The objective of this study was to improve understanding of pathogen and pathogen indicator occurrence in shellfish growing waters by characterizing the bacterial community composition over time at a monitoring station in the Chesapeake Bay (Maryland, USA) and to identify members of the community that co-occur with indicator and Vibrio bacteria.16S rRNA diversity and estimated abundance were compared to culture and qPCR based quantification of select bacterial human pathogens. T. thermophilus genomes were added to each sample as an internal control and potential method of estimating 16S gene density.