Oyster population demographics are used to estimate shell standing stock (g m^–2) and rates of shell production (g m^–2y^–1) and loss by oyster, Crassostrea virginica, populations in both the Virginia and Maryland portions of the Chesapeake Bay. Source data are from long-term stock assessments whose footprints cover the majority of extant fished reefs in Virginia and a mix of fished and sanctuary reefs in Maryland. Individual longevity in extant fished populations is typically less than or equal to 5 y and truncated when compared with fossil C. virginica populations. Shell standing stock and productivity are maximal in year 1 or 2 of the progression of a year class through the population. Maintenance of the underlying reefs structure is dependent on regular shell input from mortality. The combination of truncated population structure and variable recruitment make shell addition temporally unstable. High turnover rates (≥30% y^–1) of the shell substrate pool in the oxic region above the sediment water interface are present. Reef accretion rates are generally less than the combination of sedimentation and relative sea level rise in most of the Bay system. Greater individual oyster longevity is required to ensure development of self-sustaining reef structures in the Chesapeake Bay.