Algal Blooms and Marine Biotoxins: 1999 Publications

Author: Morton, S.L., Leighfield, T.A., Haynes, B.L., Petitpain, D.L., Busman, M.A., Moeller, P.D.R., Bean, L., Mcgowan, J., Hurst, J.W., and Van Dolah, F.M.
Title: Evidence of diarrhetic shellfish poisoning along the coast of Maine.
Publication: Journal of Shellfish Research 18(2): 681-686, 1999.
© National Shellfisheries Association

Notes: Following the occurrence of several unexplained incidents of shellfish-related gastroenteritis, field studies were conducted to determine if diarrhetic shellfish poisoning (DSP) toxins are present in Maine coastal waters. A protein phosphatase inhibition assay for DSP toxins revealed the presence of low levels of okadaic acid-like activity in blue mussels (Mytilus edulis) at sampling sites in the Frenchman Bay-Eastern Bay region. All other sites along the Maine coast were negative. Phytoplankton populations from this area were dominated by Dinophysis norvegica, a known toxic species. Two additional known toxic species of Dinophysis were also found: Dinophysis acuminata and D. rotunda. However, all plankton samples were negative for okadaic acid-like activity. Examination of the epiphytic communities from areas where mussels showed okadaic acid-like activity revealed the presence of the toxic dinoflagellate Prorocentrum lima in association with the brown alga, Ectocarpus sp. Epiphytic samples rich in P. lima were active in the phosphatase inhibition assay; subsequent analysis of these samples using LC-MS/MS identified the presence of dinophysis toxin-l (DTX-1). Empty P. lima thecae identified in the digestive tract of mussels from these areas indicate that P. lima is consumed by mussels. This is the first confirmation of P. lima in northern United States coastal waters and identifies DSP as a potential public health issue.