The West Waterway of the Duwamish.

Project Title

Evaluating habitat restoration opportunities for Pacific Salmon within the Duwamish River, an urban estuary

Description

The Duwamish River Estuary, connecting the Green River to Elliott Bay in downtown Seattle, is home to eight species of anadromous salmonids that rear and migrate between fresh and saltwater habitats. Due to extensive industrial development along the Duwamish River, there is concern that lack of high-quality estuarine habitat is contributing to low salmonid survival rates within the greater Green River Watershed. Millions of dollars are being spent annually on restoration efforts along the Duwamish, yet relatively little is known about current habitat availability or fish use within this urban estuary.

The objective of this study is to evaluate the role riparian vegetation and bank armoring play in nearshore habitat quality for juvenile salmonids within the Duwamish Estuary. Within this framework, we are pursuing five related lines of questioning:

• What is the extent and spatial distribution of riparian vegetation and armoring of nearshore habitats within the estuary?
• What role does riparian vegetation play in regulating nearshore temperature regime and the availability of terrestrial insects in a tidally influenced environment?
• How does bank armoring influence benthic invertebrate and fish use of nearshore habitats?
• What is the distribution of non-indigenous invertebrates within the estuary and are such species present in higher proportion at more disturbed habitats?
• How does fish use of nearshore habitats within the estuary correspond to temperature regime and availability of invertebrate prey resources?

Mapping the Duwamish shoreline.

Investigators

Sarah Morley

Collaborators

Jason Toft (University of Washington), Karrie Hanson (NWFSC), and Julie Hall (Seattle Public Utilities)

Support

NOAA Fisheries

Project Status

Data collection and sample processing complete; data analysis and manuscript preparation in progress

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