FILMING SALMON AT THE SEATTLE SEAWALL

Using an Acoustic Camera to Observe How Fish Respond to Seawall Habitat Enhancements, Phase 2

In collaboration with the City of Seattle, investigators  utilize a habitat-friendly design for documenting activity around the downtown seawall, showing the way to better seawall design around the world.

Principal Investigator

Jeffery Cordell, University of Washington, School of Aquatic and Fishery Sciences

Co-Principal Investigators

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

Project

This project builds on previous WSG-funded research to incorporate juvenile salmon habitat considerations into the construction of the Seattle sea wall, and provide managers with effective options for improving juvenile salmon survival and survival of adults returning to spawn. Investigators are expanding upon current  Seattle Department of Transportation monitoring with additional funding that provides for snorkeling surveys and to install acoustic cameras mounted under survey kayaks, to image fishes in their environment. The approach will improve and enhance 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 will be coupled with snorkeling surveys along Seattle’s waterfront, conducted during the juvenile salmon spring out-migration period. The data will expand our understanding of how juvenile salmon are using these new habitat areas.

Research Updates

Background

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.

Results

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 will be the first city in the world to incorporate habitat panels into a large expanse of seawall. The city plans to monitor for several years after construction, generating the data needed to design future ecologically beneficial seawalls. More information is available at the .

Publications

Cordell J (2012) Habitat research. Interpretive panel installation, Waterfront Park, Seattle. Washington Sea Grant.

Annual Reports

2012 Final Report