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  • Recolonization of the Cedar River, WA by Pacific salmon


Northwest Fisheries Science Center (NWFSC) Fish Ecology FE - Watershed


Cedar River
Recolonization of the Cedar River, WA by Pacific salmon
The objective of this study is to quantify population, community, and ecosystem level changes as a result of salmon recolonization of the Cedar River, WA above Landsburg Dam. The dam was installed in 1901, blocking the upstream migration of adult salmon and steelhead from about 43 km of river habitat. A fish ladder was installed in 2003 to allow adult salmon passage. We collected baseline data on water chemistry, habitat, isotopes (periphyton, invertebrates, fish, riparian trees) and resident trout and sculpin populations in 2000-2002. These studies have been ongoing since 2000. A mark-recapture study in Rock Creek, the largest tributary available to salmon, was started in 2004 to quantify growth, movement, and survival of juvenile coho and resident trout.

Research Themes

Habitats to support sustainable fisheries and recovered populations
Healthy oceans, coastal waters, and riverine habitats provide the foundation for aquatic resources used by a diversity of species and society. Protecting marine, estuarine and freshwater ecosystems that support these species relies on science to link habitat condition/processes and the biological effects of restoration actions. The NWFSC provides the habitat science behind many management actions taken by NOAA Fisheries and other natural resource agencies to protect and recover aquatic ecosystems and living marine resources. The NWFSC also maintains a longstanding focus on toxic chemical contaminants, as a foundation for regional and national research on pollution threats to fisheries and protected resources.
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 relationships between habitat and ecosystem processes, climate variation, and the viability of organisms
Developing effective conservation and restoration strategies for species or populations requires a clear understanding of how ecosystem processes and climate change will influence the viability of organisms in the future. Key research needs include (1) evaluating the vulnerability of organisms and ecosystems to climate change and human impacts (e.g., fishing, pollution, land use), and (2) devising adaptation strategies that will help achieve conservation goals despite climate change and increasing human pressures. Understanding how climate change or trends in human impacts might influence organisms is based on an understanding of linkages between ecosystem processes, habitat conditions, and abundance, survival or demographics of organisms. This necessitates modeling influences of ecosystem processes on habitats and species, or developing models to examine influences of human pressures on population or ecosystem dynamics. With this foundation, vulnerability assessments can focus on understanding how interactions between climate change and human impacts influence vulnerability of species or populations. Adaptation strategies require knowledge of current conservation needs, predictions of how those needs might change as a result of climate change or future human impacts, and assessments of the robustness of alternative conservation strategies or techniques to climate trends.
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 effective and efficient habitat restoration and conservation techniques
Maintaining and re-establishing viability and sustainability of living marine resources requires conservation and rehabilitation or restoration of habitats upon which species depend. Common habitat restoration approaches and tech-niques often presume that habitats are static features of the environment, and that creation of stable habitats is a desirable restoration strategy. However, riverine, nearshore, and marine habitats are created and sustained by dynamic landscape, climatic, and oceanographic processes and biota are adapted to changing habitats that are within the range of natural variability. Hence, current restoration strategies often have limited success, in part because they fail to recognize larger scale processes that drive habitat change, and in part because they fail to recognize intrinsic habitat potential of individual restoration sites. The main goals of this research focus are to: improve understanding of how large-scale processes create diverse and dynamic habitats that support marine and anadromous species, better understand how human activities alter habitat-forming processes and habitats, develop new restoration techniques that are compatible with sustainable habitat-forming processes, and understand the variety of actions needed to adequately conserve intact critical habitats. In addition, NWFSC’s research will improve understanding of how new and existing habitat restoration and protection techniques affect fish and habitat at multiple scales (i.e., reach, watershed, Evolutionarily Significant Unit).
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.


PIT tag
Passive Integrated Transponder tags
the quantity or amount of something
using artificial streams to quantify the effects of salmon carcasses on food web processes
fish passage
effectiveness of fish passage facilities in restoring salmon populations above a barrier
quantifying effects of spawning salmon on resident food web using stable isotopes of C and N
juvenile salmonid
early life stages of salmonids
recolonization dynamics of salmon following reintroduction


Cedar River mark-recpature database
Access database
Changes in fish communities following recolonization of the Cedar River, WA, USA by Pacific salmon after 103 years of local extirpation.
Manuscript describing changes in fish populations as a result of salmon recolonization of the Cedar River.
Community and ecosystem attributes of the Cedar River and tributaries before arrival of anadromous salmonids.
Project report summarizing fish populations, fish diets and natural abundance levels of C and N isotopes in the aquatic food web of the Cedar River before salmon recolonization.
Cram. J., P. Kiffney, R. Klett, and R. Edmonds. (2011). Do fall additions of salmon carcasses increase abundance and biomass of periphyton, invertebrates, and fishes in experimental streams? Hydrobiologia 675: 197-209.
Manuscript describing the effects of a gradient of salmon carcass loadings on stream food webs in experimental channels.
Distribution and growth of juvenile coho salmon (Oncorhynchus kisutch) during colonization of newly accessible habitat.
Manuscript describing growth and distribution of juvenile coho in the Cedar River following salmon recolonization.
Habitat inventory and salmonid stock assessment in the Cedar River and tributaries.
Project report summarizing habitat and fish populations in the Cedar River watershed before salmon recolonization.
Heterogeneity on an experimental stream food web. Journal of Animal Ecology. Naman, S., P. Kiffney, G. Pess, and T. Buehrens. (in review) Temporal and spatial patterns of Cottus spp. in a small forest stream. Ecology of Freshwater Fish.
A manuscript in review describing the effects of coho recolonization of Rock Creek on resident sculpin.
Kiffney, P. M., C. Greene, J. Hall, and J. Davies. 2006. Gradients in habitat heterogeneity, productivity, and biodiversity at tributary junctions. Canadian Journal of Fisheries and Aquatic Sciences 63:2518-2530.
Manuscript describing gradients in physical habitat, productivity and fish populations in three Western Washington rivers around tributary junctions.
Kiffney, P., S. Naman, and R. Klett. (in review) Additive effects of resource subsidies and habitat heterogeneity on an experimental stream food web. Journal of Animal Ecology.
A manuscript in review that describes the effects of salmon analogs on an experimental stream food web.
Recolonization of the Cedar River above Landsburg by anadromous fish: ecological patterns and effects.
Project report summarizing fish populations for the first two years following salmon recolonization.


Class Insecta
Genus Oncorhynchus
Kingdom Plantae


George Pess
Principal Investigator
Peter Kiffney