Domoic acid was identified as the toxin responsible for a large outbreak of Amnesic Shellfish Poisoning(ASP) in Canada. Mussels were implicated in the outbreak; these had been harvested from the waters around Prince Edward Island. The most prominent symptom of ASP was memory impairment. Domoic acid is produced by certain marine organisms, such as red alga. Red tide monitoring systems have subsequently been successful in preventing human illness.