ONLY TIME WILL TELL: SUCCESSES AND FAILURES OF RESTORING NATIVE OYSTER POPULATIONS IN HABITAT LIMITED SYSTEMS

Historically, Olympia oysters (Ostrea lurida) played an important economic, ecological, and cultural role as Washington's only native oyster. Yet, due to overexploitation, loss of habitat, and other human-related factors, only ~5 % of the once-known beds remain in Puget Sound. In 2012, the Swinomish Indian Tribal Community began a small-scale Olympia oyster restoration effort with the intent of eventually establishing self-sustaining populations that could act as larval sources for additional sites. During the onset of the project, w e initiated a monitoring plan to track survival and growth of outplanted seed by site. Initially encouraging results lead to the expansion of our restoration project and  research objectives . Preceding work addressed the following goals: (1) determine when our population of oysters were brooding, (2) investigate local larval supply and distribution to better target habitat enhancement efforts, (3)  continue to monitor oyster growth and survival while examining surrounding habitat for signs of recruitment, and (4) quantify parameters of ecological change before and after restoration. These oyster populations successfully brood at low temperatures and late-stage larvae were documented in areas surrounding restoration sites .  Despite the presence of larvae,  we have not found definitive evidence of successful recruitment in the area. Specifically, we last seeded our sites in 2017, yet we did not record signs of new cohorts in 2018 or 2019 (Fig. 1). Quantifying ecological change due to restoration efforts is more difficult  when the population does not expand naturally.  Our combined results highlight the importance of consistent monitoring and analysis, as we were able to identify  the  lack of recruitment and respond by developing innovative approaches to enhance methods  for successful  future restoration.