Are Juvenile Salmon LOVING the New Habitat at Vigor?

Preliminary Findings from Post-Restoration Monitoring

With the habitat restoration project at Vigor Shipyards completed in the Spring of 2023, University of Washington’s Wetland Ecosystem Team and Long Live the Kings conducted their first year of post-restoration monitoring this past spring. Monitoring efforts measure fish presence and density, insect abundance, and fish feeding habits within the newly restored area. The team also monitors nearby Jack Block Park, which represents a more natural shoreline not being restored to use as a reference and comparison for our measurements. Similar monitoring efforts were conducted in 2021, before the new habitat was constructed, so the team would have a baseline to compare to.

The goal of restoring habitat is to provide higher quality food for juvenile salmon as they migrate to the ocean, enabling them to grow larger and have a better chance of survival. If the results show that salmon are using the habitat for resting and feeding, it will be a good indication that more “salmon rest stops” could help salmon in the Duwamish estuary.

We know from studies of other habitat restoration efforts, that it can take time to show the benefits of the restoration. With one year of post-restoration monitoring data, we can say that we captured more fish in our sampling efforts this year than we did in 2021 when comparing fish densities within our nets, especially at Vigor. Before the restoration, the habitat at the Vigor site was very different and UW had to sample with a different type of net, however we can compare densities to get an idea of how the abundance of fish has changed.

Young pink salmon migrate out of the Duwamish River every even year. It was not a pink salmon outmigration year in 2021, so we captured no pinks, but this year was, and we caught the fish to prove it! In 2021 we didn’t capture any Coho or any steelhead—this year we caught both at Vigor. With only one year of data, it’s hard to say what this indicates since our reference site showed similar changes, but it is exciting to see juvenile salmon using the new habitat at Vigor.

Before restoration, no Chinook salmon were captured in the netting efforts at Vigor, but they were at Jack Block Park. This year, we captured Chinook at Vigor as well as at Jack Block Park! This preliminary finding is exciting, indicating that juvenile salmon are potentially using this area as a “rest stop” as they migrate.

We also collected insects in our traps set up in the newly restored vegetation at Vigor, which will allow us to compare to pre-restoration conditions. Juvenile salmon’s diets include insects and insect larva so if there’s plentiful food nearby, salmon are more likely to want to use the area to feed and grow. While the staff at UW are still hard at work analyzing the diet contents of the salmon we captured this year at Vigor, it’s a good sign there is more food around for salmon now than before the Vigor habitat restoration.

Results for an effective habitat restoration would show increased numbers of juvenile salmon at the site, more insects and benthic invertebrates (small animals living in the bottom sediment of the water—like aquatic insects and worms) in their diets, and an increase in insects sampled in the restored vegetation. We are looking forward to next spring, where we will gather more data to continue to tell the story of creating salmon habitat within an active industrial landscape.