The effect of harvest rates on eelgrass (Zostera marina L.) donor sites in Puget Sound: A project overview

Although not easily quantified, it is believed that eelgrass (Zostera marina), the predominant seagrass in Puget Sound, area has been lost because of increased shoreline development, periodic physical disturbances, and degradation in water quality. In response to that loss, the Puget Sound Partnership’s (PSP) Action Agenda specifically targets the restoration of 20% more eelgrass by 2020. This target equates to approximately 10,000 acres of eelgrass, which is about 2,500 acres larger than the largest existing meadow, Padilla Bay, on the west coast of the contiguous U.S. Restoring eelgrass will benefit a multitude of species valued in Puget Sound such as Pacific herring, Pacific cod, and Walleye pollock, as well as Federally and State-listed threatened and endangered species such as Chinook and Chum salmon, trout (steelhead), and Southern Resident Killer Whales (SRKW). Harvesting the amount of needed shoots (100,000s of shoots over time) to conduct restoration/transplanting could impact existing eelgrass meadows. The objective of this project was to conduct an assessment of how donor sites recover from varying degrees of harvest rates for eelgrass restoration projects in Puget Sound. The study assessed the effects of 0, 10, 20, 30, and 50% harvest rates in two donors sites: Anderson Island and north of Port Gamble Bay. This poster will describe the current project, discuss observed results from previous studies carried out in other locations in the US and show expected results and management implications from the current project.