Variability of Amnesic Shellfish Toxin and Pseudo-nitzschia occurrence in bivalve molluscs and water samples-Analysis of ten years of the official control monitoring programme.

•Evaluation of shellfish domoic acid occurrence from ten-year monitoring programme from Great Britain.•Frequency of toxin events increasing during this period.•Majority of toxic events associated with Pseudo-nitzschia blooms.•Shellfish toxicity not directly correlated with cell abundance.