Abstract In December 2003 a bloom of the toxic dinoflagellate Dinophysis acuminata (Claparede and Lachmann, 1859) was detected during routine plankton monitoring at Smoky Bay, on the west coast of South Australia (SA). Samples of scallops, razorfish and oysters were collected and analysed by LC–MS/MS to compare diarrhetic shellfish poisoning (DSP) toxin concentrations within the different species of shellfish that were exposed to the same bloom event at the same location. Toxin concentrations were compared in shellfish samples, which were prepared in ways reflecting how the organisms may be consumed. Toxin concentrations varied between species and only the oyster sample was found to be above the Australian regulatory limit of 0.2 mg/kg (okadaic acid equivalent). Toxin concentrations in both king scallops and razorfish were lower in samples where the viscera had been removed than in whole organism samples. The results reported here, although based on limited sampling, demonstrate for the first time the existence of a risk to public health from DSP in cultivated and natural shellfish in SA.