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  • Project to study alternative life history types of fall Chinook based on otoliths


Northwest Fisheries Science Center (NWFSC) Fish Ecology FE - Ecosystem Analysis


Fall Chinook otolith
Project to study alternative life history types of fall Chinook based on otoliths
This project describes ongoing work by scientists in FE Ecosystem Analysis and EFS Environmental Chemistry programs to identify natal and rearing locations, reconstruct life history strategy, and evaluate juvenile performance of adult Snake River fall Chinook salmon. Due to dramatic declines in its abundance, Snake River fall Chinook salmon was listed as threatened under the Endangered Species Act. Management of Snake River fall Chinook salmon has been hindered by a great deal of uncertainty regarding key aspects of the population. In particular, the existence of an overwintering behavior in a portion of the population has complicated estimates of survival through the hydropower system. Further, differential detectability of redds has limited the ability to accurately develop run reconstructions. Effective management of Snake River fall Chinook salmon will require an understanding of the details of their early life-history, including where juveniles hatch and rear, the proportion of juveniles that exhibit the yearling strategy, when they initiate downstream migration, and estuarine residence time. In this project we investigate early life history movement and performance of Snake River fall Chinook salmon by using microchemistry and microstructure of otoliths sampled from juveniles and adults. Results from this study are intended to help inform recovery planning including future habitat restoration and conservation efforts in the Snake River Basin and Columbia River.

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.
Develop methods to use physiological, biological and behavioral information to predict population-level processes
Understanding the biological processes occurring within organisms is a powerful way of understanding how environmental changes affect those organisms. Genetics, developmental, physiological and behavioral studies all provide important information for effective species recovery and rebuilding. Integrating this information into models is vital to predict how populations will respond to natural or human perturbations, and to assess the constraints to stock rebuilding efforts. For example, data on thermal tolerance and physiological responses to temperature can be used to explore changes caused by shifts in climate on reproductive behavior and productivity, viability, movement, habitat selection, and population dynamics. Similarly, data on contaminants that impact physiological processes (immune system, growth, development, reproduction, and general health) are critical in determining how these compounds affect population dynamics. Data on biological responses of organisms to ocean acidification are useful for understanding how acidification may affect individual development and survival. The NWFSC collects such information for several species that are of concern, targets of fisheries or otherwise important for overall ecosystem function. NWFSC scientists will continue to expand current efforts and develop methods to incorporate physiological, biological and behavioral data into population models in order to predict population-level processes from these individual level data.


balance organ used to model growth and movement


None associated


Species Oncorhynchus tshawytscha
Chinook salmon, king salmon, spring salmon


Paul Chittaro
Internal Collaborator
Richard Zabel
Principal Investigator