Average abundances of total Vibrionaceae in oysters (A and C) and seawater (B and D) determined using the COPP assay. Abbreviations: DE, Delaware; MD, Maryland; LE, Lewes; BO, Bowers; SB, Slaughter Beach; BC, Broad Creek; CR, Chester River; MR, Manokin River; OX, Oxford; TS, Tangier Sound.