Spatio-temporal distribution of Procentrum lima in coastal waters of the Gulf of Maine: A two-year survey

The dinoflagellate Prorocentrum lima (Ehrenberg) Dodge was found at several sites along the coast of Maine in 1998 and 1999, some in areas where shell fish are harvested commercially. Identity was confirmed by scanning electro n microscopy (SEM). Although this dinoflagellate is known to produce toxins (okadaic acid and derivative compounds), incidence of diarrhetic shellfish poisoning in coastal Maine is not well understood, despite confirmed toxic ity events in the early 1990s in Nova Scotia, Canada in adjoining waters to the north. Some samples containing the dinoflagellate came from wild musse l populations collected at low tide, while others originated from aquacultu re sites. Many of the cells were isolated from water samples and net rows a nd on a few occasions were associated with filamentous macroalgae. Prorocen trum lima appears to be relatively rare in Maine coastal waters, but its wi despread distribution over several months warrants increased monitoring to allay public health concerns.