Oyster reef habitats in Chesapeake Bay declined sharply in the last century, which stimulated substantial restoration efforts. To assess the effectiveness of reef restoration, reef performance has been monitored using a combination of habitat mapping and field sampling. Reef monitoring has been conducted effectively for deep and intertidal reefs, but shallow, subtidal reefs have not been mapped accurately due to logistical challenges. Here, we provide a protocol to sample shallow, subtidal restoration reefs accurately. Felgates Creek reef is a shallow (depth), subtidal oyster reef constructed in 1999 in the York River, VA; the reef has not been mapped, which has precluded accurate monitoring. The goals of this study were to: 1) map Felgates Creek reef and delineate sampling strata, 2) quantitatively assess reef performance by stratified random sampling, and 3) demonstrate mapping utility for other shallow, subtidal reefs such as Felgates Creek reef. A high-resolution, remotely operated Acoustic Doppler Current Profiler and RTK GPS base station was used to map the reef and define sampling strata by depth. Fourteen random samples were collected, nine from the shallow depth stratum, 0.5-1.0 m water depth, and five from the deeper stratum, 1.0-1.5 m depth. A 0.25-m2 quadrat was placed at each sampling point and all shell material within the plot was excavated. Oysters were sorted into live and dead and shell lengths were measured. The volume of each oyster was determined via volumetric displacement. Oyster density was high (58 live oysters per m2) in the shallow stratum and rapidly declined to three live oysters per m2 in the deep stratum. Multiple age classes were present in the shallow stratum, which, when combined with the high density, indicates that the shallow portion of the reef has persisted over the past two decades. The advanced technologies utilized in this study allow for the assessment of restoration oyster reefs in shallow water depths, which can be used to guide monitoring of reef performance in restoration efforts.
Dean-McKinney, Kate, "Monitoring performance of shallow, subtidal restoration oyster reefs using advanced technologies: A case study on Felgates Creek reef (York River, VA)" (2021). Geology Senior Theses. William & Mary. Paper 1.
Available for download on Friday, May 12, 2023