Publication Abstract

The current biotoxin monitoring programme in England and Wales is biased to cover commercially active classified shellfish harvesting areas and is split into two parts: the collection and examination of water samples for toxic plankton, and direct testing of shellfish flesh for biotoxins by mouse bioassay and High Performance Liquid Chromatography. These 2 programmes are undertaken at independent sites, with the exception of a small number of sites with recent histories of toxic algae problems which are monitored under both programmes. If the number of potential toxic algae in water samples exeeds the action level (Paralytic Shellfish Poisoning (PSP) = prsence Alexandrium spp. cells; Amnesic Shellfish Poisoning (ASP) = 150,000 Pseudo-nitzschia spp. cells/L); Diarrhetic Shellfish Poisoning (DSP) = Dinophysis spp./Prorocentrum lima cells/L; then shellfish samples are collected from the area for inclusion in the shellfish flesh biotoxin monitoring programme. A shellfish closure will not be sought until two consecutive weekly samples have exceeded the biotoxin action level (PSP = 80 µg STX equiv/100 g flesh; DSP = presence by mouse bioassay; ASP = 20 µg Domoic acid/g). A shellfish closure is usually obtained voluntarily through co-operation of commercial shellfish collectors in the area. A ban is not lifted until two consecutive weekly samples fall below the action level.