The Hood Canal Bridge carries traffic across the northern outlet of Hood Canal, connecting the Olympic and Kitsap peninsulas and supporting tourism and other economic activities. As a 1.5-mile long floating bridge, its pontoons span over 80% the width of Hood Canal and extend 15 feet underwater. Because of its location, all salmon and steelhead must navigate around or underneath the Hood Canal Bridge on their migration to and from the Pacific Ocean. This project was designed to pinpoint how the Hood Canal Bridge affects Endangered Species Act-listed juvenile steelhead survival, determine whether other salmon may also be affected, and determine whether - and if so, to what extent - the bridge impacts the health of the Hood Canal ecosystem. The project included two years of intensive data collection at the bridge and in surrounding waters, data analysis, synthesis, and modeling. LLTK coordinated with federal, state, and tribal partners and, through this project, characterized physical and biological dynamics near the bridge and identified bridge impacts to juvenile steelhead and salmon, predator assemblages, and water quality parameters. The results and recommendations of this project are already being used to drive management actions to mitigate bridge impacts on juvenile steelhead survival; LLTK and partners have completed initial scoping and design recommendations for short-term solutions to install at the bridge that will facilitate fish passage and discourage predation. LLTK also engaged in public and legislative outreach and communications throughout the duration of this project via factsheets, presentations, and the online Survive The Sound game (www.survivethesound.org) which used real data from juvenile steelhead tagged as part of this project. Brief results from this project: The Hood Canal Bridge significantly contributes to early marine mortality of juvenile Hood Canal steelhead by impeding fish passage and facilitating predation; The bridge impacts other fish species such as juvenile Chinook and chum; The bridge significantly impacts water quality parameters (temperature, salinity, currents) in its vicinity. Although bridge effects on water quality dissipate with increasing distance from the bridge and do not appear to propagate throughout Hood Canal, these near-bridge changes in circulation and flow may be linked to impacts on juvenile salmon and steelhead behavior and mortality; Avian and mammalian predators were documented near the bridge. Harbor seal predation on juvenile steelhead was the most frequent source of mortality based on tagged juvenile steelhead mortality patterns; The Hood Canal Bridge Impact Assessment Phase 1 Report (included as an attachment in this final report) includes detailed results from each of the six research activities listed above, as well as synthesis across research activities. As of March 2020, all the federal PCSRF funds were spent and all field work and data synthesis was completed. Remaining PSAR funds were used to complete final reporting and recommendations for upcoming phase 2. As of 10/15/2020 all work is completed.