Document Type



Virginia Institute of Marine Science

Publication Date



Marine Resource Report 00-2


As a consequence of the relatively warm temperatures and high salinities severe epizootics of both H. nelsoni and P. marinus occurred in most tributaries in VA. In the upper James River, VA prevalences and intensities of P. marinus were the highest on record. The proportion of advanced infections (moderate and heavy intensity) in October was 60% at Wreck Shoal and 48% at Horsehead Rock suggesting that significant oyster mortalities occurred in these areas. 1 Record high levels of P. marinus were also observed in Virginia's other major tributaries. Of the 39 bay oyster populations surveyed in the fall, P. marinus was present at all bμt one (Bell Rock in the York River) and most sites had prevalences exceeding 90%. Advanced infections bf the parasite were numerous, particulctrly in the Rappahannock River, and oyster mortality was high.



American Oyster Diseaeses, Virginia, Chesapeake Bay