FILMING SALMON AT THE SEATTLE SEAWALL
In collaboration with the City of Seattle, investigators utilized a habitat-friendly design for documenting activity around the downtown seawall, showing the way to better seawall design around the world.
Jeffery Cordell, University of Washington, School of Aquatic and Fishery Sciences
John Arnseen, City of Seattle, Department of Transportation
Charles Simenstad, University of Washington, School of Aquatic and Fishery Sciences
Jason Toft, University of Washington, School of Aquatic and Fishery Sciences
This project built on previous WSG-funded research to incorporate juvenile salmon habitat considerations into the construction of the Seattle seawall and provide managers with effective options for improving juvenile salmon survival and survival of adults returning to spawn. Investigators expanded upon Seattle Department of Transportation monitoring with additional funding that provides for snorkeling surveys and to install acoustic cameras mounted under survey kayaks in order to image fishes in their environment. The approach improved and enhanced data gathered about juvenile salmon in nearshore urban environments by providing data to be collected in areas and times of otherwise poor visibility (such as at night). This was coupled with snorkeling surveys along Seattle’s waterfront, conducted during the juvenile salmon spring out-migration period. The data expanded our understanding of how juvenile salmon are using these new habitat areas.
Seawalls protect urban infrastructure but degrade habitat for fish and other wildlife by transforming complex shorelines into simplified vertical walls. The replacement of Seattle’s seawall presented an opportunity to improve habitat for wildlife, including several salmon species that migrate through the area.
Second-phase results corroborated the initial findings: the relief panels (with steps and fins) supported more diverse communities than the existing seawall or flat panels. Some populations, such as mussels, reached densities on the flat panels resembling those in more natural habitats. Although initial results indicated that juvenile salmon found more prey on the relief panels, no consistent pattern emerged. As a result of this collaboration, Seattle was the first city in the world to incorporate habitat panels into a large expanse of seawall. The city planned to monitor for several years after construction, generating the data needed to design future ecologically beneficial seawalls.
Cordell J (2012) Habitat research. Interpretive panel installation, Waterfront Park, Seattle. Washington Sea Grant.
