DISCOVERY OF THE PHANTOM DINOFLAGELLATE IN CHESAPEAKE BAY

Since its discovery in natural estuarine habitat of North Carolina in 1991, the widespread impact of the toxic dinoflagellate, Pfiesteria Pi scicida (gen. et sp. nov.), popularly called the ''phantom'' dinoflage llate, on North Carolina fish stocks has been established, yet little is known about its influence outside of North Carolina estuaries. Here , we document the presence of P. piscicida in Chesapeake Bay. A fish k ill was observed after inoculating an aquarium containing mummichogs w ith sediment samples from Jenkins Creek, a brackish creek (salinity 11 parts per thousand) of the Chesapeake Bay system. I! piscicida was th e cause of the kill, as supported by morphological, physiological, and histological evidence. The appearance and behavior of the algae and s ymptoms associated with fish mortality were consistent with those prev iously observed in P. piscicida-associated aquaria fish kills in North Carolina. The discovery of P. piscicida in Chesapeake Bay supports th e speculation that these toxic dinoflagellates have a dramatic and far -reaching impact on fish stocks in shallow, eutrophic estuaries along the eastern United States.