Assessment of Spatial and Temporal Distribution of Crassostrea virginica Spat and Fouling Organisms to Determine Oyster Restoration Feasibility in the Maryland Coastal Bays

Biofouling, or the undesirable settlement and growth of organisms on submerged substrata, can be detrimental and have serious economic impacts. Fouling organisms also impede new settlement, such as the settlement of the Eastern oyster (Crassostrea virginica) larvae or spat, by competing for space and food. There is an interest in increasing the Eastern oyster population in the Maryland Coastal Bays (MCBs) through an oyster restoration project, however, in order to determine its feasibility, there is a need to study the spatial and temporal distribution of Eastern oyster spat and fouling organisms in this area. In our in-situ study, spat and fouling organism settlement was monitored biweekly from June through August 2019 at 12 sites throughout the MCBs using horizontal PVC settlement plates. We assessed the spatial and temporal variation in abundance (density) of the spat and the most prevalent fouling organisms, in addition to water quality parameters (temperature, salinity, dissolved oxygen, turbidity, and pH). Preliminary results suggest that spat density is highest in high flow areas that are closest to the inlets (Ocean City and Chincoteague Inlets) and that peak settlement occurred during the period from late June through July 2019. This project provides important insight into the spatial and temporal distribution of spat and fouling organisms in the MCBs. The information collected can serve as baseline data that can be used in future studies to help determine the likelihood of success of oyster restoration projects that could lead to a sustained Eastern oyster population in the MCBs.