The Swinomish Indian Tribal Community recently began a restoration project to establish, expand, and research Olympia oyster, Ostrea lurida, populations on reservation tidelands. For our pilot project, we evenly distributed seeded cultch in two pocket estuaries in Similk and northern Skagit Bays during the summer of 2012 and spring of 2013. Subsequently, we initiated a long-term monitoring program that included measuring reproductive benchmarks to determine population expansion potential. While brooding data have been collected at one other site in northern Puget Sound (i.e. Fidalgo Bay), it is likely that oysters in pocket estuaries will be exposed to different environmental conditions than the Fidalgo Bay oysters. Our goal was to quantify the timing and environmental conditions for peak brooding of oysters in pocket estuaries. Brooding status was recorded from May to early September 2015 and water temperature was continuously logged at each of the two restoration sites. Our data clearly indicate that northern Puget Sound oysters located in pocket estuaries can begin brooding before May when daily minimum water temperatures reach 11°C, 2°C below the published thermal threshold. Managers and scientists working with native oysters in pocket estuaries should target early to mid-April as the optimal time for restoration expansion efforts
