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  • Elwha dam removal neashore monitoring and Salish Sea forage fish assessment


Northwest Fisheries Science Center (NWFSC) Fish Ecology FE - Estuarine and Ocean Ecology


Elwha Dam Removal - Nearshore
Elwha dam removal neashore monitoring and Salish Sea forage fish assessment
Removal (2011-2012) of two dams on the Elwha River, Washington is helping to restore natural sediment processes to the coastal environment near the river mouth. We are interested in the responses of fish associated with shallow subtidal and intertidal habitats subject to change as a result of these nearshore sediment processes. Nearshore habitats function as essential fish habitat for spawning and rearing of many fish species including ecologically important forage fish and federally protected species of Pacific salmon. Since 2006, we have been collecting species composition and size distribution of the subtidal/intertidal fish community in the eastern and central Strait of Juan de Fuca. Sites near the mouth of the Elwha River (with expected sediment deposition) and reference sites were sampled annually on a monthly basis from April to September using a beach seine. We have encountered over 45 species of fish, mostly juvenile stages, using sampled habitats in the Strait of Juan de Fuca. Some species tended to be very abundant, with catch dominated by three species of forage fish (Pacific herring, Surf smelt, and Pacific sand lance) followed by salmonids (primarily Chinook and coho salmon). Although the same mix of species tended to be present each year, they often exhibited dramatic variability in abundance between years. This suggests the importance of using multiple years of data to evaluate the drivers of such changes, including those resulting from dam removal. Sediment-impacted and reference areas exhibited some significant differences in abundance and diversity of several forage fish species and we found seasonality in the fish assemblage structure. Our results suggest some promising bio-indicators of short and long-term change in both the sediment-influenced and some reference areas in: 1) numbers of species, 2) species diversity, 3) composition and sizes of benthic species, 4) abundance by life history stage of surf smelt and Pacific herring, and 5) presence of migratory species like juvenile salmon. We propose to continue monitoring following dam removal and track these changes (including those directly attributed to dam removal). This is part of an inter-agency agreement (MOA) with the Lower Elwha Klallam Tribe and in collaboration with large ongoing forage fish projects at the University of Washington and Washington Department of Fish and Wildlife.

Data Sets

Research Themes

Ecosystem approach to improve management of marine resources
The California Current Large Marine Ecosystem, Puget Sound and the Columbia River Basin are home to a wide range of freshwater and marine resources that provide a wealth of ecosystem goods and services. Ensuring the resiliency and productivity of the California Current and Pacific Northwest ecosystems requires an integrated understanding of their structure, function, and vulnerability to increased human population growth in coastal communities and competing uses of coastal waterways and oceans. The NWFSC‘s approach to understanding these large ecosystems integrates studies across ecosystems (terrestrial, freshwater, and marine) and scientific disciplines to inform resource managers responsible for conserving marine resources.
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.

Research Foci

Characterize the interaction between marine, freshwater, and terrestrial ecosystem components
Although many species migrate between connected aquatic, marine, estuarine and freshwater environments they are commonly studied and managed as separate ecosystems. Environmental conditions in both marine and freshwater areas are strongly influenced by flows of water, sediment, organic matter and nutrients among ecosystems. Moreover, many threats (e.g., pollution, habitat loss, climate change, etc.) to marine organisms cross land-sea boundaries. Successful management of aquatic systems thus requires an understanding of linkages among ecosystems, including study of how specific habitats (e.g., headwaters, floodplains, submerged aquatic vegetation, nearshore zones, plumes and frontal regions) contribute to the productivity and capacity of ecosystems, and how to prioritize ecosystem protection or restoration within the context of the entire freshwater-estuarinemarine ecosystem.
Characterize the interaction of human use and habitat distribution, quantity and quality
The ability to define the state of an ecosystem requires insight into the natural processes within habitats, and how anthropogenic interactions with these processes can alter ecosystems and marine organisms. A wide diversity of human activities -- land use and water withdrawals, industrialization and dredging, fishing practices and climate change (e.g., ocean acidification) -- directly and indirectly impact critical freshwater, estuarine, and marine habitats. To best manage west coast marine, estuarine and freshwater habitats in a sustainable fashion, it is necessary to map the spatial and temporal footprint of human impacts and review their potential biological impact on each species of interest. Measurement parameters will be developed to determine the full range of human impacts using spatial data and improved habitat classification.
Describe the interaction between human activities, particularly harvest of marine resources, and ecosystem function
Humans are an integral component of ecosystems. These ecosystems provide goods and services such as fish and seafood harvests, but these activities and others such as habitat alteration, pollution, and ocean acidification, can have strong impacts. Understanding the nature of these interactions will require observational and experimental studies aimed at identifying ecosystem-level responses to human activities, both individually and cumulatively, as well as human responses to ecosystem changes. Modeling spatial choices for harvesting and other human activities that are affected by ecosystem integrity, for example, can support a better understanding of the effects of ecosystembased management actions.
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).
Understand how climate influences ecosystem variability
Effective ecosystem management will require an understanding of how climate variability and climate change will alter riverine, estuarine, and marine habitats and consequently how this will affect ecosystem status, function and recovery. Key research elements include better understanding of historical ecological variability through traditional (i.e., indigenous) sources, exploring the vulnerability of key species and biotic communities to expected habitat changes, including decreasing stream flow, increased flood frequency, increasing stream temperature, sea level rise, ocean acidification, shifts in ocean currents, and changed frequency and extent of deoxygenated zones. A secondary goal is to improve understanding of how ecosystems respond to year-to-year and decadal climate variability. Achieving these research goals will provide NOAA and state and local governments with the knowledge and tools needed to incorporate climate change and variability into management of living marine resources.


Chinook salmon
species of interest
Elwha River
river located on the Olympic Peninsula of Washington State
Oncorhynchus spp.
salmon species
Pacific herring
dam removal
related to removal of dams from rivers
fish community composition
species of interest


None associated


Species Clupea pallasii
Pacific herring
Species Oncorhynchus kisutch
Coho salmon, silver salmon
Species Oncorhynchus tshawytscha
Chinook salmon, king salmon, spring salmon


Anna Kagley
Principal Investigator
Kinsey Frick