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


Population viability analysis
Population Viability Analysis
This research was initiated by the Puget Sound Steelhead Technical Recovery Team to develop viability criteria for threatened Puget Sound steelhead and to support recovery planning of this species. It involves conventional population viability analysis (PVA) combined with decision support systems such as Bayesian Networks. These systems are parameterized with information on abundance, productivity, spatial structure, and diversity obtained from various sources, including PVAs of individual populations from time-series data of abundance, productivity, age structure, iteroparity, influence of resident fish on anadromous abundance, and influence of human activities such as hatchery production, harvest, and habitat alteration. The work will also focus on assessing status of these listed species every five years as part of NOAA Fisheries' coastwide status review updates for listed salmonids.

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.


population status assessment
methods to improve information on population status
population viability analysis


None associated


Species Oncorhynchus mykiss
rainbow trout, steelhead trout, syeelhead trout


Jeff Hard
Principal Investigator
Jim Myers