Bivalves are considered ecosystem engineers and are important for ecosystem health within estuaries. The Olympia oyster Ostrea lurida was historically important along the Pacific Coast of the United States but currently has low population abundances along much of its historical distribution. However, despite restoration efforts, little recovery has been observed. Here, we provide a short review of the biology of the species and recent efforts of restorations. We then examine potential contributing factors to limited recovery in the Coos Bay estuary. We noticed distinct variations in larval supply along the bay and proposed hydrodynamics of the bay could be causing these variations. We then collected observational data on the hydrodynamics of the bay and the distribution of other larval bivalves. These data support the presence of a null zone within the estuary that may be driving the distribution of larval bivalve taxa. This thesis includes unpublished co-authored material.