Reestablishing larval connectivity in an estuarine landscape: the importance of shoreline and subtidal oysters (Crassostrea virginica) in a comprehensive oyster restoration program Restoration Ecology

The decline of oyster reefs in estuaries has resulted from a combination of chronic and acute disturbances. The loss has resulted in decreased yield for the oyster fishery as well as a decline in ecological benefits that has led to increased efforts to restore oyster reefs. The need for scientific guidance in accomplishing these restoration goals has become even more pressing in the northcentral Gulf of Mexico in the wake of injury to oyster reefs resulting from the Deepwater Horizon oil spill. Restoration of both the shallow, marsh‐fringing oyster aggregations and the deeper subtidal oyster reefs is necessary. Historically, fringing oysters have been overlooked in the oyster habitat landscape because of their limited commercial value. Here, we use a biophysical transport model to examine the transport and settlement of oyster larvae in known oyster reefs along the coast of the northcentral Gulf of Mexico. The modeling demonstrated that the majority of oyster larvae settle within the embayment (>98%) or sub‐basin (>65%) of their origin. Additionally, the model demonstrated the importance of fringing oysters as a source of larvae to re‐seed other fringing oysters along marsh edges as well as subtidal oyster reefs. We conclude that networks of reefs, including both fringing oyster habitat and subtidal oyster reefs within sub‐basins, are necessary to provide resilience to the population at the sub‐basin level. Finally, we conclude that fringing oyster habitat may serve as an archipelago‐like network to enhance larval supply and connectivity for oysters throughout the mesosaline portions of estuaries.