The types of poisoning syndromes caused by harmful algae documented in Australia can be divided into those that only impact humans or the marine food chain through the ingestion of seafood (Amnesic Shellfish Poisoning, Diarrhetic Shellfish Poisoning, Neurotoxic Shellfish Poisoning and Paralytic Shellfish Poisoning). In addition, other types of toxins have been reported to be produced from microalgal species in Australia, including maitotoxin, palytoxin, yessotoxin, and other groups. To date, these generally have not caused a problem with seafood consumption in Australia.
Harmful effects of algae can include death of marine life, human skin irritations or breathing difficulties. Marine life that has accumulated levels of toxins does not look or smell differently to other seafood, and therefore, without careful monitoring programs employing microscopy based phytoplankton identification and chemical analyses, it is not possible to detect whether seafood poisoning could occur.