This project will use new data and hydrodynamic modeling to determine the feasibility of using a breach in the bed of Bayshore Road to increase tidal circulation in Fisherman Bay (Lopez Island, WA), identify the most cost-effective solutions for the size and alignment of a breach, and evaluate potential impacts of the alternatives on existing aquatic vegetation, wildlife, and shoreline erosion in this 354-acre semi-enclosed estuary. Greater circulation will reduce summer water temperatures, hypoxia, and silt accumulation, improving habitat quality for rebuilding eelgrass meadows, which have declined steeply, and for Pacific herring spawning and early rearing (as preferred prey of migrating Chinook and Coho). San Juan Channel adjacent to the bay continues to be fished commercially and recreationally for Chinook (Blackmouth and summer), Coho and Pink salmon, although at levels far below historical levels of the 1940s-1960s. Climate change driven storm tides are rapidly degrading Bayshore Road, making a re-build inevitable within 10-15 years, and this project will provide herring-and-salmon friendlier alternatives to simply building a higher and wider road bed along the shore.