A recent publication in Estuaries and Coasts investigates the impacts of shoreline armoring along the Duwamish River estuary in Central Puget Sound on salmon diets, invertebrate communities and environmental conditions.
Approximately 1/3 of Puget Sound’s nearly 4,000 km of shoreline is armored: that is, the natural shoreline habitat has been replaced by bulkheads, sea walls, rip-rap, etc., designed to protect against erosion owing to wave action. Because of the importance of habitat interfaces for the function of many different types of ecosystems, researchers in Puget Sound are focused on how this habitat transformation is affecting the Puget Sound ecosystem, including intertidal species, food webs and water quality. Sarah Morley at NOAA’s Northwest Fisheries Science Center (NWFSC), along with colleagues from the NWFSC and the University of Washington, in a recent publication in Estuaries and Coasts have investigated the impacts of shoreline armoring along the Duwamish River estuary in Central Puget Sound on salmon diets, invertebrate communities and environmental conditions.
Greater species richness and density
Morley and colleagues found that at unarmored sites, epibenthic invertebrate communities were twice as taxa-rich and 10 times as dense (number of individuals per unit area) than at armored sites. In addition, the community of invertebrates found on the water’s surface, the neuston, was also more taxa-rich at unarmored sites. The diets of chum salmon were different between armored and unarmored sites, while Chinook salmon diets were not. This work by local researchers reflects the types of questions being asked about how shoreline alterations affect Puget Sound food webs and ecosystem function, and provides important information to help managers evaluate the trade-offs associated with different actions.