New perspectives on biotoxin detection in Rangaunu Harbour, New Zealand arising from the discovery of pinnatoxins

Recent studies showing the presence of pinnatoxins in a range of shellfish from New Zealand and Australia (Selwood et al., 2010) prompted an investigation into historical mouse bioassay positives from Rangaunu Harbour, Northland, New Zealand. Eleven shellfish samples collected from the harbour between 1993 and 2008 were found to contain pinnatoxins as shown by liquid chromatography–mass spectrometric (LC–MS) analysis. Reanalysis of data from a quantitative mouse bioassay using an acetone extraction gave excellent correlation to pinnatoxin levels for seven of the nine samples tested. The cause of positive mouse bioassay results when using diethyl ether was not confirmed. A telephone survey of 22 Rangaunu Harbour residents confirmed that they had regularly consumed shellfish and other seafood collected from the harbour. Consumption was on average 2.6 times/week over 29 years. There were no reports of any associated illnesses.

► Pinnatoxins were found in all samples from Rangaunu Harbour.
► Pinnatoxin levels correlated to mouse bioassay toxicity.
► Rangaunu Harbour Toxin (RHT) is most likely due to pinnatoxins.
► Brevetoxins indicated by mouse bioassay were not be confirmed by LC–MS.
► No human illnesses were associated with pinnatoxins in our study or in literature.