An acidic cyanotoxin found associated with certain diatom blooms. Domoic acid can bioaccumulate in marine organisms that feed on the phytoplankton, such as shellfish and some fishes. In mammals, including humans, domoic acid is a neurotoxin responsible for Amnesic Shellfish Poisoning (ASP) , causing short term memory loss, brain damage, and in severe cases, death.