When Drakes Estero, which lies within the Point Reyes National Seashore (PRNS) about 25 miles northwest of San Francisco, California, was designated by Congress in 1976 as Potential Wilderness, it contained a commercial shellfish mariculture operation. Oyster mariculture began in Drakes Estero with the introduction of the nonnative Pacific oyster in 1932, and has been conducted continuously from that date forward. Hence, the cultural history of oyster farming predates the designation of Point Reyes as a National Seashore in 1962. Nevertheless, with the approach of the 2012 expiration date of the current National Park Service (NPS) Reservation of Use and Occupancy (RUO) and Special Use Permit (SUP) that allows Drakes Bay Oyster Company (DBOC) to operate within the estero, NPS has expressed concern over the scope and intensity of impacts of the shellfish culture operations on the estero’s ecosystem. Public debate over whether scientific information justifies closing the oyster farm led to the request for this study to help clarify the scientific issues raised with regard to the shellfish mariculture activities in Drakes Estero.