shellfish poisoning shellfish poisoning shellfish poisoning includes four syndromes that share some common features and are primarily associated with bivalve molluscs (such as mussels, clams, oysters and scallops.) as filter feeders, these shellfish may accumulate toxins produced by microscopic algae, such as cyanobacteria, diatoms and dinoflagellates. shellfish poisoningspecialtytoxicology syndromes the syndromes are: amnesic shellfish poisoning (asp) diarrheal shellfish poisoning (dsp) neurotoxic shellfish poisoning (nsp) paralytic shellfish poisoning (psp)