stages) to naturally spawning hatchery and wild origin fish. The progeny counts for each spawner are a measure of reproductive success, and by comparing the mean reproductive success of hatchery and wild spawners, an estimate of the relative reproductive success (RRS) of the hatchery origin fish can be obtained. A key part of the study is to include co-variables, such as age, size, run timing, spawning location, and spawning behavior, in the analysis so that the proximate causes of differences in RRS between hatchery and wild fish can be evaluated.

The study was initiated in 2004 and has involved an annual complete or near complete collection of the potential adult spawning population every year and collection of a sample of juvenile offspring every year. WDFW (in a separate contract under this project) conducts all of the field work, NMFS (under this contract) collects the genetic data, and both partners collaborate to conduct analyses and report results.

CURRENT CONTRACT:
The field data collection associated with this project ended in 2023. However, this project has been extended for two years (until 2/28/26) to provide adequate time to analyze project data, produce draft manuscripts for publication, and develop a complete, final dataset that will be archived on a publicly available server. The work conducted by NMFS under this contract will primarily focus on genotyping the last portion of the 2018 brood year (age five adults to be sampled in 2023), creating a database to permanently hold all ~20 years of genetic and field data, and developing and refining multi-generation pedigrees of the population that form the basis of fitness analyses. NMFS will also continue to collect and analyze whole genome sequence data from a subset of samples to directly evaluate genetic divergence between hatchery and natural salmon in this population. The final analyses and results will be written as several manuscripts to fully describe and document patterns of relative reproductive success for hatchery and natural Chinook salmon in the Wenatchee River and submitted for publication in a suitable scientific journal.

This is the final contract for NMFS in project 2003-039-00.