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  • Evaluate the reproductive success of hatchery and wild Chinook salmon in the Wenatchee River


Northwest Fisheries Science Center (NWFSC) Conservation Biology CB - Genetics and Evolution


Wenatchee Spring Chinook Reproductive Success
Evaluate the reproductive success of hatchery and wild Chinook salmon in the Wenatchee River
This project addresses a key uncertainty for evaluating whether hatchery supplementation programs have a net positive contribution to recovery of listed populations. Specifically, what is the relative reproductive success of naturally spawning hatchery fish and what are causes of poor reproductive success of hatchery fish? We are addressing these questions by focusing on the spring Chinook salmon in the Wenatchee River, part of the endangered Upper Columbia River spring Chinook salmon ESU. Our 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, we obtain an estimate of the relative reproductive success (RRS) of the hatchery origin fish. 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 we have sampled 10 years of adults and 8 years of smolts. In several papers and reports generated by this project, we have reported on the RRS of spawners sampled in 2004-2007, and 2010, and have found that spawning age, size, and location, in addition to hatchery/wild origin, are important co-factors explaining variation in reproductive success. This has been a highly influential study that addresses a critical uncertainty identified in both recovery plans and biological opinions and has had strong support from the West Coast Regional Office.

Research Themes

Recovery and rebuilding of marine and coastal species
The Pacific Northwest is home to several iconic endangered species, including Pacific salmon and killer whales, and several rockfish species. Mandates such as the Endangered Species Act, MagnusonStevens Act, and the Marine Mammal Protection Act, grant NOAA Fisheries the authority to manage the recovery of depleted species and stocks. The NWFSC contributes to species recovery through research, monitoring and analysis, providing NOAA managers and regional stakeholders the tools and information they need to craft effective regulations and develop sustainable plans for recovery.

Research Foci

Characterize the population biology of species, and develop and improve methods for predicting the status of populations
To evaluate species status and recovery, it is necessary to understand key aspects of the population biology of the species in question. This includes basic information on abundance, age structure, recruitment, spatial distribution, life history and how the species interacts with its ecosystem. For some recovering species, including most overfished groundfish stocks, many ESA-listed Pacific salmon stocks, and high profile species such as Southern Resident killer whales, this basic information is often reasonably well understood. For other recovering species, such as Pacific eulachon and some ESA-listed rockfish species, even basic information (e.g. stock abundance) is unknown. Even for well-studied species, key information on survival rates for critical life stages and how the environment affects these vital rates is lacking. Without basic information on species dynamics, achieving other goals such as quantifying relationships between human activities and species recovery or even knowing if species recovery goals are being met will not be successful. The NWFSC, in partnership with regional stakeholders, including states, tribes and industry, is conducting research to collect and monitor critical demographic information for recovering species.
Evaluate the effects of artificial propagation on recovery, rebuilding and sustainability of marine and anadromous species
Artificial propagation has the potential to provide benefits both to species recovery and to seafood sustainability. Artificial propagation also poses risks to wild species and ecosystems. In the past, the use of artificial propagation has been an important risk factor for several threatened and endangered species, particularly Pacific salmon. Assessing the effects of artificial propagation is complicated by the fact that programs vary widely in size, rearing practices, and goals. The NWFSC conducts critical research on the influence of artificial propagation on population dynamics, growth rate, ecology of infectious disease, and the evolutionary fitness of wild fish and other marine organisms. Results of this research are needed to support the recovery of fish populations and have been especially valuable in providing critical information for recent, larger scale habitat restoration activities such as the Elwha Dam removal. NWFSC will continue to conduct science that informs the discussion about whether to allow fish to recolonize naturally after barrier removal, or to supplement populations with hatchery fish and on the impacts of aquaculture on fishing pressure and practices, and on the surrounding environment and ecosystem.


regulatory law
The culture of fish, aquatic invertibrates, and aquatic plants for the production of food
artificial propagation
research technique
genetic marker
research focus
all salmonids


None associated


Species Oncorhynchus tshawytscha
Chinook salmon, king salmon, spring salmon


Eric Iwamoto
Mike Ford
Principal Investigator